TULLvTIN NO. 132. ALABAMA APRIL, 1945. Agricultural Experiment Station OF THE Alabama Polytechnic Institute, AUBU RN. Diseases of the Apple, Cherry, Peach, Pear aMdP1um;. With Methods of Treatment. By -E. MEAD -Plnt WCILCOX, PH. D. (Harvard) Ehysiologist and Pathologist. C:pelikia, The Ala,: Post Publishing Company. 1911 . COMMITTEE OF TRUSTEES ON EXPERIMENT STATION4. J. T. W. M. CARMICHAEL....................................... Montgomery.,. .Opelika,. ,............. D. SAMFORD.............................................. C. DAVIS ................................. Jasper;, STATION COUNCIL. C. C. THACH ....................................... ......... Presi'dent.. 3. F. DLJGGAR.................... ....... Director and Agriculturist.. B. B. Ross.. .. ,,. ............ C. A. CARY.............................. ......... Chemist and State Chemist. ............... Veterinarian.. E. M. WILCOX............... ... Plant Physiologist and Pathologist.. R. S. MACKINTOSH.......... Horticulturist and State Horticulturist,. J. T. ANDERSON.............. Chemist, Soil and Crop Investigations.. ASSISTANTS. C. L, HARE............. ..................... T. BRAGG ................................ .1. H. MITCHELL..........................Third First Assistant Chemist.. Second Assistant Chemist. Assistant Chemist. N. C. REW ... ......... .... Assistant in' Animal Industry.. C. M. FLOYD....................... ........ .......... ,........... .Superintendent of Farm.. I. S. MC ADoRv ........ C. F. KINMAN................... Assistant in Veterinary Science.. Assistant in Horticulture. The Bulletins of this Station will be sent free to any citizen the State on application to the Agricultural E perimnt Station,, of Auburn, Alabama. TABLE OF CONTENTS. INTRODUCTION.............................. APPLE Diseases........................................a Bitter Rot........................................ ......... Par& 7i x 4 Black Blight ........................................... Canker .......................................... Fly Spek ....................................... Hairy Root.................................. Rust ... Scab Knot...................................... 89.. 12'3 91. 3 .94L, 95~. 97. 84~. ....... ..................................... ............................................... .. .................... Sooty Blotch........ .............................. CHERRY Diseases................. BlaK-: 102-. -not ........................................ ......................................... Brown Rot ........................................ 10 3. 1oi3. 109-. 100.. 100.. Guninosis......................................... Leaf Spot PEACH Diseases......................................... Brown Rot........................................ Crown Gall .......... ................... Gumniosis ........................................ Hairy Root............. ................... Leaf Curl ........................................ r..a 109n. 100. 113. 100:. 94.. 1 Rosette.............. ......................... Yellows........................................... PEAR Diseases..........................................a 119. 121. 12". 12_. 127. 129'. 131.0. . ...... .o... Blight..................... ....................... Leaf Blight ....................................... Scab .............................................. PLUM Diseases .................. ......... Black Knot ....................................... Brown Rot ................. ............ 103 .............. Canker.................................... Gumnrnsis ...- . 109 1 1. .......................................... .. w. . .... 10'.n. Leaf Spot............................. Plum Pockets......:............................... FUNGICIDES........................... _.. ... o-- 1004_. 13k2. .Ie3.. Ammoniacal Copper Carbonat ................... Bordeaux Mixture........................ Lime-Sulfur-Salt Wash............................ EXPLANATION ........ o1L Plates..,.................. 134,. 1.3g.. .............. 10 INTRODUCTION. The rapid increase in the fruit growing industry in this State within recent years has made it necessary that more and more attention should be given to the diseases of these plants by the Experiment Staation and the fruit-growers themselves. A large number of letters reach this department during the year asking for information regarding these diseases and the best method of controlling them and these letters cannot in most cases be properly replied to by letter alone. They indicate also a growing interest in these matters and seem to indicate that the time has arrived to place before our people such information as is now available regarding these matters. To supply this evident need this Bulletin has been prepared. We have thought it best to depart somewhat from the common method of presenting such matters and have made the attempt to arrange the facts and suggestions under such definite headings as will best serve to indicate what sort of information must be had before one can hope to successfully control diseases of cultivated plants. More than this we have looked upon the diseases from the standpoint of the diseased plant and have included, therefore, no statements regarding the organism causing the diseases where this would not conduce to a clearer understanding of the disease itself and particularly of the methods of treatment suggested. The science of plant pathology owes much to mycology but its future advance and recognition depends upon its rather more sharp differentiation from "economic mycology." The plants are arranged in alphabetical order by their common names and under each are given, also in alphabetical order, the most important diseases of these so Pilants in our region. W e have introduced uo flew common -names for any of these diseases, but have employed the cornnames, nOw in most common use or that are sanctiond Jy the calin ug authorities upou this subject. In cases where disease is known on more than of the plants -ieationed reference to the disease will be made uuder each, niut its full description will be presented under the first mentioned or in connection with the plant in which mliL= ,thee ,iU:ease is liere best known, If the disease shows specific li eivuces in tie different plants attacked mention of the it-t will he r i-cl(de( unler s plant concerned. Meth v-ls of treatiien are discussed under each disease and no '_spray calendar" is given. It is believed the plan here adapted has several and peculiar advantages over the other jnethiod. Te have placed at the close of the discussion of each disease a bibliography of the disease. This bibliography is in no case complete, but is simply a select list of the more srwiginal and recent literature dealing with this subject. The majority of these references are to the literature of the Iate Experiment Stations and the Department of AgriculTo these and other sources I am indebted for infor nation here presented the references to this literature rre here included to show readers of this Bulletin that efuther reading and study of this matter of plant diseases -,noii -vhfie same one each , .re. and in may .. readily be made may the publications mentioned that in. cases be had for the asking. most One of- the' principal purposes of thiis Bulletin is to enable tfrait growers to 'recognize some of the common diseases of the plants mentioned in order that they may assist this :cand severity -; tate. diepartmuent in securing data each year of the distribution of the diseases in the various counties of the The method employed here in recording this infor-nlation well shown by the figures on pages 82 and 83. The first one shows the front and the last one the back of a rjecord .form so made as to be employed in a regular loose 'is 81 tleaf holder. We wish specimens and information regarding ,each disease from every county of the State where it is to ,be found and shall be glad to afford any who care to assist 'us in gathering this information any special directions they may desire. Specimens of diseased conditions of any plant are at all times desired and these and letters regardsing such subjects should be directed to the Department of 'Plant Physiology and Pathology of the Experiment Station. DISEASE YEAR NOT9Sd O OO REPORTED BY COUNTY POSTOFFICE DATE FILE and COPY APPLE. BITTER ROT. HISTORY AND DISTRIBUTION The bitter rot of apples, known also as the ripe rot or aunthracnose of the fruit, certainly made its appearance in America previous to 1867 and has attracted much attention from that time to date. In the United States the disease is found in practically every State east of and including Kansas, Oklahoma and Texas; the most serious outbreaks of the disease have occurred in Oklahoma, Indian Territory; southern Illinois, Ohio and Indiana; Kentucky, West Virginia, Virginia, eastern North Carolina, western New York; Delaware, Vermont, New Hampshire, Massachusetts, Connecticut, Rhode Island, New Jersey and Alabama. The fungus causing this disease may be fairly said to be found the world over wherever the apple is grown and, in addition to the apple, has been found on the following hosts: pear, tomato, grape, peach, nectarine, apricot, pepper, egg plant and squash. It remains to be determined whether the fungus occurring on these various hosts is identical. SYMPTOMs. The bitter rot or ripe rot of apples is a fungus disease of the ripening fruit producing in another form a canker of the smaller limbs of the apple tree. The'first sign of the disease is to be found in the form of a small discoloration just beneath the skin of the apple. This spot, as it enlarges, becomes more and more sunken and the rotting of the apple proceeds towards the core. When the spots reach a size of about a half inch in diameter small blackish bodies appear in a circular arrangement beneath ,the skin of the apple (Plate I, Fig. 1.). These blackish :bodies are :the fruiting bodies of the fungus and soon pro._ject ifrom the surface of the diseased spot. As these fruiting bodies break through the surface of the apple the spores produced in them are allowed to escape. The spores are held together in the form of stringy pinkish masses which are quite conspicuous, particularly on dry quiet nights when the spore masses are oozing out. As the disease progresses other rings of fruiting bodies will appear outside of the one first formed and in time there may be a half dozen or more of these concentric rings. If the climatic conditions are unfavorable to the rapid development of the fungus the rings of the fruiting bodies will not be so definite or may be absent entirely. From the .original point of infection the fungus may grow out until the whole apple is rotted-though there is at all times a rather sharp line of separation between the healthy and diseased portions of the fruit. If infection occurs at more than one point the rings of fruiting bodies from the several infections will ultimately unite with one another. The general effect of the fungus is to hasten the maturity of the apple and lead to the well known falling of the apples. This falling may occur at any stage in the development of the disease. In fact the premature falling of the fruit is one of the most conspicuous symptoms of this disease. During the summer of 1902 a Mr. Simpson, of Illinois, a large fruit grower of that State, noticed that in many cases was to be found a canker on the limb that he suspected of being the source of infection from the fact that thle canker was often found at the top of an inverted cone 'formed by the diseased apples on the tree. A careful investigation of this matter by Blair and Burrill and by Von Schrenk and Spaulding has established this suspicion of Mr. Simpson as a fact. They were able to produce the typical bitter rot by inoculation of healthy apples with spores produced in these limb cankers and also to produce the limb ,canker through inoculation with spores obtained from dis- __here eased apples. This very important discovery introducedE into the treatment of the disease a new factor of immenseimportance. These cankers appear most generally on the smaller limbs, and their general, appearance is well shown in Fig. 2 on Plate II. are other cankers of apple trees and of other trees due to various causes, but whenever the bitter rot of apples is found on trees on which cankers like those shown in the above figure occur the removal of the cankers would be advisable even in advance of a demonstration of the connection between the two troubles. 