DISEASES OF PLANTS. 451 



In a laboratory experiment on the effect of the different spray materials on 

 the germination of sporldia, all of the fungicides were found to reduce germina- 

 tion materially. 



While spraying was found efficient in controlling apple rust, It is thought 

 that it would be cheaper and more effectual to remove cedar trees from the 

 vicinity of orchards. 



Evaporation of water by normal or by chlorotic leaves of pear, J. 

 Cbochetelle {Jour. Agr. Prat., n. ser., 26 (1013), No. 41, pp. 469, //70).— The 

 author reports an average hourly evaporation per square centimeter from the 

 surface of green and of chlorotic pear leaves of 5.72 and 1.76 mg., respectively. 

 This is considered to show a freer circulation of water in the green leaves. 



On a disease of greeng-age trees caused by Dermatella prunastri, W. J. 

 DowsoN (New Phytol., 12 (191S), No. 6, pp. 201-216, figs. 5).— An investigation 

 was begun on a disease of greengage plum trees which was carried little beyond 

 the identification of the fungus and determining some facts regarding its life 

 history when the work was terminated, but the author presents the results as 

 far as they had been conducted, giving an account of the isolation of the fun- 

 gus, field observations, inoculation experiments, etc. 



It is stated that the greengages were chiefly attacked, but that the fungus has 

 also been found on either varieties. Diseased branches and twigs die back and 

 the dead branches show the presence of the fruiting bodies of the fungus. 

 Inoculation experiments were begun which indicate that infection takes place 

 through wounds. The mycelia arising from both conidia and ascospores were 

 grown on nutrient agar and sterilized pieces of greengage wood, and pycnidia 

 were produced in about three weeks. The mycelium was found present in all 

 the tissues of the host, particularly in the wood and pith. Its advance into a 

 branch is preceded by gumming in the woody elements. Inoculation of healthy 

 trees with the mycelium of D. prunastri is said to have led to infection. 



Silver-leaf disease, F. T. Brooks {Jour. Bd. Agr. [London'], 20 {1913), No. 8, 

 pp. 6S2-690, p?s. 2). — ^A summary account is given of the author's investigations 

 and observations on the silver-leaf disease in continuation of the report pre- 

 viously noted (E. S. R., 29, p. 847). The present article deals principally with 

 the part played by Sierciim purpurcum in causing the disease. 



The anthracnose of the mang-o in Florida, S. M. McMukran {U. S. Dept. 

 Agr. Bui. 52, pp. 15, pis. 4, figs. 4). — The results of a study of the mango 

 anthracnose, due to Golletotrichum glceosporioides, in Florida together with 

 some spraying experiments for its control are given. 



The author states that the production of mangoes is seriously interfered with 

 in certain seasons by this fungus, which attacks not only the flower clusters, 

 fruits, and leaves, but also the young shoots. The blossom blight form of the 

 disease is said to be the most serious, and the amount of damage is dependent 

 on weather conditions, moist, showery weather being ideal for its rapid 

 development. 



So far as the spraying experiments in Florida are concerned, spraying proved 

 of little value in preventing the blighting of the blossoms during rainy seasons 

 at blooming time, though it served to keep the panicles and fruits free from 

 infection. The author believes that seasons will never be so dry but that 

 spraying will have to be resorted to in order to keep fruits free from disease 

 after they have set. 



Court-noue, L. Ravaz {Vie Agr. et Rurale, 2 {1913), No. 27, pp. 10-15).— The 

 author discusses briefly the present distribution of court-noue under its various 

 names, its characters, its alleged causes, its conditions of development (in- 

 cluding susceptible or resistant varieties), and suggested preventive measures, 



