1917] DISEASES OF PLANTS. 841 



A nematode disease of the dasheen and its control by hot-water treatment, 

 L. P. Byars {Abs. in Phytopathology, 7 {1911), No. 1, p. 66).— The dasheen 

 {Colocasia esculenta) is reported as having been found attacked by a nematode 

 (Heterodera radicicola). The disease, it is claimed, can be successfully con- 

 trolled by planting on uninfected land selected cormels from disease-free areas 

 or diseased cormels which have been treated with water at 50° C. (122° F.) 

 for 40 minutes. 



A bacterial stem and leaf disease of lettuce, Nellie A. Beown (Abs. in 

 Pfiylopafhology, 7 (1917), No. 1, p. 03). — xV wilt disease of lettuce is briefly 

 reported, the disease having been observed in Beaufort County, S. C, in 1910. 

 The affcctetl plants were wilted and rotting was often rapid. Bacteria were 

 abuudtint. and the organism isolated, when inoculated into lettuce, produced 

 the blue-green color throughout the vascular system and pith which charac- 

 terizes the normal appearance of the disease. The organism in its morphological 

 and cultural characters is said not to correspond to any recorded as pathogenic 

 to lettuce. 



Studies upon the anthracnose of the onion, J. C. Walker (Abs. in Phyto- 

 pathology, 7 (1917), No. 1, p. 59). — It is claimed that a morphological study of 

 the organism CoUetotrichnrn circinans confirms the findings of Voglino that the 

 fungus belongs to the genus Colletotrichum and not Vermicularia. Inoculation 

 of the fungus from onion into apple fruits is said to have resulted in a rot very 

 similar to the Volutella rot, but further study is necessary before the two fungi 

 can be considered identical. 



The fungus is said to winter over in the soil and consequently the disease is 

 most severe on old onion fields. Spraying the bulbs before harvest or in the 

 crates after harvest has not proved beneficial. Yellow and red varieties of 

 onion are claimed to be highly resistant, and this fact is believed to offer 

 encouragement for the development of a resistant white strain. 



Pink root, a new root disease of onions in Texas, J. J. Taubenhaus and 

 A. D. Johnson (Abs. in Phytopathology, 7 (1917), No. 1, p. 59). —A new disease 

 of onions locally known as pink root is said to occur in Webb County, Tex., 

 but only where onions are grown for two or more years on the same land. 

 The roots of the affected sets in the seed bed or of the plants in the field turn 

 pink in color, shrivel, and die. As fast as new roots are formed they become 

 infected and the normal development of the bulbs is affected. The undersized 

 bulbs resulting are worthless so far as market is concerned. 



The cause of the disease has not yet been determined. 



Black spot of pepper, L. E. Melchers and E. E. Dale (Abs. in Phytopa- 

 thology, 7 (1917), No. 1, p. 63). — A disease of peppers is described with which a 

 species of Alteruaria has been constantly associated. Inoculation experiments 

 have shown that the organism is only weakly pathogenic to normal tissue and 

 that it becomes established laa-gely through injuries to peppers in the field, the 

 principal means being sun scald and frost injury. 



Notes on curly dwarf symptoms on Irish potatoes, W. L. Dukrell (Abs. in 

 Phytopathology, 7 (1917), No. 1, p. 71). — Curly dwarf symptoms are said to have 

 been very prevalent in Iowa during 1916, particularly on the varieties Irish 

 €obbler, Rural New Yorker, and Early Ohio. The disease made its :ipi>earance 

 on the early plantings about June 10 and developed throughout the season. In 

 August, plants that had been normal up to that time showed typical signs of 

 curly dwarf on the foliage, and the upper third of the plants had shortened 

 internodes and crinkled and curled leaves, giving the plants a bushy appear- 

 ance. These symptoms are said to have been induced in the field by the hot, 

 dry weather in August, and similar ones were later artificially developed in the 