'There RELATIONSHIP OF DISEASE TO CLIMATIC CONDITIONS. The first appearance of the trouble on the apple may be expected during July in this latitude, though in the northern apple growing districts this is generally delayed until August. The exact time depends much upon the climatic conditions that prevail at the time and during the spring. The green fruit is generally quite immune, a fact that may be due to the larger amount of malic acid in immature fruits as compared with ripe fruits. And it is this rapid destruction of the ripe fruit just when the owner is about ready to gather in the crop that makes the trouble so much dreaded ! Warm and sultry weather affords the best chance for the rapid development of the fungus and the appearance of a regular bitter rot epidemic. On the contrary in cool dry summers the trouble need not be much feared. Nights with much dew alternating with hot days will greatly promote the development of the fungus. The time of first appearance of the trouble on the fruits. may also be much influenced by the condition of the spores, as to ripeness, in the cankers and the mummies, to be described later. If a cold spring has delayed the formation of these spores then the rot will' be late, appearing on thefruit itself. 87 ECOTOMIC IMPORTANCE ,disease cannot do better to emphasize the importance of this than to iention the statement of the President of .ihe National Apple Shippers' Association who said, "the damage to .the apple crop of the United States in 1900 from hitter rot was $0,000,000.00."'The destrnction of 75 per cent. of the crop by this disease is not very nnsnal and in many cases the owners of apple orchards have preferred to lease the orchard for a mere trifle than to mn the risk Schrenk and Spanlding ~of getting no returns at all. say, in speaking of this disease, that "It has probably done -more to discourage apple growing in many regions than all other tronbles, inclnding both fnngns and insect diseases combined." In onr State the disease has cansed great losses in many places, but so far no very systematic attempt has been made to control the disease or to determine its exact d istribution. We Von AETIOLOGY. The bitter rot of apples and the associated canker of apple limbs are prodnced by the fnngus now known as Glomntrella 'iafo maculans (Berk.) Spaulding and Von Schrenk. REMEDIAL MEASURES. .our The treatment against this disease nmay, in the light of present knowledge, be grouped nnder three (1) removal and destrnction of all diseased app'sM from the tree and from the gronnd, (2). removal of the ca.nkered headings: limbs, and (3) spraying with the regnlar Bordeanx mixture during ,s- directed below. The spores formed on the apples that fall to ;the gronnd the season and those on the apples that dry up to, form mummies on the tree may live over the winter and thns constitnte sources of new infection dnring the following spring. If only ,a few trees are infected it will cer- tainly pay well to watch the spread of.the, disease and'inn mediately pick and destroy by burning or burying in the ground every apple as soon as the disease appears upon In this way the further spread of the disease to other trees the orchard will be largely prevented. And then rotten apples on the ground should be gathered up and stroyed. The limb cankers should be removed during the late fal or winter as they can then be seen ure readily than they can when the trees are in leaf. If cankers are found on the smaller limbs as is generally the case, these limbs may be removed entire, but if found on the trunk or very large limbs it may.be best to carefully cut out the cankered and paint over the wound carefully with white lead paint of tar. It seems certain now that the removal of all these cankers will do much to lessen the spread of the dis ease in the orchard by removiig one of the sources of new infection. In addition to the two above named precautions the should be carefully sprayed with Bordeaux mixture at least once before the buds open and then at intervals of ten days unti.l_ the fruit is about ripe. in it all tion por- trees BIBLIOGRAPHY,. Alwood, W B. 1894. Ripe rot, or bitter rot, of'apples;. Bull. Va. Exp;:_ Stat. 40 :57-82. p1. 1-2.. 1904.0 Orchard Studies-XV. The, bitter. rot of ap7 ples. Bull. Va. Exp. Stat. 142 :249 1-4._ 279. p1. Burrill, T. J., and Blair, J. C. 1902. Prevention of Bitter~ Rot.. Cire. Ill. .Exp. Stat.. 56:1-3.- 1902. Bitter Rot of Apples. 77:51 66.fig.. 1-12'.,pl.. C. Ill. Bull. Exp. Stal-73136 within contains the s'ateinerit *This Bulletin buars the date Nw)ember,, 1902, on its cover,. "Issued Febtunary 20, 1904." buts 89 Garman, H. 1890. The bitter rot fungus of apples. (Gloeosporiiuw cersicotor. B. & C.) Rept. Ky. Exp. Stat. 2-1889; 43-45. fig. 13-15. Haisted, B. D. 1892. Apple Bitter Rot or Ripe Rot. Bull. N. J. Exp.. Stat. 86:16i. Longyear, B. O. 1904. Bitter rot, ripe rot, anthracnose. (Glomerella ruforaculans (Berk.) Spaulding&Von fig 4 5., Special Bull. Mich. Exp. Stat.'25 Stinson, J. T. 1894. Bitter Rot, Bull. Ark. Exp. Schrenk.) :9-10. Stat. 26 :33-35. Preliminary report on bitter rot or ripe rot of apples. Bull. Mo. Fruit- Stat. 1 :21 pp. Von Schrenk, H., and Spaulding, P. 1903-The Bitter Rot of Apples. Bull. Bureau Plant 1901. Ind. U. S. Dept.' Agr. 44:54 pp. pl. 1-9. fig. 1-9.. BLACK ROT. This disease has been known for some time being reported' from Illinois for example as early as 1878. It probably oc curs in every apple orchard and is often confused with the bitter rot. SYMIPTo1MS. Brownish decayed spots appear on the apple generallynear the stem and often near the flower end.: This rotted area soon turns, black and the rotting proceeds towards, the center of the apple. There is no such sharp deinarkation between the rotten and healthy portions of the apple as exists in the case of the bitter rot and this is one method ;surface of distinguishing the two diseases from each other. the "decayed spot becomes someWhat, depressed'. of The,. 90 -Finally the apple shrivels up more or less and becomes a small and hard "mummy." This disease does not occur as a rule on green apples ex-cept in cases of injury to the apple by wounds or insects. It is often abundant on "windfalls." It is also one of the chief causes of rotting of apples in the market. On the leaves the same fungus often causes rather serious damage through the formation of rather large and irregular brownish spots. The old dead twigs on unpruned trees may often become breeding places for this fungus from which spores may be scattered by the wind. The fungus was once thought to live on the twigs merely as a saprophyte but is now known to cause a serious canker of apple twigs. (See Canker of Apple on page 91.) AETIOLOGY. It is produced by the fungus Sphaeropsis malorum, Berk. The fruiting stage consists of numerous rather small black pustules that develop on the surface of the diseased apple. The pustules develop as a rule only after the rotting is fairly well advanced. These pustules are roundish conceptacles, with black or purplish walls, containing the spores. The spores ooze out as small white threads. The spores are at first white, but soon become deeply colored. TREATMENT. The disease may be controlled by spraying with Bordeaux mixture, making the first application before the leaves appear and subsequent ones at intervals of about two weeks. (See Fig. 6 on Plate II.) Decayed fruit should be removed from the trees and the ground and destroyed and "mummy" fruits should not be allowed to remain on the tree over viniter. Since the fungus causing this disease. is also shown to 91 The 1902. tGarmuan, the cause of:a canker, care should be taken to remove or ltreat cankered limb as suggested under the bitter rot. BIBLIOGRAPHY. 'Clinton, G. P. Black Rot. Sphaeropsis malorum Berk. I11. Exp. Stat. 69 :192-193. fig. 2 on p1. Bull. B. H. Spraying Experiments in 1895. Bull. Exp. Stat. 59 :111 129. fig. 501-508. .Scribner, F. L. 1890. Black rot of the apple. Fungus diseases of the grape and other plants and their treatment. 81--83. fig. 1606. CANKER. HISTORY AND 1)IsmIBuTION. This disease was first reported from New York State, but is now knowfn to have a much wider distribution. The fact of its being caused by the fungus producing the well known 'black rot of the apple, pear and quince fruits would naturally lead one suspect that the distribution of the canwould coextensive with the black rot. SY1IiPTOMS. In general a canker may be said to be the result of any "injury that destroys the bark and lays bare portions of wood." (Bull. 170 Y.) This particular canker is due the action of aaitcfnu that attacks principally the 1.895. Ky. 'ker "be to N. to larger limbs. Tile'trouble may 'be detected- from the swollen appearance of. the limbs and the rough dark colored bark. (Plate VII. Fig. 19.) Frequently in severe cases of canker the wood itself may be exposed and thus decay of the wood itself begins.. The extent to which the canker af- but fects the varies apparently with various conditions,. muay be several feet. bark The effect upon the tree is due tothe-interference witl the circulation of the sap and the amout of injury willoQ course be in proportion to the surfacearea of the cankers. The tree may be simply weakened or may he killed outright.. AETIOLOGY. This canker is caused by the fungus-Spaveopsi&nalorlh. .Pk. TREATMENT. Cankered limbs should, if possible; be/removed'and burned. Where the cankers are found on the trunk or very large limbs it may be advisable to cut out the, diseased spotand paint over the wound with some sort of paint or wash.. When spraying with Bordeaux mixture for other apple diseases if canker be present it would be advisable to thor-t oughly cover the limbs with the spray mixture. BIBLIOGRAPHY.. Beach, S. A., Lowe, V. 1899. Chester, J. D. ., and Stewart, J. C. Apple tree canker. (ppae-opsismalorun Pk.) Bull. N. Y. Geneva Exp. Stat. 170:382 383. Canker inapple and pear.. Rept. Del. Dlxp. Stat. 1900 :43--46. fig. I 1901. 1902. 4-T. Canker in Apples. Bull'. Del.. Exp Stat. 57 :1011. fig. 6. Hall, F. H., and Paddock, W.. 1899. Canker : an enemy of- the apple. Bull. N. Y.. Geneva Exp. Stat. Pop. Edit. 1900. Apple-tree cankers. Stat,. Pop. Bull. IN.-.V'Geneva 1-3. 163 :t-6,. pl. 1-2,. Exp. Edit., 185:1-2-. p1. Paddock, W. 1899. The New York apple-tree canker. Buill. N. V. Geneva Exp. Stat. V-O. pl.. 1 1.63:179% Q. 93 1900. The New York apple tree canker. (Second Report.) Bull. N. Y. Geneva Sxp. Stat. 185:205213. pl 1-4. The New York apple-tree canker. (Second Report.) Rept. N. Y. Geneva Exp. Stat. 19-1900342-350. pl. 53 55. FLY SPECK. 