AND COLLEGE, PUSA 3 FOR 1915-16 0* 



been living in the Insectary for twenty-one months, its food 

 consisting of Searabasid and other beetle grubs with similar 

 habits of working under the surface of the soil, most of 

 them damaging roots of plants. 



As mentioned in last year's report, Bruchus affinis was 

 observed to lay eggs extensively on pea-pods at Pusa in 

 January and February, so that the peas may be infected in 

 the field before being stored. The habits of this beetle 

 have since been investigated more thoroughly. The grubs 

 are brought into the store inside the seeds which are exter- 

 nally quite sound at harvest -time, about the end of 

 January. The beetles begin to emerge from the seeds in 

 August, but they do not become active until about Decem- 

 ber or January, the majority of the beetles remaining inside 

 the seeds and thus having a chance of being taken back to 

 the field at sowing-time. Seeds from pods on which eggs- 

 were laid suffered to the extent of about 50 per cent, of the 

 crop, whilst the remainder of this same crop (after separa- 

 tion of those pods with visible eggs) suffered a damage of 

 oniy 3-5 per cent., and this was probably due to a small per- 

 centage of eggs being passed over. Treatment with Carbon 

 Bisulphide or Naphthaline successfully prevented damage 

 to the peas in store. A simple treatment (immersion of the 

 seeds in water, when those attacked float and the unattacked 

 seeds sink) has been found efficient for separation of the 

 affected from the unaffected seeds and therefore it is pos- 

 sible to avoid liberation of the beetles in the field at the 

 sowing time. 



Bruchus chinensis breeds throughout the year in Pulse 

 seeds in store. This insect has been observed to breed in 

 Gram, Mung (Phaseolus mungo), Urid (P. radiatus), Bakla 

 (P. aconitifolius), Kulthi (Dolichos biflorus), Lentil, 

 Khesari (Lathy rus sativus), Arhar (Cajanus indicus), Bora 

 (Vigna catjang), and large and medium peas. A small 

 variety of local indigenous pea has been found to be immune 

 from its attack. Eggs are laid on this variety as on others, 

 but the grubs cannot bore or feed in this pea, which is, how- 

 ever, more liable to attack by Bruchus affinis in the field. 



