No. 1, November, 1921] PATHOLOGY 37 



and branches of the cultivated apple {Malus sylvestris) and commonly known as blister 

 canker. The disease produced appears in several different forms called staghead, yellow 

 streak, sunscald, the enclosed form, and the common form. Cankers resulting from artificial 

 inoculation enlarge most rapidly at the beginning of growth in the spring. When the wood 

 is parasitized without the formation of cankers the presence of the fungus may be detected 

 by the appearance of black streaks in the wood. The fungus is disseminated chiefly by means 

 of the ascospores, which are discharged normally in August. Usually, 2 years are required 

 for the maturity of the ascospores. The virulence of the disease and the success of attempts 

 to control it are largely dependent upon environmental and other conditions, such as location, 

 soil, rainfall, pruning, spra3ang, variety, overbearing, and age of host. Shellac followed by 

 coal tar was found to be the most satisfactory dressing for the wounds made in pruning out 

 diseased branches. — F. C. Stewart. 



215. HiLEY, W. E. The larch needle-cast fungus, Meria laricis Vuill. Quart. Jour. 

 Forest. 15: 57-62. 2 fig. 1921. — This fungus appears to be exceedingly common in Britain. 

 It causes young larch needles to turn brown and fall during the summer months. This type 

 of leaf-cast has commonly been attributed to frost, but can easily be distinguished from frost 

 injury. The youngest needles are not affected, only those a few inches from the shoot apices, 

 and the disease spreads gradually up the shoots. The needle is not killed outright as when 

 frosted; instead the apex first becomes brown and this discoloration then spreads gradually 

 to the base. The bulk of the needles on the dwarf shoots are unaffected. The disease is most 

 prevalent in wet weather, and most destructive in the nursery. Young plantations are often 

 attacked and trees as much as 30 feet high have become very brown in August. As stems are 

 unaffected by the disease, trees are seldom if ever killed. The European and western Ameri- 

 can larches are subject to attack, but the Japanese larch seems immune. Fruiting bodies 

 of the fungus are formed only in a humid atmosphere. They consist of bundles of conidio- 

 phores growing out through the stomata. The hyphae, which compose the bimdle, are color- 

 less and septate. From the apex of each segment conidia are abstricted, which may infect 

 other larch needles. Whether the germ-tubes affect entry through stomata or by piercing the 

 cuticle is unknown. — C. R. Tillotson. 



216. Hunt, T. F. Pythiacystis "brown rot" affecting deciduous trees. Monthly Bull. 

 Dept. Agric. California 10: 143-145. 1921.— The Pythiacystis rot is distinct from that caused 

 by Sclerotinia cinerea. The causal organism lives over in the soil and most of the infection 

 develops on parts of the tree nearest the ground, a small, dark spot on the bark being 

 the first indication. Under favorable weather conditions the disease spreads rapidly 

 over trunk and twig. No definite control measures have been determined. Bordeaux and 

 lime-sulphur sprays together with good drainage are suggested as control measures. — E. L. 

 Overholser. 



217. Jones, L. R., and Mattd Miller Williamson. Bacterial leaf spot of red clover. 

 [Abstract.] Phytopathology 11: 50. 1921. 



218. Melchers, L. E. Rhizopus sp. associated with a decay of unripe strawberries in the 

 field. [Abstract.] Phytopathology 11: 44. 1921. 



219. Morris, H. E., and D. B. Swingle. An important new disease of the cultivated 

 sunfiower [Sclerotinia libertiana]. [Abstract.] Phytopathology 11: 50. 1921. 



220. PovAH, Alfred H. W. Valsa poplar canker. [Abstract.] Phytopathology 11: 45. 

 1921. 



221. Rap, C.W. Bacterial blight of beans. Oklahoma Agric. Exp. Sta. Bull. 131. 40 p., 

 17 fig. 1920. — The history of the disease, its distribution, and importance are reviewed. The 

 methods of infection and distribution of the organism are outlined. It is reported to live over 

 winter on the seed, straw, and in the soil, and to be disseminated by rain, dew, insects, and 