1901. HISTORY AND DISTRIBUTION. This disease, aften referred to as "flies" and "blackbirds," was first reported in scientific literature in 1896 from DelaF ware. It is at present no doubt to be found practically wherever the apple is cultivated. SYMPTOMS. of This fruit disease is marked by the appearance upon the fruit of a number of small spots of specks (Plate II. Fig. 5.) in areas that may be 1-4 of an inch or more in diameter. The skin of the apple around this area may becolne rather cloudy in color and if many of the areas unite with each other the whole surface of the apple may become sooty in appearance. The effects of the fungus do not extend below the surface of the apple, but in the most severe cases the apple may become somewhat shrivelled owing to the action the fungus causing the disease. The claim is made that the disease will spread upon apples in storage. AETIOLOGY. The disease is due to the fungus known as Leptothlyriun~ pomi (Mont. & Fr.) Sacc. 94 RESISTAN CE OP \ AMETIES. This disease appears in ordinary seasons most severely upon the fruit of trees planted in low damp situations. During a very wet:sea.son, 1wever, all sorts of trees will be apt to be affected without to their situation or resistance. Rhode Island Greening, Rome Beauty and Pleasant are very frequently badly injured by this reference Peck's disease.. TREATMENT. One thorough spraying with the ordinary Bordeaux nuxture when, the -apples are half grown or less will prevent the injury fromn this disease. In the case of smooth skinned apples this spraying should be done somewhat earlier to prevent thee so-called "russetting"' of the apples caused by the 'fungicide itself. See also treatment for sooty blotch. Halsted, B.. D. BIBLIOGRAPHY. Decays of Mature Apples. Rept. N. J. Exp. 1893 :367 377. fig. 35-41. Powell, G. H. 1S90. A Fungus Disease of the Apple. Garden and Forest. 1894.. Stat. 9 :474-17 5. Selby, A. D. 1897. my in a wet season. -9. Sooty fungus and fly-speck fungus-an old eneBull. Ohio Exp. Stat. 79: 1900. 133-134. fig. S Sooty Fungus and Fly-speck Fungus. Bull. 'Ohio Exp. Stat. 121 :13--14. fig. 12. / HAIRY ROOT. AND DISTRIBUTION. HISTORY This disease was first reported by Stewart, Rolfs and Hall from Western New York in 1900, but is no doubt much more 95 widely distributed than our records in the literature show. We have here in Alabama a very similar if not identical disease of apple and peach. SYMPTOMS. The affectedtrees have few or no large branch roots. The root system of the tree instead consists of a number of groups of hair-like fine roots springing from the main tap root. Fig. 16 on Plate VI shows one of the common forms of the disease. AETIOLOGY. The cause of the disease is at present unknown. It may be associated with attacks of wooly aphis or with the crown gall, but may occur independent of both of these troubles. It does not seem with us to be found associated with any type of soil. Specimens of this disease are much wanted. BIBLIOGRAPHY. Stewart, F. C., Rolfs, F. M., and Hall, F. H. 1900. "Hairy Root." Bull. N. Y. Geneva 191:300-301. p]. 2. 1901. "Hairy Root." Rept. N. Y. Geneva 19-1900:177-178. pl. 23. (A reprint 191.) RUST. HISTORY AND DISTRIBUTION. " Exp. Stat. Exp. Stat. from Bull. Apple rust is widely distributed and may be expected wherever apples and cedar trees are growing in close proximity to each other. In Alabama the rust is in many sections one of our most serious apple troubles. SYMPTOMS. The disease may readily be detected by the circular yellowish spots (see Fig. 4 on Plate II.) that appear on the 96 leaves in May or June. Similar spotsimay also appear o, ..he fruit. t ,.pring (-kase. apple rust here is produced by one stage of Gym nosporang--tiu utacrop ts, the other stage of which lives on the red cedar causing there the so-called "cedar apples, shown in Fig. 3 on Plate II. The spores produced in the gelatinous out growths from these galils in early are the- source of infection of apple leaves. 'The AETIOLOGY. "Spraying TREATMENT. seems to be of no value in controlling this dis- Since cedar trees harber one stage of the fungus " causing this disease it is of course advisable to remove the _"cedar appless" or if possible the cedar trees themselves, A little attention to this will dispose of he rust ,problem in apple orchards. matter BIBLIOGRAPHY. Wrhester, J. J). 1896. Apple Rust. Rept. Del. Exp. Stat. 8-189-6 63-69. fig. 6-10-. IGalloway, B. T. 1889. Apple Rust. Rept. Secy. 1889:413-414. U. S. Dept. Agr. 1- J aaisted, B.D. Apple Rusts. Rept. U. S. Comm. Agr. 1888 :37381. p1. 1889. 11-1-2. Bull. N. J. Exp., Stat. 86 :15. and cedar apples. 1892. Apple Rust. Jones, L. R. 1891. "Wilcox, Apple rust Stat. Rept. Vt. Exp. 10-1901: 4-1890 :139-140. E. M. Apple leaf rust. Rept. Okla. Exp. Stat. 1901. 116-117. SCAB. H ISTORY AND DISTRIBUTIN. It has been known as a serious apple disease since the early part of the 19th century. For example Curtis recorded it as common on apples in North Carolina in 1867. In this country its greatest injury seems to be in the Mississippi Valley. In this State no definite attempt has ever been made to the writer's knowledge to control it by spraying and in fact it has never attracted any great attention. SYMPTOMIs. Scab first makes its appearance early in the spring soon -after the first leaves begin to unfold. It is during this time that the greatest amount of infection occurs, though there is a second period of infection in the fall which is largely responsible for the production of the mature winter stage. The scab may often be seen on the leaves and fruit of the lower branches showing that the probable source of infection was to be found in the leaves on the ground on which the fungus had wintered over. The first spots on the leaves -are often on the lower side near the midrib-this being the irst part of the leaf to be exposed while the leaf is unfoldlng. ON THE LEAVES. The scab here is found in the form of roundish spots 1-4 inch in diameter. Frequently several of these ,spots may unite with one another-particularly if they are near a large vein or the midrib where the fungus seems te grow more rapidly than elsewhere on the leaf. The spots Ihave an olive green color. :about 98 ON THE FRUIT.. The scab spots are roundish 1-8 to, 1-2 inch in, diameter and of an olive green color-frequently with a lighter colored margin. These spots may coalesce to some extent it conditions are such as to favor the growth of the fungus. The scab fungus grows more rapidly on young fruits than on older ones-due no doubt to the fact that the cuticle of the younger apples is more delicate. Old fruits for the same reason are not very apt to become infected. The cuticle over the "scab" may later in the season become, broken and flaked off, exposing the dead tissues of the apple and giving the scabbed area a reddish brown color. The fungus also frequently causes the formation of a considerable amount of corky tissue-which in turn protects the apple from becoming infected at the scab spot by other, fungi. WVINTER STAGE.I When the diseased leaves fall to the ground in the fall the mycelium that during the summer was confined to the space just beneath the cuticle, grows down into the tissues of the leaf. The deeper penetration into the leaf is made possible by the death of the leaf and the consequent partial decay of its tissues. These hyphae take on a reddish olive color and the cells composing them are larger than those formed during the summer. The fruiting bodies, perethecia, of the fungus are, formed within the leaf. The spores are ripe by April or May and ready to produce the spring nf, ~ton. Per ,hecia are often formed near the small spots on leaves produced by the autumn infection. The pustules are scattered or more generally gathered together in groups on a grayish spot that may mark the spot of the summer's scab. This stage of the fungus is not found elsewhere but on the, leaves. 99 TREATMIIENT. be prevented by spraying with Borden The scab mixture as follows: (1.) Spray with Bordeaux mixture just before the how erbuds open. (2.) Spray again just after the blossoms fall. 10 (3.) Spray 1, 2 or 3 more times at interv ils of days. The following results secured by JcnIes & Orton mont, show the immense profits in spraying for the scab. They spraed as follow~s: 1. April 27. Buds not oeri;with solution of copper, may about inVer- apple, sulfat 1 lb. to 20 gallons. 2. May 118. Leaves out--flowvers not openl; Bordeaux "1 -10" to which was added 1-3 lb. paris green. 3. June .15. Blossoms fallen. 4. July 18. 5. August 3. Comparison' was made of trees sprayed five times and those sprayed three timges (the last two sprayings being here omitted) and trees not sprayed at all. table shows the results clearly : ing The follow- Total value Sprayed 5 Sprayed times Per cent. on the tree. . .. 60 51 Per cent. fallen. 40 49 of crop per tree.. $15.44. Not 3 times 7.382.15; sprayed......... .33 67 ing the disease When account is taken of the fact that the fungus may winter over on the fallen leav'as caus- pears advisable to rake up and burn fallen leaves at they close of the season. The gain from spraying may fall into the following classes : 100 (1.) Actual gain in yield per tree. (2.) An increased percentage of "selects" and No. 1." .apples. (3.) Prevention of falling due to scab. (4.) Increase in vigor of the tree itself. (5.) Reduction of the loss, often very serious, resulting from the attacks of various fungi causing a,rotting about -the scab spots of storred apples. INFLUENCE OF WEATHER. The greatest injury from the scab may be expected during seasons having a cold damp spring. The amount of ~he injury in any given season is also no doubt in a measure .dependent upon the amount of the mature Venturia stage produced on the fallen apple leaves-this in turn being in*fluenced by the climatic conditions prevailing during the preceding fall and winter. AETIOLOGY. Apple scab, a disease affecting the leaves and fruits of the apple, is caused by the parasitic, summer stage, Fusiclcdium dendriticuunt, of the fungus Venturia inaequalis. BIBLIOGRAPHY. Beach, S. A. 1897. Wood ashes and apple scab. Bull. N. Y. Geneva Exp. Stat. 140:665-690. IBlair, J. C. 1899. Spraying apple trees, with special reference to apple scab fungus. Bull. Ill. Exp. Stat. 54:181 -204. fig. 1-27. 'Chester, F. D. 1895. Experiment ih the treatment of apple scab at S. H. Derby's, Woodside, 1895. Bull. Del. Exp. Stat. 29:18-24. fig. 1. 101 Experiment in the treatment of apple scab upon the farm of S.:IH. Derby, Woodside. Bull. Del Exp. Stat. 34 :14-19. fig. 3-4. ;Clinton, G. P. 1901. Apple Scab. Bull. Ill. Exp. Stat. p1. 1-4. fig. 1-34. -Detmers, F. 1891. Apple Scab. (Eitsicladium dendriticmn, Fckl.) Bull. Ohio. Exp. Stat. ii-Vol. 4. No. p1. 5-7. D. G. lendriticat(Wallr.) 1894. Apple Scab. (Fusicladiumc Fuckl.) Bull. Div. Veg. Path. U. S. Dept, 1897. 67 :109-153. 9:187-192. Fairchild, Agr. 6:43 44. ilenderson, L. F. 1899. Apple Scab in the Potlatch. Bull. Idaho Exp. Stat. 20 :77 -95. pl. 1-3. Jones, TL.R. 1891. Black scab of apple. Rept. Vt. Exp. Stat. 4 1890 :142. 1892. Apple and Pear Scab. Bull. Vt. Exp. Stat. 28:30-34. 1892. The prevention of apple and pear scab by spray. ing, 1893. Rept. Vt. Exp. Stat. 5-1891:132- 133. Vt. Exp. Apple Scab. Rept. Vt. Exp. Stat. 6-1892:82-83. Stat. 1894. Apple and Pear Scab. Bull. 44 :83-93. fig. 1-4, 8-9. Jones, L. R., and Orton, W. A. 1898. Spraying for the prevention of apple scab in 1897. Rept. Vt. Exp. Stat. 11-1898:195- 193. illust. 1899. Spraying for the prevention of apple scab. Rept. Vt. Exp. 'Stat. 12-1899 :.156-159. ~Lawrence, W. HI. 1904. The Apple Scabh in western Washington. Bull. Wash. Exp. 4Stat. 64 :1-24 pl. 1. 2 fig. 1-5. 102: Powell, G. II. 1894, The Apple Scab. Gardens and'IMrest. 7:297.. Scribner, F. L. 1888. Apple Scab. Rept...S. Comm.. Agr.1887 :341347. p1. 2. Selby, A. 1). 1899. Apple Scab. Bull.. OhioExp..