No abstract

Oil seed crops are gaining a momentum in cultivation after cereals and pulses. Among the oilseed crops rapeseed-mustard occupies a prominent place both in cultivation and production. In India it grows predominantly in Rajasthan,

Laboratory experiments were carried out to study the biology of Sitophilus oryzae on four different wheat germplasms such as (DPW-62150, DBW-39, GW-322, and K-0307). It was found that the different developmental stages of rice weevil were longer during the winter season as compared to the summer season. As lowest incubation period of 3±0.47 days was recorded from DPW-62150 while the longest one from DBW-39 with 5.44±0.42 days. The lowest total larval and pupal period was registered in germplasm DPW-62150 (23 days) while it was highest (34.44±0.42days) in DBW-39. Total life cycle of male with food was lowest in GW-322 with 84.10±0.83 days while it was highest with 95.43±0.80 days in DBW-39; similarly for female with food the lowest and longest of life cycle was noted on the same germplasm with 110±0.82 days and 123.10±0.83 days respectively. When the male and female adults were devoid of food, the life cycle of male and female was lowest on DPW-62150 and highest on DBW-39 with 40.00±0.82 days and 44.33±0.94 days and 53.43±0.61 days and 60.43±0.8 days respectively during summer and that of winter with incubation period of 7.67±0.47 days in DPW-62150 to 11.00±0.82 days in DBW-39. Total larval and pupal period varied from 34.67±0.47 days to 42.33±0.47 days in DPW-62150 and K-0307 respectively. Total life cycle of male with food ranged from 104±0.94 days (DPW-62150) to 110.33±0.94 days (DBW-39) while for the female the range was form 128.00±0.82 days (GW-322) to 137.33±1.25 days (K-0307). On the other hand total life cycle of the male devoid of food to adult, ranged from 56±0.82 days to 66.67±0.94 days while the same for female was from 60.33±0.47 days to 73.67±0.94 days.

Laboratory experiments were carried out to study the effect of different colours of storing containers on the infestation of Sitophilus oryzae on stored rice grains during 2018-19. The results of the present investigation reveals that at 90 days after storage maximum grain infestation (%) was recorded in Mohanbhog (47.66%) followed by Seshphal (40.07%) while the lowest infestation was noted in Jhagarikartik (34.58%). When the effect of colour of the storage containers was considered, the black container showed the highest % of infested grains (48.86%) followed by blue (42.61%) and green (38.65%) container while the lowest grain infestation was recorded from the transparent container (32.96%) at 90 days after storage. Same trend was also noted at 30 and 60 days after storage. Likewise Mohanbhog again registered the highest weight loss percent with pooled mean values 34.98% at 90 DAS respectively which was followed by Seshphal (32.62%) and Jhagarikartik (30.94%) respectively. It also reveals that black coloured storage container registered the highest weight loss percent (40.70%) followed by blue coloured storage container (35.68%), green storage container (31.70%), whereas the least weight loss percentage was registered from the transparent storage container (23.31%) at 90 DAS. This trend was always observed at 30 and 60 days after storage of rice grains. When the germplasms and the coloured containers were considered together, the S. oryzae reared under Mohanbhog in black containers produced the highest population while the S. oryzae reared under in Jhagarikartik in transparent containers showed the lowest weevil population.

Laboratory experiments were carried out for two years to study the effect of different storage materials on the infestation of Sitophilus oryzae on stored rice grains using different storage containers namely gunny-bags, polythene-bags, cloth-bags, polythene coated cloth-bags and earthen pots. Considering the storage material from the present studies, cloth bags registered the highest damaged grain percent with 39.47% at 90 DAS while the lowest was recorded from the polythene bags with 28.31%. At the same time greatest grain weight loss was also recorded from the cloth bags (32.00%) and the lowest from the polythene bags (21.16%). It is also noticed from the results that among the storage materials used, highest population was registered from the cloth bags (435.89 adults) while the lowest population was noted from the polythene bags (303.00 adults) (pooled mean data) at 90 DAS.