INSTITUTE AND COLLEGE, PUSA, FOR 1911-12. 69 



6. Research. — The investigation of the habits and biology 

 of insect-pests has been continued and among those studied 

 may be mentioned the " Bherwa," the Fish Insect, White 

 Weevil, Mango Leaf Hopper, Surface Grasshopper, Para- 

 sites of Cotton Bollworms, Cane Borer, Cane Fly, Wheat 

 Stem Borer, Termites, Grain and Flour Beetles. The ex- 

 periments on the preservation of wood and other materials 

 from the attacks of Termites (white-ants) are still in pro- 

 gress and the efficacy of various preparations and the 

 relative immunity of different kinds of woods are being 

 tested. At the request of the Bihar Planters' Association, 

 an investigation into the '' Psylla " disease of indigo was 

 commenced and is being continued. 



7. Insecticides. — A number of preparations sent in for 

 trial were tested and reported on. The first edition of 

 Bulletin No. 23 on insecticides speedily ran out of print and 

 a second edition revised and with some additions has been 

 published. As many inquiries have been received as to 

 where various insecticides and spraying machines were 

 obtainable lists of the firms supplying these have been pre- 

 pared and circulated. 



8. Sericulture. — The experiments with crossing multi- 

 and univoltine races of Mulberry Silkworms to procure a 

 superior silk-producing multivoltine race have been conti- 

 nued but though many crosses were made, it has up to the 

 present been impossible to produce a stable multivoltine 

 race, although as mentioned last year some imj^rovement has 

 been obtained in the quality of the silk. 



Univoltine European races were successfully reared on 

 pruned tree mulberry, wild mulberry and bush mulberry and 

 arrangements have been made to distribute eggs of these 

 univoltine races for rearing in October. The difficulty with 

 these eggs is that the temperature of the plains is too high 

 to preserve them successfully during the dormant period 

 and arrangements have been made to send the eggs to places 

 in the hills where the temperature is not so extreme. 



The Eri Silkworms were reared successfully throughout 

 the year except in May and June, when, owing to the 



