434 SUMMARY OF CURRENT RESEARCHES RELATING TO 



its spores on the under side of the leaf, and spreads quickly. Early and 

 repeated spraying with Bordeaux mixture is recommended. 



Donald Reddick * describes the development of the black-rot disease 

 of grapes due to the fungus Guignardki Bidwellii. It attacks every 

 part of the plant. In the early season of the year the ascus fruits 

 develop on mummified berries in the soil. The spores infect the grapes 

 and produce pycnidia, at a later stage sclerotia are formed. Successful 

 artificial cultures of the fungus were made. 



Keith Bancroft! has described a disease of Para rubber trees preva- 

 lent in the Malay States. It is caused by a wound parasite, Thyrdaria 

 tarda, and usually follows some other attack. The infected shoot dies 

 off ; the fungus may then travel to other parts of the tree, and may 

 eventually cause its death. Methods of treatment are recommended. 

 A note is added on various leaf fungi met with in the East. 



A disease called Black-leg of Cabbage has been ascribed by J. F, 

 Manus % to the attack of Phoma oleracea. It is widely spread over the 

 world and does great damage. It originates in the seed beds and should 

 be combated there by soil treatment. 



Florence Hedges § found that knots and witches' brooms on Citrus 

 trees were caused by the fungus Sphaeropsis tumefaciens sp. n. The 

 knots vary from the size of a pea to 2 or 3 in. in diameter. In time 

 these " galls " kill the tree. 



C. L. Shear II has proved that the fungus Fnsicoccum viUcolum, 

 causing " dead-arm " or necrosis of tlie vine, is the pycnidial stage of 

 Gryptosporella viticoJa sp. u. 



Diseased Scluzmithus plants have been examined by C. N. Jensen 

 and V. B. Stewart.1" Stems, branches and leaves are affected by canker- 

 like spots or lesions. The cause of the disease is a minute fungua, 

 CoUetotrichum Schlzanthl sp. n. 



Bruce Fink ** describes the injury done to Piiius Strodus by the 

 fungus Genangium Abietis. The twigs were attacked, then the larger 

 branches ; some trees were entirely destroyed. The fungus is rare in 

 America, but is reported from Germany as injuring pine-trees. 



M. T. Cook and J. J. Taubenhausft describe a rot of sweet potato 

 caused by Trlchoderma Konlngl. T. ligaorum was also present, but of 

 less importance. The fungus causes circular light brown spots. The 

 flesh of the attacked potato is hard and water soaked, with a black zone 

 at point of contact between healthy and diseased tissue. When decay 

 is well advanced a white mycelial growth is formed on the surface bear- 

 ing the spores of TricJwderma. 



H. T. GiissowJI records the occurrence of silver-leaf disease in 

 Nova Scotia. He reviews the work done on this disease. 



* Cornell Univ. Agric. Exper. Stat., Bull. No. 293 (1911) pp. 299-364 (5 pis.). 

 See also Ann. MvcoL, x. (1912) pp. 101-2. 



t Dept. Agric. Federated Malay States, BiUl. No. 14 (1911) 23 pp. (figs, and 

 diagrams). J Phytopathology, i. (1911) pp. 28-38 (2 pis.). 



§ Phytopathologist, i. (1911) pp. 63-5 (1 pi.). 

 !i Phytopathologist, i (1911) pp. 116-19 (5 figs.). 

 ^ Phytopathologist, i. (1911) pp. 120-5 (1 fig.). 

 ** Phytopathologist, i. (1911) pp. 180-3 (1 pi.), 

 tt Phytopathologist, i. (1911) pp. 184-9 (2 pis.). 

 XX Phytopathologist, i. (19L1) pp. 177-9 (1 pi.). 