-Stat.111:95-115. fig. 1-7. Trelease, 1884. W. The apple scab and leaf" blight.. (Fidsicladim dendriticum. Wallroth.) Rept. Wisc. Exp. Stat.. l.45 56. fig. 6-8 . SOOTY BLOTCH.. HISTORY AND DISTRIBUTION. This was first reported by Sturgis' in Connecticut in on Rhode Island Greenings and Newton Pippins. It is now the'fly-speck disvery widely distributed and together ease, with which often associated, causes'luch damage to. apples particularly during wet seasons'or where trees areplanted in low damp soil. 1898" with SY-M PTOM's~. The disease appears as irregular blotches- (Plate II. Fig._ 5.) upon the surface of the apple-these blotches are at first pale, but soon become sooty black color and- under a lens show a radiating appearance due to the manner ofgrowth of the fungus causing the disease. No, rotting ofthe fruit occurs since the fungus works entirely upon thesurface of the fruit. It may with the fly-speck diseasegreatly reduce the market value. of the fruit. in, TREATMENT. both fly-speck and sooty blotch will be controlled' by tlhe- 103 spraying against the scab. It mlay be necessary, however, to give one or two sprayings later in the season, say in July. AETIOLOGY. The fungus causing this disease is geuerally referred to a..P"hyllachora pomigenza, though this matter demands further Ytu dy. BIBLIOGRAPIY. -given (In addition to the following consult the Bibliography under Fly Speck.) each, S. A., Lowe, V. H., and Stewart, F. C 1899. Sooty Blotch. (Phylachora pomigena. (Schw.) Sacc.) Bull. N. Y. Geneva Exp. Stat.'170.388. :Stnrgis ,W. C. 1898. On the cause and prevention of a fungoons disease of the apple. Rept Conn. Exp. Stat. -11897:1171-175. 21- CHERRY. BLACK KNOT. ISTORY AND DISTRIBUTION. Black 'knot has long been known and the extent of its injuries has frequently brought home to and cherry growers in no uncertain ]manner. The plum industry of the famous Hudson river valley (N. Y.) was practically wiped out by this disease. Farlow, 1876, was the 'first to deternmine its exact cause concerning which the most 'various opinions had previously been entertained. 'been plum. 'chierries are by nio means 'exempt. Its most serious injury has frequently been to plums, but DeSchweinitz mentions 104 an epidemic of this disease that destroyed the cherry trees; about Bethlehem, Pa., in 1790. SYMPTOMS. wart-like outgrowth twigs of bark the 18,)' from Fig. (Plate VII. and branches in severe cases extending along thetrunk for several feet. The first symptom is the -swelling of the tissue just beneath the bark. This enlargement increases during the fall or growing season until the bark is ruptured. This exposed portion of the twig is soon covered with an olive green velvety coating composed of thereproductive hyphae of the fungus. A microscopical examination of the diseased portion at this time would show numerous erect hyphae bearing spores-the so-called summer spores. These are readily carried about by thewind and other agencies and serve to spread the disease during the growing season. Later in the season the production of summer spores. ceases and the velvety covering gradually disappears. The surface of the wart gradually becomes hardened and altered in color to a dark brown and finally to a dead black. Pimples may be seen late in the fall covering the wart. In these are developed the winter spores called ascospores. These ascospores only develop during the winter and arecapable of germination in February and March. AETIOLOGY. The black knot is a rough The disease is due to the fungus Plowrightia morbosa. TREATMENT. The diseased twigs should be removed after leaf-fall orbefore the winter spores are formed. Twigs that show in the spring or early summer the beginning of a "knot" should be removed and burned to prevent the formation of the summer spores. If such knots are simply cut off and allowed' 105 ripen audt to remain on the ground the summer spores then be scattered to other trees. Co-operation of entire neighborhoods must be secured tot render the campaign against the black knot effective. Leg islation has been resorted to in several States, but a healthy and intelligent public opinion is necessary in this as im many cases. may BIBLIOGRAPHY. Anon. Black knot of plum and cherry. Plowrightiai. morbosa, (Schw.) Sacc. Bull. N. Y. Geneva, Exp. Stat. 40 :25-34. fig. Bailey, L. H. 1892. The black knot of plum and cherry. The NewYork Law. Bull. N. Y. Cone1 Uxp. Star. 49 -a.)> -454. Beach, S. A. 1894. Some observations on the if- bistor; of Jlow-. rightia ($chw.) Sacc. Rept. N. Y. Geneva Exp. Stat. 1893 :686-688. Beach, S.. A., Lowe, V. HI., and Stewart, F. C. 1899. Black knot. (Plowrightia iniorbosa. (Schw.> Sacc. Bull. N. Y. Geneva Exp. Stat. 170 :431432. Farlow,- W. G. 1876. The Black Knot. Bull. Bussey Inst. 1 :440-454, 1892. 4-10. morbosa pl. 4-6. Humphrey, J. E. 1891. The Black Knot of the Plum. Plowrightia bosa (Schw.) Sacc. Rept. Mass. State. Exp. Stat. )nork, 1890 :200-210. 1893. p1. 1. The. Black Knot of the Plum. Plowrightia maork bosa. (Sz.) Sacc. Rept. Mlass. State Exp. Stat., 1892:235-247. 1)1. 5. 106 iLodeman, E. G. Cherries, and Methods 1894. Black Knot of Plums of.Treatment. Bull. N. Y. Cornell Exp. Stat. 81:633-656. fig. 1-(3. and GUMMOSIS. ,.a Among the stone fruits such as cherry, peach and plum become a "gum-flow" or guimoss.11 is frequent and serious menace to the life of the trees affected. This disintegration of the tissues of the affected plant may be brought about by' a variety of causes. Hence gummosis is 'a generic term applied to the condition here described what,ever be the cause. Massee has described a gummosis of the common flowering almond (Pranus japonica) due to the action of a parasitic fungus, and this seems to be the only case of guminosis so far demonstrated to be due to a parasitic fungus. Excessive gum flow frequently leads to the formation of a canker. (See plum canker, page .) Reports of outbreaks of gummosis in any of the trees mentioned will be gladly received. BIBLIOGRAPHY. MMassee, G. may 1903. Gummlosis of Prunuts japonica (Cladlosporium epiphyllami, Fr.) A Text-Book of Plant IDiseases. 306-310. fig. 82. LEAF SPOT. HISTORY AND DISTRICT. This disease occurs widely distributed on the leaves of ,.cherry, plul and apricot and is frequently referred to as 'leaf blight. 10 SYIIPTOMIS. leaves MIlintie spots at first appear soon after the often oniy 1-6 ncl or less .tre full grown and these are in diameter. On cherry and.plul leaves the spots may have a reddish margin. The spots enlarge to 1-8 inch or more in diameter, (See Fig. 21 on Plate VIII,) becoming at the same time dark and with a pale center. Often the diseased spots fall out of the leaf causing a shot-hole effect and then called "shot hole" disease. (See Plate VIII.) The tree may become defoliated through the action of -this disease and in that case may be much weakened so that it is more apt to be injured during the following winter. The damage in this direction is much greater if the defoliation occurs, as it is apt to in the plum, when the -tree is in fruit. AETIOLOGY. first -This disease is caused by Theleaf spot may be. wxith Bordeaux mixture, -application of the spray ~best time to control time Cyltindrosporiunpadi. TEATM ENT. controlled by the proper spraying but in the case of the cherry the at the time the tree is in fruit, the disease, may cause the fruit to be stained with the spraying mixture so as to reduce its market value. However, it is well apply Bordeaux just before the blossoms open and again just after they fall to partially- control the leaf spot and fruit rot. to ]BIBLIOGRAPHY. iBeacli, S. A. 1894. TPeventing Leaf Blight of Plum and Cherry Nursery Stock. Rept. N. Y. Geneva Exp. Stat. 12189'3:688 693. ph. 5 6. K108 ' Preventing Leaf Blight of Plum and Cherry Nursery Stock. Bull. N. Y. Geneva Exp. Stat.72 :339-346. fig. 1896. Plum Leaf Spot. Bull. N. Y. Geneva Exp. Stat. 98:5-14. p1. 1-5. 1896. Cherry Leaf Spot and Fruit Rot. Bull. N. Y. Geneva Exp. Stat. 98:15-17. pl. 1-5. 1897. Plum Leaf Spot. Rept. N. Y. Geneva Exp. Stat.. 15-1896:384-401. pl. 25-29. 1897. Prevention of Fungous Diseases in Cherry chards. Rept. N. Y. Geneva Exp. Stat. 15-1896 402 407. Duggar, B. M. 1899. Notes on the Shot-hole. Effect of Peaches and Plums. Bull. N. Y. Cornell Exp. Stat. 388. fig. 71-72. Fairchild, D. G. 1892. Treatment of plum leaf blight in nursery., rows. Bull. Div. Veg. Path. U. S. Dept. Agro. 3:63 65. 1892. Treatment of plum leaf blight in the orchard. Bull. Div. Veg. Path. U. S. Dept. Agr. G-M3.. 1893. Plum leaf-blight. (Cylindrosporium padi' 1894. 1-2. Or- 164:385- 3:62' Karsten.) Journ. Mycol. Journ. Mycol. leaf-blight. p1. 7:253-255. pl. 28-29., padk' 1893. 1893. Cherry- leaf- blight. Karsten.) Plum (Cylindrosporiumn 7:249-252. p1. 26-27.. (Gylindrosporiunt pads' (Gylindrosporimmn padi' Karsten.) Rept. N. Y. Geneva Exp. Stat. 11-- 1892:659-662. 1893. Cherry Karsten.) Rept. 27-28. Y. Geneva Exp. Stat. Leaf-Blight. N. 1892 :654-659. pl. 25-26. 11- 1894. Plum' Leaf Blight. (Gytindrosporium2 padh' Karst.) Bull. Div. Veg. Path. U.. S.. Dept. Agri, 6:39-40. 109 Green, W. J. 1891. The "shot hole" fungus of the plum. Bull. OhioExp. Stat. ii-Vol. 4. No. 9:216 217. Thaxter, R. 1891. Leaf Spot of Plums and Cherries Causing Defoliation. Rept. Conn. State Exp. Stat. 1890:102. PEACH. BROWN ROT. HISTORY AND DISTRIBUTION. It has been known as a serious enemy of the peach in the United States for over 20 years and in Europe for even longer. Whenever peaches, plums or cherries are grown in this country the brown rot is a most serious pest. During certain years the loss is made most noticeable by favorable weather conditions. Thus in 1900 the loss to the peach crop, in Georgia was estimated to be 40 per cent. or from $500, 00 to $700,000. Similar losses are reported from otherplaces. In Kentucky it has been reported as a rather serious disease of apples, but with us it seems to be confined to the peach, plum and cherry. It has also been reported on the pear; quince and apricot in addition to the above.. SYMPTOMS. ON THE FLOWERS. Under favorable climatic conditions the disease may attack the flowers before or after the petals have fallen. At first a slight discoloration will appear onsome part of the flower and soon this spreads so as to givethe whole flower a brown and withered appearance. In Alabama during 1897 an epidemic of this disease of thepeach flower appeared that practically destroyed the peach 110 crop for that season. Foggy, rainy and very warm weather were the conditions then prevailing that made possible the germination of an unusual number of the spores, derived, as usual, from the old diseased "nmummy" fruits adhering to the trees. The spores formed on the diseased flowers were then sources of infection for any fruit that was later developed. ON THE TWIGS. On the peach and plum, particularly the peach, the mycelium of the fungus may grow down into the twigs from flowers or fruits that are infested. This condition of affairs is often referred to as the "twig-blight" of the peach. ,(See also canker of plum on page 131.) If only one or two peaches are found on a twig the twig is apt to become infected at only one point and thus be girdled by the fungus, resulting in the death of the uninfested terminal portion of the twig. If several infested fruits occur on the twig it anay become infested throughout its entire length. the ON ''TIE FR.UTT. Small brown spots appear-these rapidly enlarge and whitish tufts of spore-bearing hyphae may appear. The peach may fall to the ground or simply shrivel up and remain attached to the tree. (See Plate III.) In the case of the plum the fruit may be infected for some time before any external evidence appears. As the plum begins to ripen, however, the ash grey tufts of sporebearing threads appear. This difficulty of distinguishing between infested and healthy plums leads in many cases to serious losses in shipping these fruits. Peaches also often suffer en route to market from this rot particularly if the refrigeration is not properly attended to. 111 TREATM ENT. The brown rot can be effectually controlled by two lines of treatment: (1) spraying with Bordeaux mixture as explained below and (2) removal and destruction of all affected fruit from both the tree and the ground. The trees should be sprayed with the Bordeaux mixture as follows: 1. 