INSTITUTE AND COLLEGE, PUSA, FOR 1911-12 61 



in Bihar, particularly where " moorhun " plant was kept 

 for seed bearing. As there is much confusion between the 

 condition due to the insect pest Psylla and that known as 

 " wilt," a conjoined mycological and entomological investi- 

 gation was undertaken. I visited the Research Station of 

 the Bihar Planters' Association in November and examined 

 the crop which had been kept for seed and which was at 

 this date almost entirely destroyed. No sufficient explana- 

 tion of the death of the plants could be found and it appears 

 unlikely that it is due to a definite fungus parasite. As, 

 on the other hand, it appears to be quite clear that Psylla 

 does not kill the plant in this fashion, it is evident that 

 further investigation is necessary. The preliminary stages 

 of this were commenced last year. 



{i) Forest tree diseases. — A large number of specimens 

 of diseases of forest trees were received from the Forest 

 Department. These included various pines, deodar, 

 shisham, teak, ^'nahor," Casuarina, "sal," "mahua," Cassia 

 fistula, mulberry, etc. In several cases the diseases were due 

 to parasites already known and suggestions for treatment 

 could be given. In others, notably the nahor disease in 

 the Sibsagar and Teesta Divisions, the cause is a fungus 

 which it has not yet been possible to identify and no 

 recommendations can be made. 



{j) Other flant diseases. — I visited Lyallpur in October 

 to investigate the cause of the death of cotton plants in 

 certain areas of the Government Farm. No parasite was 

 found but evidence was obtained to show that the damage 

 was due to root injury, resulting from the presence of an 

 impermeable stratum some distance below the surface of 

 the soil. A large number of specimens of cotton plants from 

 fourteen villages in the wilt-infected area in Berar were 

 sent for examination by Mr. Clouston. The percentage 

 of wilt varied from over fifty to three. Buri cotton, so far, 

 remains immune and Mr. Clouston is now working out how 

 far this advantage compensates for its lower yield as com- 

 pared with the varieties commonly grown. Mr. Shaw has 

 investigated the disease of Sisal caused by Colletotrichum 



