INSTITUTE AND COLLEGE, PUSA, FOR 1913-14. 55 



not yet available, that the Indian disease is decidedly less 

 virulent than that in the United States. India is fortun- 

 ate too in possessing a race of cotton, " buri," which is abso- 

 lutely immune to the disease. Arrangements have been 

 made, through Mr. Clouston, Deputy Director of Agricul- 

 ture, Central Provinces (to whom the discovery of this pro- 

 perty of " buri " cotton is due), to supply seed of this var- 

 iety for trial in the United States in wilt infected tracts, 

 and in return we are to receive American wilt-resisting 

 varieties for trial in India. There is no other known 

 method of lighting Fusarium wilts but by the growth of 

 immune or resistant varieties. 



Sesamum wilt has also been proved to be due to a 

 Fusarium, and cross inoculations have confirmed what was 

 already probable from morphological study, that the cotton 

 and sesamum diseases are distinct and are due to different 

 species of Fusarium. It is, in artificial inoculations, a 

 much more virulent disease than the cotton wilt, proving 

 fatal in every case tried — several hundreds. No resistant 

 variety is known, but the cold weather (rabi) crop is less 

 subject to the disease than the monsoon (kharif) varieties. 

 Further work on these diseases will be resumed when 

 opportunity arises. 



(6) Phytojj/ithora investigations. — The potato blight due 

 to Ph. infestans (Mont.) de Bary, was investigated by Mr. 

 J. F. Dastur, First Assistant. It was discovered that the 

 fungus does not survive in the heat of the plains of India 

 and is not therefore likely to become a serious pest, except 

 possibly in the hills. A species of Phytophothora has also 

 been discovered attacking Vinca and Petunia; it is a var- 

 iety of the Ph. parasitica on castor which has been the sub- 

 ject of a recent memoir. The slight variation in measure- 

 ments and a few differences in the inoculation experiments 

 may be accounted for by the influence of the host plant. 



(7) Anthracnose. — This disease has been investigated 

 upon the betel vine, plantain, chilli and papaya. In the 

 case of the betel vine the perfect stage of the species of 

 C olletotrichum has been discovered to be an Ascomycetes 