2. 3. Just before the buds open. Just after the blossoms fall. Ten days to two weeks later. 4. Keep the fruit covered with the Bordeaux mixture until ripening begins and then employ either the ammoniacal copper carbonat or a solution of dibasic copper acetat made by dissolving six ounces of the salt in fifty gallons of water. These two mixtures will not injure the fruit. Too much stress cannot be placed upon the absolute necessity of removing from the tree all the diseased fruits since these are sources of infection and their presence upon the tree may lead to most severe attacks of the twig disease produced by this same fnngus. The fruits that are allowed to fall to the ground after rotting may serve as the home of the perfect stage of the fungus and act as sources of infection during the next spring. Mummy fruits (Fig. 8 on Plate III.) should not be allowed to remain om the tree. AETIOLOGY. The brown rot is caused by the fungus now.r known as Sclerotinia fractigena-the conidial or imperfect form of the fungus, however, known as Monilia fructigena, being the direct cause of the disease. The perfect form of the fungus has been found on old fallen peaches in Maryland and Georgia. Its discovery emphasizes the necessity of removing and destroying all fallen and mummy fruits. 112 J_ ester, 1892. . (Thin . Peach Rot be Controlled by Spraying? preliminary report. Bull. Del. Exp. Stat. 1-16.l1fig. 189:3. 19 A Can peach rot be controlled by spraying A prelilinary report. Rept..Del. Exp. Stat. 53-613. 1 fig. 189 7 . Experiment in the Treatment of Peach Rot Upon the Farm of J. W. Killen, Felton. Bull. Del. Exp. Stat. 34:4-1.3. fig. 1-2. :d-Cordl~ev, A. B. 1899. Brown Rot. Bull. Oregon Exp. Stat. 57 :1-i. lpl.fig.l1 7. Galloway, B. T. 1889. Brown Rot of the Cherry. Monilia frictigena. P'ers. Rept. U. S. Commn. Agr. 1888:349-352. p1. 5 6. Garman, 11. 1890. The brown rot fungus of plums, peaches, ples and cherries. (Motiia fractigcna. Pers.) Inept. Kcy. Exp. Stat. 2-1889:31-42. fig 9-12. 1893. An experiment on plum rot. Bull. Kyi. Stat. 47 :53-.551. fig. 15. Also Rept. Ky. 15xjp. 1892: ap- Exp. Newman. 1902. Slat C. C. 6--1893 :130 131. fig. 15-1894. Brown Rot of Peaches and Plums. Bull. S. Gar. Exp. Stat. 69 :1-12. p1. 1-3. Qtnaintance, A. 1L. 1.900. The Brown Rot of Peaches, Plums and Other Fruits. Bull. Ga. Exp. Stat. 50 :233-2,69. fig. 1 -9 ~mith, E.F. 1892. " Peach Rot Journ. Mvcol. 7 :92. .Townsend, C. 0., and Gould, H. P. 1901. Notes on Spraying Peaches and Plums in 1909. Bull. Md. Exp. Stat. 71:115-127. 113 CROWN GALL. HISTORY AND DISTRIBUTION. "Crownn gall is a contagious disease affecting a considerable number of the smaller and larger fruit trees and plants. "The disease has been reported upon the following plants: peach, almond, apricot, prune, plum, pear, apple, English walnut, raspberry, blackberry, cherry, poplar and chest,nut. It is, however, not at all certain that the galls on all the above plants, though very similar in general appearance, caused by one and the same organism. -are SYMPTOMS. The gall generally behaves as an annual growth-those 'that begin in the spring mature the same fall. But in this 'climate the galls that start in late summer or fall continue their growth through the winter season. It is strictly a !nursery disease-seedlings 1 to 6 months old being most likely to become infected. The first gall in such cases genterally appears on one side of the main root a few inches 'below the surface or near the "crown" of the seedling. On larger trees the galls genrally appear on the lateral roots though the crown is also commonly attacked in the case of large trees. (Plate V.) The wart at first is a light colored clear or translucent mass of succulent tissue frequently attached to the plant by means of a slender stalk or neck. The galls grow very rapidly and the outer surface soon takes on a warty appearance and a reddish brown color. The parts of a gall that become dark colored have lost their power of growth the discoloration being due perhaps to the action of various fungi attacking the gall. From the surface of such a discorored gall many new smaller outgrowths may appear. Toward the end of the season the gall becomes badly de,cayed and may readily be broken away from the plant leav- 114 ing an ugly deep wound. 1)uring the following spring new lot of gall growth may take place around the margin of the old scar. And if the gall be removed new growth may begin even in the center of, the wound thus formed. (Fig.. on Plate V.) This process, may continue u til the resulting wound is so. deep that the tree falls of its own, weight. If a section of rapidly growing gall be examined there will frequently be found through it numerous darker col ored irregular spots that are centers of more rapid growth. These centers frequently become beautifully twist ed nodules of woody tissue after the gal matures and be gins to decay many of thes curious nodules may readily b& removed from the outer portion of the gall. a 14 SPREAD OF TH DISEASE. The disease has been widely scattered over the countryby shipments of stock from infested nurseries. Locally it is known that a single diseased tree may in a few years suffice to infect most of the trees in the orchard.. The spores of the parasite are mna1l and may be carried by the air and it is likely that the diseasenmay be munnicated com- from old decayed galls. in the The careless wounding of the crown of a tree or the bark produced by escaping "suckers" both make a. break pathway for the parasite to gain entrance into the tree.. Care should in all cases be' taken to see that all removed galls and uprooted diseased trees be burned on the, spotand not hauled through the orchard all. at AETIOLOGY. Tfoune~y in Arizona gave special attention gall on the almond described as the cause of this dis ease a new species of slime mould which he called Devd'ro-. phagats and -to thet crown globosus. As has been said it has never been demon-_ strated that this organism1 is the cause of- the widely dis=~ li5 tribnted crown gall on the various plants that were men. tioned above, Tourney was able to communicate the mond disease to the peach and apricot, but failed to do so to the apple. Selby believes that the gall may be corn, municated from the raspberry to the peach, bnt ialsted came to the opposite conclusion. Much work remains to be done on this very important disease. al- TREATMENT. The best advice that can be given fruit growers relative. never plant trees from a nursery known to be infested with the disease and never plant trees showing the disease. if a diseased tree is planted it is practically certain that the tree will never amount to anything. And what is even iuore important one is thereby very likely to introduce the disease into the soil of the orchard. If a bundle of nursery stock has a single crown gall on any of the trees the whole lot of trees should be destroyed. it is possible that some good may be done by inspecting the orchards annually and removing all galls that have formed at the crown of the trees. After carefully cutting away the gall the wound surface should be covered with a paste made of lime and blue vitriol. But it inust be remembered that, though the galls at the crown do the most danm age, the smaller galls on the roots, which cannot be removed after planting, will reduce the vitality of the tree to the crown gall is this It is therefore certaint hat no amount of after treatment of any sort will make a diseased tree give as large a yield as a healthy one. BIBLIOGRAPHY, Alwood, W. B. i903.* Some observations on Crown Gall Trees. Bull. Va. Exp. Stat. 27--37. 140 :185-2i2. of Appt;l e fig. 0 This Bulletin is marked "September. 1902," on the front covert but on the last page are the xv)rds '1ssue&1 September 15, 1903." 116 Ii addock, W. 1903. Crown gall. Bull. Col. Exp. Stat. 1-3. #Selby, A. D. 1898. Crown Gall of the Peach. Bull. Ohio Exp. Stat. 92:208-217. ph. 5-6. 1899. Communicability of crown gall. Bull. Ohio Exp. Stat. 104 :211. 1900. Crown Gall. (Apple.) Bull. Ohio. Exp. Stat 1.21 :13. fig. 11. 1900. Crown Gall. (Peacl.) Bull. Ohio Exp. Sta. 121:43. fig. 35-36. 1900. Crown Gall. (Pear.) Bull. Ohio Exp. Stat. 121: 48. fig. 41. 1900. Crown Gall. (Plum.) Bull. Ohio Exp. Stat. 121 :48. zSmith, E. F. 86 :1,-8.-ph 1894. Stem and -root tumors. Journ.Mycol. 7 :376 -377. pl.. 38. "Toumley, J. XV'. 1900. An Inquiry into the Cause and Nature of Crown Gall. Bull. Arizona Exp. Stat. 33 :1 64. _f-g. 1-31. 1 plate. LEAF CURL. HISTORY AND DIsTRIBUTIoN. The leaf curl of the peach is found practically wherever the peach is cultivated is one of the most serious of 'all peach enemies. The total losses from curl in the whole United States have been estimated by Pierce to be as high ~a3000,000.00 in a,single year. and SYMPTOMS. As soon as the young leaf buds begin to open the leaves 117 the characteristic roughened surface and deeper green color. This "curling" of the leaves progresses rapidly as the leaves grow (Fig. 9 on Plate IV). A part only or all of the leaf blade may become affected. A mature leaf, affected with curl, may have a reddish color, but generally the diseased leaves become simply discolored. The fungus also grows inside the terminal portion of the young twigs and causes these to become swollen and to take on a lighter, paler color. These swollen terminal portions the twigs constitute the only home of the perennial portion of the fungus. The spring infection seems to take place largely from spores formed from the mycelium present in these swollen twigs. The leaves soon become covered with a greyish mealy coating-composed of the fruiting bodies of the fungus. The spores are produced in small sacs arranged parallel to each other and at right angles to the surface of the leaf. These asci are produced on the ends of hyphae that grow out through the epidermis of the leaf. Defoliation occurs soon after spore-formation. Gummosis of affected twigs is frequently to be seen as a result of the action of this fungus. The tree attempts to make up for the loss of leaf surface by forcing some of its dormant buds to grow-these buds mnay grow to give a healthy twig but at the base will be left the swollen fungus-infested portion-constituting a dangerous source of infection for another spring. fhow ,of RELATIONSHIP TO THE WEATHER. The epidemic character of leaf curl has been frequently noticed and attempts made to connect the sporadic char- acter of the disease with some climatic factor. No very definite statements can be made further than the suggestion that the phenomenon referred to can perhaps best be explained as due to the influence of certain climatic factors upon the spores either at the time (a) they are being scattered or (b) during germination and infection of the tree. 118 TRAm1ENT:'. Leaf curl may be prevented by (1.) Spraying with Bordeaux just previous to the open ing of the buds in the spring. (2). Spraying 'again with weaker Bordeaux as soon as the petals of flowers have fallen; this is to prevent late infection from the ground or neighboring trees. (3.) Spraying again with weak Bordeaux when the first leaves are full grown or when the spores of the fungus developing. This is to prevut summer infection and cover places where spores lodge to pass over the winter. Where inter spraying against San Jose Scale with the lime-sulfur-salt wash is conducted this treatment may suf. fce of itself to hold the curl in check. are may BIBLIOGRAPHY, Atkinson, G. F. 1894. Leaf Curl and. Plum Pockets. Contribution to of the. knowledge of the Prunicolous United States. Bull. Cornell Exp. Stat. 73. Exoasceae Duggar, B. M. Peach Leaf Curl and Notes on the Shot-hole Effect of Peaches and Plums. Bull. Cornell Exp.. Stat. 164 :367-388, fig. 64- 72. Murrill, NV. A. 1900. The Prevention of Peach Leaf-Curl. Bull.. N. Cornell Exp. Stat. 180 :319 -334. Pierce, N. B. 1899. Y. 1900. Peach Leaf Curl: Its Nature and Treatment. Bull. Div. Veg. Phyvs. and Path. U.. S. Dept. Agr.. fig. 20 :1-204. pl. 1-30. 