n Diss;Asts. and cherries are often attacked 1,.? the same fungi. Leaf blight or shot bole is due to the presence of one or both of two 11111,4i. Cyhildremputiettil pall; 1111d i':ept014(1 Cerfl iml. in the leaves. the symptoms being alike on both plum and cherry. Cireular purplish spots one-cighth Mill in diameter appear: later the tissues become broWn and break out from the leaves, leaving holes as though made shot. In severe cases t he leaves torn yellow and the trees are defoliated. This disease can be prevented by spraying the IVCS With Bordeaux mixture at intervals of two weeks frum the time the leaves appear until July. Another disease to which the plum and cherry are :subject is the black knot or plum knot, due to Pburriglifio morbosa, which appears as a serious pest only upon sour cherries and upon plums. When mature the black knots are rough wart-like excrescences upon the branehes. At first they are yellowish in color, but soon become darker, the surfaces having a velvet-like appear ance. This soon ditin ppearti and the knots grow still darker. in winter becoming black. The fun gus is spread by its spores, which, lighting upon a branch in a crevice in the bark, soon infest the limb. It also remains alive during winter, the mycelium remaining in the Ivuigs and branches. The infested branches should be cut and burned, and where knots are on large limbs or upon the tree trunks Ilwy may be cut out or painted with kerosene. After careful pruning the trees may he sprayed during the growing season with any good fungicide (q.v.) to prevent any spores that
may lied lodgment from germinating. A disease peculiar to the pimp is that known as plum pockets, due to attheks of Exuasvus pruni. The fruit is infected soon after blossoming and begins to swell until it beenmes an inch or t WO in length. At first the 'pocket' is light in color. hut finally dark brown ox black. and the fruit falls to the ground. It, is usually hollow and bladdery in appearance, hence the name. The walls of the fruit are thickened, but it contains no St • or pit. The haves and stems are also attacked, the affected parts assuming swollen,dis torte(' shapes. This disease can be controlled to some extent by thorough use of fungicides. Ap plications shinild lie made before the buds have opened and again just after the flowers have fallen.
For an of plum eultore in America and deceriptions of the varieties grown, consult: Waugh, Piums u»d Plain cuff urc ( New York.
1 901 ) Coll. Culture of Notice flaws in the Agrieultural Experiment Station Bulletins 63 and 87) ; Bailey, The Hotted .Wu tire Plums aml Cherries (New York, Cornell Experiment Station Bulletin :38) id.. The Japanese Plains in America (ib.. Bulletins 62. 106. 139, and 175) : Waugh, The Pollination of Plums and Hybrid Plums (Vermont Experi ment Station Bulletins 53. f7, and 75, and refer ences for 1 8 9 6-1 901). See Colored Plate of Duct' P55.