76 



DuTT (H. L.). The Methods of Control of Agrotis ypsilon in Bihar. — 

 Rept. Proc. 3ni Enloin. Mcetinii, Piisa, February 1919, Calcutta, 

 u, 1920, pp. 622-625. 



In view of the habits of Agrotis ypsilon, the ploughing of the land 

 four or five times before sowing should largely reduce the number of 

 caterpillars. In the chaur land of India, however, this method of 

 cultivation is impossible, the soil being composed of stiff, heavy clay 

 on which cultivation is only practicable for 15 to 20 days after the flood 

 water luis left the land. A common method of cultivation in the lower 

 chain- land is broadcasting, i.e., scattering the seed on the land 

 immediately after the water has left it. The crop on an area so treated 

 is always better than that on a ploughed area, probably because the 

 surface of the ground is smoother and affords less shelter to the cater- 

 pillars. Broadcasted areas do not, however, produce as large a crop 

 as ploughed areas, and therefore the method cannot be generally 

 adopted. Rotation of crops is also useless as a remedy, since all crops 

 grown on chaur land are attacked by these cutworms. Poison-baits 

 are impracticable owing to the enormous extent of the area. Experience 

 during the last eight years has shown that the most satisfactory 

 method of control is the use of Andres-Maire traps R.A.E., A,\, 507 ; 

 iii, 320 ; v, 365] against the adults, supplemented by handpicking 

 the larvae of the first generation on higher land. The results obtained 

 by the use of these traps since 1911 are recorded. The destruction of 

 weeds does not reduce the numbers, as the caterpillars migrate to other 

 food-plants, such as tobacco. 



With a view to studying the possibility of control by natural parasites, 

 the life-history of a Braconid has been worked out. The period from 

 oviposition to adult lasts 36 days in January and February, and 25 days 

 in March. In April the egg and larval stages occupy 12 days only. 

 The larva aestivates in March or April ; it is not yet known when it 

 emerges as an adult, but this presumably occurs when the caterpillars 

 of the first generation are appearing in September or October. At that 

 time the percentage of parasitism is very low. A large number of 

 parasites, of which there are several, including Braconids and Tachinids, 

 were therefore reared in the insectary in February and March 1917 

 and 1918 and allowed to go into aestivation in April. In both instances 

 they failed to emerge or even to pupate. It is evident that the 

 natural factors controUing their emergence from the aestivating pupae 

 did not prevail in the insectary. Attempts will be made to determine 

 what these factors are, and to find out whether the caterpillars 

 found in the hills during the rains are parasitised there, and if so, 

 whether the parasites concerned could be bred out for use in the 

 chaur lands. 



FuLLAWAv (D. T.). Control of the Melon-fly in Hawaii by a Parasite 



introduced from India. -Rept. Proc. ord Eiituiu. Meeting, Piisa, 

 February 1919, Calcutta, ii, 1920, pp. 625-629. 



An account is given of the author's journey in southern India and 

 elsewhere in search of parasites of the melon fly, Dacus [Chaetodacus) 

 cucurbitae [R.A.E., A, v, 2, etc.]. At the present time, the Indian 

 parasite, Opiusfletcheri, destroys 50 per cent, of the melon-flies infesting 

 fruit in Hawaii. 