1-to. Bull. Ohio 1Pip. Siat.. Selby, A.. D. 1898. Leaf curl of the peach. 2:~226-231. p1. 84 119 1899. Further studies upon spraying peach trees and upon diseases of the peach. Bull. Ohio Exp. Stat. 1041:199-216. p1. 1-3. 1899. Variations in the amount of leaf curl of the peach (Exoascas dfo noccfls) in the light of weather conditions. Proc. Soc. Prom. Agr. Sci. 1899 :98-104. 1904. Peach Diseases iii. Bull. Ohio Exp. Stat. 148 53 67. p1. 1 7. ROSETTE, HIsTORY AND DIsTRIBUTION. ,but The rosette is known from a few stations in the west, is principally known from Georgia and a part of South Carolina. - It is found in peaches and almonds and perhaps also in plums. It seems not to have attracted much atten tion in Georgia until about ten years ago, but is now known to be present in many counties in budded and seeduing orchards and also in seedlings growing in out of the 'wvay places. SYMIPTOMIS. The rosette is in some respects closely related to the 'lows. It may attack only parts of the tree at first, but may appear suddenly in the spring attacking nearly the whole tree at once. In such cases all the leaf buds grow out into compact tufts of leaves or rosettes, whence th'e name. Fig, 10 on Plate IV shows some of these characteristic rosettes. If a tree is attacked all over it will die the following au,tumnn, but if only one or more branches are attacked then only the diseased branches will die after a period of about six months. The leaves in these rosettes are gem. erally of a peculiar yellowish color. The lower leaves in the rosette are frequently much larger thali the normal yet. first 120 leaves and have inrolled margins and are stiffer than the asual leaves of the peach. These outer larger leaves turn yellow and fall early in the season while the inner leaves are still green. If a tree is attacked in all parts it bears no fruit, but otherwise the fruit born will generally be apt to shrivel up while still green and fall off or it may ripen naturally. The disease may be spread through budding or root grafting as has been demonstrated by many experiments. How ever, it is known that mere contact of diseased with healthy tissue is not sufficient to introduce the disease, but there must be a real union of the two tissues. AETIOLOGY. Like the yellows the exact cause of rosette is yet unknown. TREATMENT. All trees which show the rosette in the spring should be at once dug up and burned. If any of the diseased leaves have fallen these should be gathered also and burned as. they may serve as sources of infection. BIBLIOGRAPHY. Johnson, W. G. 1896. Peach Rosette. Bull. Md. Exp. Stat. 42:160162. fig. 7-8. Selby, A. D. 1898. Rosette. Bull. Ohio Exp. Stat. 92:199. Smith, E. F. 1891. Additional Evidence on the Communicability of Peach Yellows and Peach Rosette. Bull. Dept. Agr. Veg. Path. 1:1-65. pl. 1-38. 1894. Peach Yellows and Peach Rosette. Farmers, Bull. 17:1 20. fig. 1 7. 121 YELLOWS. HISTORY AND DISTRIBUTION. This distinctly American disease is known to affect, int addition to the peach, the almond, nectarine, apricot and plum. It seems to be widely distributed in the United States. SYMPTOMS. "Prematurely ripe, red-spotted fruits, and premature unfolding of the leaf buds into slender, pale shoots, or into.. branched, broom-like growths, are the most characteristic symptoms of yellows." The reddish spots in the fruit extend from the skin to the stone and their presence is oneof the best tests for the disease. During the first season that the disease is present in any given tree it may confine its attacks to one or a few only of the branches, but in later years other symptoms may appear and these are principally the premature opening of the winter buds. This is most plainly seen in the fall after the tree has lost all its leaves. The shoots may at this tinie be produced from these prematurely opened buds and are then very conspicuous. Very feeble shoots may also appearon the larger branches of the tree and these also are rather conspicuous on account of their broom like appearance. In the later stages of the disease or when the disease has been present in a tree for several years the yellowing of theleaves may become apparent and this condition has given rise to the common name, but this is not the most conspicuous symptom and has led many to confuse the disease, with leaf curl and other diseases. AETIOLOGY. The exact cause of the disease is not yet known, though it is generally looked upon as a so-called "physiological dis_ 122 ease." As to its spread and its infectious nature we are certain. It may be present in a dormant condition in buds employed in the nursery for budding and the disease is often introduced into a new region in just this manner. The disease is also known to be spread from living and dead trees affected with the disease to healthy trees in the same orchard. Soil and climatic conditions certainly cannot be charged with the cause of a disease which possesses such an infee-tious or contagious nature and there is no good evidence to show that the disease is caused by bacteria or other vegetable organisms. TREATMENT. The only line of treatment that promises to control the disease is to dig and burn the roots and entire tree as soon as it-shows certain symptoms of this disease. Spraying is of no value and special fertilization of the soil seems to be of no value in its control. "Pits" or seeds from disjeased trees should never be employed in a nursery or elsewhere. BIBLIOGRAPI Y. Bailey, L. II 1890. The Peach Yellows. Bull. N. Y. (Cornell) Stat. 25:178-180. 1894. Peach Yellows. Bull. N. Y. (Cornell) Stat. 75:389-408. 8 figs. Beckwith, M. H. 1894. Are Seedling Peach Trees Exempt From lows? Rept. Del. Exp. Stat. 6-1893:152. Chester, F. ). 1890. Peach Yellows. Culture Tests. Rept. Del. Exp. Exp. Yel- Exp. Stat. 2-1889 :9g-94. Johnson, W. G. 1896. Peach Yellows. Bull. Md. Exp. Stat. 42:157160. fig. 5-6. I2 1890. Some observal ions on peach yellow-s. Mass. Hatch Exp. Stat. 8 :6 12. fig. Powell, G. H. 1897. Peach Yellows in Nursery Stock. Rept. 1)ll. Exp. Stat. 9- 1897 :168 173. fig. 1-5. 'Selby, A. D. 1896. Peach Yellows. Bull. Ohio Exp. Stat. 72 :193-. 206. fig. 1-5. pl. 1. Ohio Exp. Stat. 92:190 1898. Peach Yellows. 199. fig. 4-5. p. 1 2. Smith ,E. F. 3u1., a Preliminary Report. 1888. Peach 9:1-254. ph. 1-37.. Div. Bot. IT. S.Agr. 1-6. Huit. Bull. Yellows: 1891. Additional evidence on the connnunicability of peach yellows and peach rosette. Bull. Div. Veg. Path. U. S. Dept. Agr. 1 :11 65. pl. 1-38. 1893. Experiments with fertilizers for the prevention and cure of peach yellows, 1889-92. Bull. Div. pl. Veg. Path. Bull. U. S. Dept. Agr. 4 :1-197. Rosette. 1-33, -1894. Peach Yellows and Peach fig. Farmers' 17:1-20. L) -C II /\ 1-7. PEAR~. BLIGHT. HISTORY AND DISTRIBUTION. Pear blight, called also twig blight, and fire blight,- is a centagious bacterial disease of pear, apple, quince and other pomaceous fruit trees. It is of very wide distribution and may be found practically throughout the United States east of the Mississippi river. It has been ascribed to the most 12. various causes, but the complete demonstration of its bac terial nature was made by Dr. Burrill, of Illinois, in 1879,. SYMPTOMS. This disease attacks the flowers, young fruits and the young twigs and shoots, frequently working its way down through the bark to the larger limbs or even to the trunk itself. The disease has its most prominent symptom in the blackish discoloration of the leaves on the attacked twigs, but the bacteria do not as a rule find their way into the leaves except into the petiole and the larger veins. This discoloration of the leaves occurs in a week or more afterthe death of the branch on which they are found. (See Fig. 15 on Plate VI.) There is much variation in the manner the attacked plant behaves or rather in the way the disease works. In some cases the affected twig is simply girdled and in that case the damage is not so great as when the whole twig or branch is killed. The very sudden death and rapid discoloration of the leaves has led many to suppose that the disease spreads in the tree more rapidly than it actually does. As a matter of fact the disease does not spread more than 2 to,10 inches per day in the twigs. In the spring the blight first makes its appearance in th& blossoms causing there the so-called "blossom blight." The most rapid distribution of the disease in the orchard takes place while the tree is in bloom. It is now known that the principle agency in this work is the various bees that visit these flowers for the nectar there found. In this nectar. the bacteria causing the blight find a most suitable situation for rapid development. Bees going from flowers whose nectar contain even a few of these bacteria to healthy flow, ers on the same or other trees are very apt to carry some of the germs and thus rapidly spread the infection. The disease also gains entrance to the plant through the tips of young shoots or twigs. This form of blight is often referred to as twig blight. In the case of nursery stock 125i not in flower the disease is more often carried about in this manner. AETIOLOGY. Pear blight is now known or us, one of the bacteria. 1879 by Dr. T. J. Burrill. Lion experiments this has been demonstrated beyond-a shadow of doubt. There can never be any blight in the absence of this species of bacteria, no matter how very favora ble soil and climatic conditions may be. It was once supposed that the germ might live over winter in tie ground, but that is now known to be false. As a ruleh the blight ceases at the close of the growing season, but some cases, particularly where new infection has taken place late in the season, the germs may live over winter in. the twigs and slowly push out into the healthy bark during the winter. The blighted twigs hold their moisture longer than healthy twigs and this is naturally very favorable to the germ and besides it is known that the germ may be exposed to a freezing temperature without injury. to be due to Bacillusam yto_ This discovery was made By means of the usual inocula- inf in In the spring the rapid accumulation of sap in the twigs sets up a flow of gum from the twigs in many cases and if,( the germs are alive in any of the twigs they are naturally carried out by this gums flow. Bees and other insect s- are attracted to this guns and by this means the germs are carPied to at which poimnt they rapidly multiply in the Y nectar and enter the twig. flowers INFLUENCE OF ENVIRONMENT U PON .TIE DISEASE. warm moist The pear blight makes best 'headway during weather and is more or less weather. old, dead and dry twigs the germs will dlead. cold, dry and sunny The germ is very sensitive t4 dryness in the retarded by 1l be and found to be 126 J)isea se resistant sorts- Such sorts the and Duchess resist the bIight the IIartlett and some others and general the apple is much less injured by the disease than are the pear and quince. There seems to be no need of attempting to breed special resistant sorts when we considel the positive reiiedial measures mention below. more than as Keifter in 1.'uti vtion anlld soil ferlilit- v 11n general may state that a well cultivated, highly -fertilized and rapidly growing tree is most to be attacked by the blight. Trhe use of too much barnyard manure is particularly dangerous if the soil is already rich in nitrovenous matter. In some cases it may be well to avoid too excessive cultivation. In general measure that will tend to check the too rapid growth of the tree will tend at the same time to protect the tree against the blight. Heavy pruning in the winter time, since it promotes rapid of much new wood in the spring, also be at timies with good results. we apt any tion may avoided forma- Treatmenct The absolute (lestruc ion of every blight germ should be aimledlat and may lbe secured by the pinning away and de- t structioii of each and every blighted twig as soon as detected. These may be. renmovedl during the growing season, bult it is best to do this very thoroughly at the close of th-e :*groving season, but before the leaves have fallen. blighted leaves will then serve as a guide. Most careful inns pection of the trees must be made during the winter and again early in the spring before new growth starts to make The sure that no cases of living blight are allowed to remain ini the orchard. that are This is important since these cases of blight allowed to live over winter are the only starting i-points for new infection in the following spring. 