DISEASES OF PLANTS. 841 



Europe. It attacks plaats in many families, l)ut mainly dicotyledons. Large 

 sclerotia are observable in connection with crocus and alfalfa. The existence 

 of distinct forms or races of this species requires further Investigation. The 

 organism has not yet proved to be culturable by the usual laboratory methods, 

 and the evidence collected is still insufficient to identify the perfect form. 



R. solani, which is readily distinguishable from the above, is said to be 

 widely distributed in America and elsewhere on potato. The other host plants 

 represent many families, Asparof/us sprcngcri being the only monocotyledonous 

 host yet reported. The types of disease caused by this species are very diverse, 

 damping off and root and stem rots being the most important direct effects. 

 The organism is readily culturable by the usual laboratory methods. The per- 

 fect stage is thought to be C. vagum. 



Contrasted descriptions are given of these two fungi, with notes on other 

 species, some of which are considered as having insufficient affinities to be 

 included in the genus Rhizoctouia. 



A bibliography is appended. 



Notes on plant parasitic nematodes, L. P. Byars (Abs. in Science, n. ser., 

 43 (1916), JVo. 1102, p. 219). — Attention is called to the general characteristics of 

 nematodes and to the economic importance and present distribution of the bulb 

 and stem infesting nematode, Tylcnchus dipsaci; T. tritici, a parasite of wheat 

 kernels ; Apheleywkus armcrodis, a violet bud organism ; and Heterodera 

 radicicola, a gall-forming nematode on a number of plants. 



[Plant diseases in Barbados], J. S. Dash (Rpt. Dept. Agr. Barbados, 1913-14, 

 pp. 4^-45). — It is stated that CoUetotrichuni falcatum, the cause of sugar cane 

 red rot, was rarely met with during 1913-14, but Marasmius sacchari, the 

 cause of a root disease of cane, appeared as usual. Thielaviopsis ethaccticus, 

 which attacks cane cuttings principally, was severe in several places. It can 

 be controlled, it is said, by passing the cuttings through Bordeaux mixture 

 just before planting. 



A banana disease may be connected with the presence of a Fusarium and a 

 Gloeosiwrium on the diseased portions. Insufficient nutrition and inferior liv- 

 ing conditions generally may render the trees susceptible to these fungi. 



Specimens of dieased tomato showed two diseases, one a leaf mold {Clado- 

 sporinm fnlrum), the other a fruit anthracnose due to a Gloeosporium. 



Grape mildew (Oidium tnckcri, Uncimila spiralis) was successfully treated 

 with flowers of sulphur and lime in the form of a powder. 



A dieback of cassava, ascribed to a Gloeosporium (possibly G. manihot), 

 may be controlled, it is thought, by care in tlie selection of cuttings and soak- 

 ing them in Bordeaux mixture just before planting. 



Entypa erumpcns is said to have caused a loss of Ficus nitida. 



Cultivated snapdragon (Antirrhimim sp.) showed evidences of a disease of 

 the roots and of the stem near the ground, from the fructifications of which 

 a CoUetotrichuni could be developed. This is said to be somewhat different 

 from C. antirrhini described by Stewart (E. S. R., 12, p. 1055) as causing 

 anthracnose of snapdragon. L'^se of seed for propagation is advised. 



[Plant pests and diseases in Grenada], .1. C. Moore (Imp. Dept. Agr. West 

 Indies, Kpt. Agr. Dept. Grenada, 1914-15, pp. 7, 8, 19). — A report of Ballou and 

 Nowell, besides giving information regarding animal pests, records the dis- 

 covery of root diseases due to three species of Rosellinia. Two of these were 

 found attacking cacao, one in wet, the other in drier situations. The third 

 form, R. bunodes, was observed on hibiscus in the interior of the island. 



In another part of the report, brief notes are given on thread blight of cacao 

 and nutmegs, also canker, pod brown rot, and dieback of cacao. 



