1917] DISEASES OF PLANTS. 449 



Field experiments with tokra of tobacco have already yielded some results. 

 Orobdnche cei-nua and O. indica occur on tobacco, the latter being much more 

 serious to solanaceous crops and the formei' causing more damage to crucifers. 

 The effects of chemical manures on the influence of tokra are being tested. 



Black thread of Hevea in Lower Burma, characterized externally by black 

 lines in the tissue above the tapping cut and by failure of the tree to regenerate 

 the bark over the tapped area, has not yet proved to be due to a fungus parasite 

 but hyphae of a Phytophthora have been found in adjacent bark. 



A disease of sal (Shorea robusta) in the forests of the Duars vsras associated 

 in every dead or dying tree with the presence of a rhizomorphic root fungus 

 showing sporophores in advanced cases, and all showed a diseased condition 

 of the phlojm. The disease may prove to be due to a Fomes, the conditions for 

 attack by which are not yet known. 



Rhizoctonia napi was found to be a serious parasite of mustard and gram, 

 though limited by its inability to grow actively at temperatures above 29° C. 

 (80.3° F.). A fertile stage discovered is said to be identical with Botrytis 

 cinerea. R. destruens causes a serious disease of betel vine and potato in 

 Bengal, and it also occurs on suran, alfalfa, and peanut. This fungus may have 

 a perfect stage in the genus CJorticium. Experiments suggest that corrosive 

 sublimate is more reliable as against Rhizoctonia than is either formalin or 

 copper sulphate. Studies regarding the causation of blight of opium poppy ren- 

 der it probable that Rhi5»ctonia is seriously parasitic on this plant only under 

 bad conditions, such as poor soil or defective drainage. Peronotpora arborescens 

 was abundant on poppy near Ghazpur. 



Anthracnose of betel vine was investigated with slight results. Anthracnose of 

 chillies caused much trouble in Burma. 



Preliminary study of the soil floras of India showed a striking similarity 

 of these with those of Europe. The red rot sugar cane fungus attacked juar 

 under laboratory conditions. A banana rot was caused by a Fusarium, this 

 disease appearing to be distinct from the Panama disease of bananas. The 

 potato blight fungus is not able to survive in the heat of the plains. Results 

 are to be published soon of a study of Phytophthora in Vinca. A disease of 

 chillies proved to be of the type known as wilt. In Bihar the treatment of oat 

 smut with formalin was, as usual, completely successful. 



An account of plant disease work by departments is given in brief form, 

 and this is followed by a short list of publications during 1914-15. 



Nonparasitic stem lesions on seedlings, C. Hartley (Abs. in Phytopathology, 

 6 (1916), No. S, pp. SOS, S09). — Attention is called to a disease affecting the 

 bases of the stems of young seedlings of conifers and various herbaceous plants, 

 for which the name white spot is proposed. In many ways this disease resem- 

 bles damping-off and is frequently confused with it, but It is considered that 

 the disease is caused by high temperature at the soli surface, probably combined 

 with the effects of light. 



Life history and poisonous properties of Claviceps paspali, H. B. Beown 

 (V. S. Dept. Ayr., Jour. Ayr. Research, 7 (1916), No. 9, pp. J^Ol-^OG, pi. 1, figs. 

 2).— In continuation of previous work (E. S. R., 34, p. 676), the author gives 

 the results of an investigation carried on at the Mississippi Experiment Station 

 on the life history and poisonous properties of this ergot. 



The fungus has been found quite abundantly In the vicinity of this station, 

 at least 90 per cent of old heads of Paspalum dilatatum showing Infection. 

 Inoculation experiments have demonstrated the possibility of producing the 

 disease. It has been observed that th© sderotta are readily found on the 

 ground during the winter, where they remain until spring. In addition to the 