127 BIBLIOGRAPHY . Alwood, W. B. 1903."* On the Occurrence and Treatment of Fire Blight in the Pear Orchard. Bull. Va. Exp. Stat. -66. fig. 1.6-20. Chester, F. 1). 1901. Notes on Pear Blight. Rept. Del. Exp. Stat. 12-1900 :3-43. fig. 1-3. 1901. Pear blight and pear canker.. Bull. Del. Exp. Stat. 52:1-S. fig. -T. 7 Butt, W. N. 1908. Pear Blight. Bull. Utah Ex. Stat. Waite, M. B. The cause and prevention of pear blight. Yearbook IT.S. Dept. 1895295300.. 135:49 85:45-0 1896. Agr. within containS the statement, "Issued June 3D. 1903." *This Bulletin bears on the outside the date, April,.190?,.but LEAF BLIGHT.. HISTORY AND DISTRIBUTION:.. This disease has long beeni known to lhorticulturists as thea "leaf blight" or of pear anid as- the "cracking" of fruit. It occurs practically wherever the pear is cultivated. It. was mentioned in this country early in sixties. "scald" the the, SYMAPTOMS, Time prominent quent symptoms are the premature, discoloraThis leaf faill may be sudden lion of the leaves and their fallinig off together with the fre- cracking of the fruit. or imore gradual, extending in thme latter case throughout the, growing season. Often tlhe leaf fall is accompanied with aZ second blossoming both together making a rallher Severe dra in upon the food sup~plies of thme free. 1 28 Small reddish spots are first seen upon the leaves; these spots as they increase in size take upon themselves a more definite circular shape. At nlatrity the spots are provided .with-a whi te to reddish brown ((ter and a darker raised border. The spots may unite with each other and thus the whole leaf may become affected. The spots may come to be seated upon a reddish brown discolored leaf or the leaf .may turn yellow. In any case the leaves fall from the tree. In many cases there is also a so-called "cracking of the pear" produced by the same fungus. Small reddish spots .appear upon the fruit and these spots rapidly increase in number and coalesce with one another to give the fruit a very much blotched appearance that will greatly reduce its market value. the same time the growth of 'the spots may be accompanied by a cracking of the fruit 'and of course this cracking may make an entrance for the spores of the rot fungi that may cause much damage. The same fungus often attacks the young twig of the pear. T1 e 'spots upon the green bark of these twigs are somewhatelon .gated, sunken and of a black color. In each of the spots referred to above on either the leaves, fruits or twigs one may see oie or more blackish spots just beneath the surface. Thmese spots the spore productung bodies of the fungus. The petioles and leaf scales are also frequently attacked. finally may At are AETI OLOGY. This disease is produced by the fungus Emtomospor-ii Sl? (1cu lat Ufl. TREATMENT. Fallen leaves should be gathered together and burned. The disease may be controlled by spraying with Bordeaux 'm-ixture, as follows: (i_.) 'When leaves are half grown. 12 '(2.) Three subsequent sprayings at intefyals of two weeks. The sprayings after the second should be made with amTuoniacal copper carbonat to avoid the "russetting" injury to the fruit often produced by the Bordeaux mixture. BIBLIOGRAPHY. Chester, F. I). 1891. Experiments in the Treatment Quince Leaf Blight. Rept. Del. Exp. of Pear Stat. and 3- 1890:69-77. fig. 3-6. 1891. The treatment of the leaf blight of the pear and quince. 1892. Entomiosporiumbmacmultai, Lev. Bull. Del. Exp. Stat. 13 :4--16. fig. 1-3. 2 plates. Present status of knowledge on the treatment of pear leaf blight. Rept. Del. Exp. Stat. 4 1891 :44 47. ~Duggar, B. M. Some Important Pear Diseases. Bull. N. Y. Cornell Exp. Stat. 145 :6t1 615. 'Galloway, B. T. 1892. Experiments in the treatment of pear leaf blight, cracking, and scab. Bull. Div. Veg. Path. 1898. fig. 166-167. Southlworth, E. A. 1889. Leaf Blight and Cracking of the Pear. En tomtosporiunt ,niaculatuqn, Lev. iRept. U. S. 864. p1. 1888:357' 8-9. Comm. Agr. Waite, M. B. 1894. Treatment of pear leaf blight in the orchard. Journ. Mvcol. 7 :333-338. SCAB. pl. 3.2-33. HISTORY AND DISTRIBUTION. The scab of pear is, like the similar disease of apple, ver-y 130 widespread and well known. It is known from practically every region where pears are grown, SYMPTOMS . The symnptoms are practicallv the same as for the applek scab. (See page 97.) AETIOLOGY., This disease is due to the fungus called Fasicladaiw AT TPTI M U'NT. The diseased leaves should be plowed-under or else gath ered together and burned during the fall. Two sprayings with Bordeaux mixture of the 1-10 formula should be made while the pear leaves are opening. Considerable good in controlling pear scab will result from a ing with the lime-sulphur-salt mixture as late in the winter, spray- as possible. BIBLIOGRAPHY. Beach, S .A. 1894. Experiments in preventing pear scab. Rept. N., Y. Geneva Exp. Stat. 12-1893 :694 717. pl., 7-8. 1894. Experiments in preventing pear scab in 1893x4. Bull. N. Y. Geneva Exp. Stat. 67:183 204. fig. 1-2. Galloway, B. T. 1892. Experiments in the U. S. Dept. Agr. 3 treatment of pear leaf- blight, cracking, and scab. Bull. Div. Veg. Path., :36-47. Sturgis, W. C. 1894. Spraying for "~Scab" of Apple and Pear. Ilept". (Conn. Exp. Stat. 17-1893 :72 7 3. 131 1895.. Experiments -on the treatment of pear scab.. Fasicladiuin pirinn im. Lib. (Fckl.) Rept. Conn. Exp. Stat. 18-1894 :135-137. Smith, R. E. .1905. Pear Scab. Bull'. Calif. Exp. Stat. 163:1-18., fig. 1-9. PLUM CANKER. HISTORY AND DISTRIBUTION. This disease is one of the most serious plum diseases we have to contend with in 'this State. Its distribution is some what uncertain. SYMrPTOM S. The real canker may be preceded by a gummosis. (See Gummosis under Cherry on page 106.) And this gummosis may be due to one of several causes. But when through gummlosis or any other cause wounds of plum trees remain for a long~ time unhealed a cankerma form on the twig. It is probable that aside rot fungus. from wounding the most fre- quent source of the trouble is to be found in the attacks of the brown (Sclcrotinia fractigenat.) This fun- gus, as has been explained, works in the tissues of the, twigs, particularly the fruiting spures, and finally kill such parts. Then gunimosis sets in to be followed soon by the canker. The canker may also follow severe attack,. of plum pockets. The Japan plums, being very subject to brown rot, au d having soft coarse grained wood, are very apt to succumb to_ this canker. 'may 132 TREATM ENT. rrhe only treatment to be recommended consists a thoroughi spraying to prevent the brown rot and pockets; and then the removal and bnrning of the cankered 'limbs. BIBLIOGRAPHY. plnm in 'Selby, A. D. 1897. A twig disease with gnm flow. Bull. Ohio Exp. Stat. 79 :121-122. fig. 4. Waugh, F. A. 1901. Plnm Tree Canker. Dept. Vt. Exp. Stat. 13 1900:370---373. 1 fig PLUM POCKETS. HISTORY AND DISTRIBUTION. This disease on account of its very characteristic and striking symptoms has long been'known to horticnhtnrists and others. It is very widely distribnted thronghont the United States and has freqnently been forwarded to mne from varions parts of this State. SYMIPTOMIS. The vegetative portion or mycelinm lives over. winter in the younger twigs and grows ont into the developing ovaries in the spring. All or most all of the parts of the ovary are affected and the action of the fnngns is to greatly stimnhate the tissnes of the ovary so that a very rapid growth takes p~lace. The resnht is a mnch swollen, somewhat Irregnlar and spongy body of light yellowish or white color (Fig. 17 on Plate VII.) No stone is developed in this "plumpocket" bnt the- center is hollow or frequently traversed by ]oose threads of torn tissue. 1133 The leaf buds and young twigsiuay also become modifl ed by the action of this fungus to form very;rregu !a 8pongy swollen objects. In this case the resulting hypertrphy varies with the stage at which the fungus begins its work. If the leaves are not far developed when attacked t heir normal form may never be attained, but the hypertrophy may affect only a portion of the leaf if its attack is 'made upon the leaf when partly grown. disease is produced by the fungus Exoascus pruai a species somewhat closelyrelated to the one causing the deaf curl of the peach. TREATMENT. '-This AETIOLOGY. No special spraying treatment can be reconmended, though the use of Bordeaux mixture would no doubt reduce the chance of infection. Diseased fruits, buds, leaves and Iwigs should be removed and burned. BIBLIOGRAPHY. .Atkinson, G. F. 1894. Leaf curl and plum pockets. Contribution to the knowledge of the prunicolous Exoasceae of the United States. Bull. N. Y. Cornell Exp. Stat. 73-:329 330. "Galloway, B. T. 1889. Plum Pockets. Taphrina pruni, IRept. U. S. Dept. Agr. (Fckl.) p-. -10. Tul. 1888 :366-369. -. Halsted, B. D. 1892. Plum Pockets. Bull. N. J. Exp. Stat. 86 :18. FUNGICIDES. Spraying is now looked upon by progressive and sue'Cessful fruit growers as a necessary operation to be per. 134formed if a full crop of' friit of ao good quality In the case of a large and increasig number of diseasesspraying has been demonstrated ona' large scale to be' value. The ga'in' fron' intelligent-spraying depends solely upon the number of trees and the di'. eases prevalent in your orchards. S2praying is plant insurance and, likeb/ins ance, shold' ?e attended to before the disease-hasgaineda foothold ie the orchard. All trees should be'sprayed everyyear-whether the diseases nsmjtlly presen2t mtake their' appearance not.. A large number of formulas. have-been proposed by various investigators for special purposes. We give below directions in some detail for preparation of the fungicides now must widely employed in connectionwith.diseases mentioned in this Bulletin. "isdesired. of immense financial or- the, BORDETAUX MIXTURE. Bordeaux mixture consists of two essential ingredients; freshly slaked limle and copper sulfat, dissolved in water.. Phe fungicidal action is entirely dependent upon the copper sulfat. The lime is added for the following reasons: (1.) To prevent injury to the foliage. (2.) To render the mixture more adhesive. (3.) To render the mixture more readily seen after be,ing applied. STANDARD W %e FORMULA FOR "1.-10" BORDEAUX. give here the mixture so-called Quick Water in formula of thef common "I-1 0" Bordeau~x: because it contains' 1 pound' of" coppe sulfat to 10 gallons of water; Copper sulfat- 5 pounds.. lime (not slaked) A. gallons. Dissolve the J pounds of copper sulfait water a wooden vessel.. I )ilt~e- 50 3 1-2 to +pounds. the, solutions thus. se}- ini hot or cold' cured to 25 gallons.. Slake the lime carefully and thoroughly. Dilute this milk of lime to 25 gallons. ;C. Pour the two -solutions thu-ts obtained through strainers, The mixture in at the same timne, ito thespray the spray barrel should he stirred while the two solutions rare being poured together. ID. Never attempt to mix the two solutions until they have 'been diluted as suggested-above. barrel. SrECIAL A. T1. DT 'cTroNs. C. D. 112. The copper sulfat may best be dissolved in cold'water by suspending it in a ecarse sack near the top of the water. In slaking the lime addat first a small amount of water, )referably hot water, and then, as slaking begins, tinue to add amounts of cold water as needed. add much at ailZne and never allow the lime to become dry, For the more tender foliage of peaches and plums employ the "1-25" Bordeaux mixture, i. e., one containing 2 lpounds of copper sulfat to 50 gallons of water. In all cases use at least 2 pnunds of lime to pounds of copper sulfat. A small amount of yellow prussiate of potash potassinum ferrocranrid dissolved _ii about ,ten times its. bulk of water is often used as the so-called "ferrocvJ anid" test to determine whether or no the Bordeaux, is properlv made. few drops of this solution are added to the Bordeaux. If brown discoloration at once am~ pears not enough lime has been used. Continue to add Never small con- -Nwater or A a lime solution and stir until no discoloration aplpears F' upon adding a few drops of the ferrocyanid solution. The )flost import cuil preeaution to wnlite the cold dlilulte solutions li/me anrd copper, snifat quickly. and of is then to stir the 4b,1_taN'c thoroayhl I le IX.) y. (ice ig. 22 on, 136 AMMONIACAL SOLUTION OF COPPER CARBONAT. This mixture, designed for use when the Bordeaux might by adhering to to fruit injure its market value, is made ac the cording to the following formula: Copper Carbonat-6 ounces. Ammonia-3 pints. Water 50 gallons. The copper carbonat is to be dissolved in the ammonia,, just as much ammonia being used as is required to dissolve the copper carbonat. This solution is then thoroughly stirred into the water. LIME-SULFUR-SALT WASH. This wash, long used along the Pacific coast to control the San Jose Scale, has recently sprung into favor for the same purpose in the East. We mention it here since its use seems to reduce various plant diseases, particularly apple scab and peach leaf curl. It is in a sense therefore both an insesticide and a fungicide. We give but one of the several formulas suggested: Stone or lump lime-15 lbs. "Flowers of sulfur"-15 lbs. Salt 15 lbs. Water 50 gallons. "Place the lime in a kettle, or in a vat if steam is used, and slake it with hot water so that it forms an even white paste. Now add enough water to reduce the lime paste to a thin whitewash. The sulphur and salt are then added and should be thoroughly stirred in. If the mixture is not already boiling, bring it to this point and allow it to boil for one hour." Stir the mixture frequently and at the end of the hour di lute the resulting mixture with hot water to make the re quired amount. Apply the wash, while hot, with any good nozzle to the trees. This mixture is very caustic and must be applied to none. 137 but dormant trees and should' not be allowed to come into, contact with the hands or face. SPRAYING MACHINERY. The type of spraying outfit to be employed and its size depends upon the size of the orchard in which it is to be employed. We can only briefly consider the matter here and refer to the two essential parts of any spray outfit: (1) the nozzle and (2) the pump and its accessory parts. No nozzle of the multitude of forms upon the market is superior td those constructed on the principle of the Vermorel nozzle. These nozzles will give fairly good results even when the pump gives a very low pressure, though best results are secured with pressures of 100 pounds or higher. The "mistry" nozzle (Fig. 24 on Plate IX) made by the Goulds Mfg. Co., is of the Vermorel type and throws a finer spray with low pressures than do the Vermorel nozzles. A good spray pump should have all working parts exposed to the spraying mixtures made of brass or some sort of bronze. And in addition neither rubber nor leather valves should be used. Assuming these two characteristics to be present the spray outfit is to be selected to fit the local conditions, particularly the number of trees to be sprayed. Fig. 23 on Plate IX, shows a well known type of pump to, be attached to a barrel. For further information on the subject of spraying outfits, consult the references in the Bibliography following and the catalogues to be secured from the following firms, -well known as makers of spray outfits: Deming Co., Salem, Ohio. Field Force Pump Co., Elmira, N. Y. Goulds Mfg. Co., Seneca Falls, N. Y. I3 IBLIOGrAPII JY. -Anon. 1904. Spray Calendar. Bull. N. Y. Cornell-Exp.,Stat. 217:123-133. ,.A1iwood, W. B. 1903*. Orchard Studies-XIV. The Lime-Sulphur Wash. Bull. Va. Exp. Stat. 141:213-246. fig. 38-54. Beach, S. A., and Bailey ,L. H. 1900. Spraying in Blooni. Bull. N. Y. Geneva-Exp. Stat. 196 :399-460. pl. 1-3. fig. 1-6. Beach, S. A., Clark, V. A., and Taylor, 0. M. 1903. Spraying Mixtures and Spray Machinery. Bull. N. Y. Geneva Exp. Stat. 243:315-373. pl. 9-15. Booth, N .0. 1900. A Test of Spray Nozzles. Bull. Mo. Exp. Stat. 50:87-115. fig. 1-1-0. Corbett, L. C. 1896. Why, When, What and How to Spray. Bull W. Va. Exp. Stat. 43:227-244. fig. 1-6. °Cordley, A. B. 1903. insecticides and IFugicides. Brief directions for their preparation and use, including spray Stat. 75.27.-43. Fairchild, D. G. 1894. Bordeaux Mixture as a Fungicide. Veg. Path. Bull. Div., (Galloway, B. 1896. Spraying for fruit diseases. T. U. S. Dept. Agr. 6 :1-00. Farmers' Bull. 1-196. 38: fig. 1-6. Gossard, H. A., and flume, H. H. 1904. Insecticides Fungicides. and Stat. 76 :200 243. pl. 1-8. Bull. Fla. Exp. :.This Bulletin bears on title page the date, October, wy thin contains statement, "Issued Noxetnbz-r 30, 1903." 1902, but 139 Green, W. J., and Selby, A. D. 1904. Calendar for treatment plant diseases and insect pests. Bull. Ohio Exp. Stat. Lodeman, E. G. 1896. The Spraying of Plants. pp. xvii, 399. 92 figures. Mac~illan Co., N. Y. City. Parrott, P. J., Beach, S. A.,-and Woodworth, I. 0. 1904. The lime-sulphur-soda wash for orchard Treatment. Bull. N. Y. Geneva Exp. Stat. of 147:41-53. & 247: 59-81. pl. 1-4.' Johnson, T. C. 1904t. Mixtures and Appliances for Spraying. Bull. W. Va. Exp. Stat. 93:67-'118. pl. 1-12. pl. Lowe, V. H., and Parrott, P. J. 1902. San Jose Scale Investigations IV. Bull. N. Y. Geneva Exp. Stat. 228 :389-456. 1-7. Penny, C. IL. The Preparation of Aininonical per Carbonate. fig. Bull. Solution of Cop. Del. Exp. Stat. 22:1-16. 1-2. Orton, W. A. 1896. Smith, J. 1892. 'Stone, G. 1904. Methods of preparing Bordeaux mixture. 'Rept. Exp. Stat. 9-1895 :88-92.p1. 4, fig. 13. B., and Halsted, B. D. Spraying for Insect and Fungous Pests of the Orchard and Vineyard. Bull. N. J.i Stat. 86:1-2.. E., Fernald, H. T., and Waugh, P. A. Fungicides, Insecticides, and Spraying Calendar. Vt. Bull. Mass. Exp. Stat. 96 :1-16. 1 fig. Stubeubranch, A. V. 1902. trgis, 1898. Important Details of Spraying. Bull. Ill. Exp. Stat. A. 68 :157188. p1 . 1-9. fig. 1-3. C. Preparation and application of fungicides. Bull. Conn. State Exp.- Stat. 125 :1-16. 10 figures. 140 Swingle, W. T. ix. An improved method of making Bordeaux ture. Journ. Mycol. 7 :365371. Its chemistry, physical 1.896. Bordeaux properties, and toxic effects on fungi and vlgae. Bull. l)iv. Veg. Phys. and Path. U. S. Dept. Agr. 9:1-37. Tillinghast, J. A., and Adams, 0. E. 1899. Suggestions as to spraying. Bull. R. Is. Exp, Stat. 52 :1-48. 1 fig. Troop, J. 1898. Fornulas for making insecticides and fungb cides, and directions for spraying.,Bnll..nd, Exp. Stat. 69 :35-40. Undernwood, L. M., and Earle, F. S. 1896. Treatment of some fungous diseases. Bull, Ala. Exp. Stat. 69 :243-272. 1894. Mixture: EXPLANATION OF PLATES., PLATE I[. Fig. 1. Bitter r~ot of apples showing both isolated and -con- fluent diseased areas and the concentric circles formed by the 'fruiting bodies' of the fungus 'causing the disease. dustry, IT. (From Bull. 44, Bureau of Plant InS. Dept. Agr.) Fig, 2. Limb cankers produced by the funigus causing the~ bitter rot. (From Bull. 44, Bureau of Plant In dustry,_ U. S. D)ept. Agr.) PLATE II. Fig. 3, Twig of the red cedar showing one of the galls called "cedar-apples." This gall is produced one stage of the same fungus that causes the rustof apple leaves. (Original. ) by 141 The lower surface of an apple leaf showing the peculiar elongated horn-like fruiting bodies of the fungus causing the apple leaf rust. (FrontRept.. U. S. Dept. Agr. for 1888.) Fig. 5. Fly speck, and sooty blotch of the apple. (From, Bull. 79, Ohio Exp. Stat.) Fig. 6. The upper pile of apples is'from the sprayed tree, the lower pile from the unsprayed tree both together show the advantage in spraying against Exp. Stat.) apple black rot. (From Bull. 59, Fig. 4. Ky. the PLATE III. Fig. 7. Brown rot of peaches. (From Bull. 50, Ga. Exp. Stat.) Fig. 8. "Mummy" peaches, killed by the brown rot diseases,, -adhering to the tree and thus constituting a very fruitful source of new infection.'(From Bull. 50,, Ga. Exp. Stat.) PLATE IV. Fig. 9. Leaf curl of peach. (From Bull. 20, Div. Veg.. Phys. & Path. U. S. j)ept. Agr.) Fig. 10. Rosette of peach. (From Journ. Mycol. Vol. 6.) PLATE V. Fig. 11. Longitudinal section of a root affected with crown. gall. (From Bull. 33, Arizona Exp. Stat.) Fig. 12.. Crown gall ; the upper left hand figure shows gall, on Lombardy poplar,, the upper right hand figure on pear and the two lower figures on peach. (Fromt Journ. MNycol. Vol. Crown gall on apple ; this gall appeared :1t the, F'ig. point where the graft was inserted shown at "' Exp. Stat.) in the figure._ (From Bull. 93; Fig. 14.' Crown, gall showing the growth of new gall tissue 13. 7.) Ky. after the removal of the old gall. Arizona Exp. Stat.) (From. Bull. 33, 14.2 PLATE VI. Pig. 15. -Fi g. 16. blight. (Original.) root of peach. (From Rept. Exp. Stat. for 1900.) Pear Hairy Geneva N. Y. "Fig. PLATE VII. 17. Plum pockets. (From Rept. U. S. Dept. Agr.1888.) -Fig. 18. Black knot on plum. (From Prof. Farlow's paper in Bull.'-Bussey Institution, Fig. 19. Apple canker. (From Bull. 163, N. Y. Geneva Exp. Stat.) 1876.) PLATE VIII. PLig. 20. "Shot-hole" affect produced on Japan plumlleaves by improper spraying. (From Bull. 164,N.. Cornell Exp. Stat.) 'Fig. 21. Cherry leaf-spot disease. (From Report N. Y. Geneva Exp.. Stat., 1896.) PLATE IX., Fig. 22. Jars showing, after one hour's standing, the amount of settling of the precipitate in Bordeaux mixture mnade in tbe following ways. The lower light cob ,ored part in each figure is the A. Dilute limle poured into dilute sulfat slowly. B. Dilute sulfat poured into dilute limle slowly. C. Made as in E, but uising hot lime milk. D. Made as in E, but less thoroughly stirred. E. Properly made from dilute solutions, quickly united thoroughly stirred. F. -Made as in E, but with concentrated solutions. precipitate: and G. II. Properly made mixture, one day old. Old B~ordeaux mixture, two weeks old. I. "Bordeaux Powder" mixed with water. Fi. 23. One example of the barrel-type of' spraying apparatus. (Fromt Bull. 243, N. V. Geneva Exp. Fig. 24. "M istry" spray nozzle. (Cut loaned by the Goulds Mfg. Co., Seneca Falls, N. Y.) Stat.) Fig 1, I., l ' : i t~ pt/v Fig. 4. 14 Fig 3. Fig vi 'I N / ~ 7t Pr I Fig. 7. 4 PL I' Figi. 9. AL - . p. f, Y .. ' III \ 'I': I t. E Fig 11. Fig 12. f,~ IF r g. . 11 I 'll \ I .\ / Fig. 18. Fig. 17. PLr. II Fig.'2C. I'l\ II1. ix Fiy 2 ' a Fig. 24. Fig. 23.