Gogoi, IneeBorthakur, Abhilasa Kousik2020-11-032020-11-032019-07https://krishikosh.egranth.ac.in/handle/1/5810154299Field and laboratory experiments were conducted in the Instructional cum Research farm, Department of Agronomy, Assam Agricultural University, Jorhat and Department of Entomology, Assam Agricultural University, Jorhat during 2018-19 to examine the biology of Callosobruchus chinensis (L.) in two different seasons viz., summer and winter considering green gram(variety-Pratap) and blackgram(variety-KU301) as host plants. Ovipositional preference of Callosobruchus chinensis (L.) was also evaluated on four different host plants viz., green gram (variety-Pratap), black gram(variety-KU301), chickpea(variety-JG16) and cowpea(variety-Green fall). The data on biology of C. chinensis (L.) revealed that the insect had a comparatively shorter developmental period in the summer season (April-May) than in the winter season (October-November). In green gram, the fecundity of the insect during summer season was 4.96±0.13 number of eggs while in winter it was 3.60±0.19 number of eggs. The incubation period was found to be 4.92±0.14 days and 6.24±0.13 days during summer and winter respectively. The insect took 17.50±0.12 days to complete its larval period during summer and 23.57±0.18 days during winter. The pupal period was recorded to be 7.53±0.09 days during summer and 9.41±0.07 days during winter. Thus the total developmental period was worked out and noted to be 29.95±0.21 days during summer and 39.22±0.22 days during winter. The longevity of the male was upto 7.73±0.23 days during summer while in winter it survived upto 10.36±0.21 days. The longevity of the female was recorded as 6.70±0.21 days and 8.10±0.27 days during summer and winter respectively. In black gram the mean fecundity was recorded as 3.10±0.12 in summer and 1.57±0.11 in winter. The incubation period was recorded as 5.46±0.12 days and 7.37±0.15 days during summer and winter respectively. The larval period was completed in 18.28±0.08 days during summer and 24.50±0.12 days in winter. The pupal period was 8.17±0.07 days and 10.12±0.12 days during summer and winter respectively. The developmental period was completed in 31.91±0.15 days during summer while it took 42.08±0.21 days during winter. The male longevity was 8.90±0.23 days during summer while 9.40±0.29 days during winter. The longevity of the female was 7.40±0.26 days and 6.80±0.20 days during summer and winter respectively. The data on ovipositional preference revealed that green gram was the most preferred host for egg laying with a mean of 17.40 eggs per four pods, followed by chickpea (14.33), cowpea (11.50) and black gram (8.50). Hatchability percentage was maximum in green gram (90.55%) followed by chickpea (86.24%), black gram (82.86%) and cowpea (81.80%). Maximum adult emergence was observed in green gram (79.16%) and minimum adult emergence was observed in black gram (64.82%). Adult emergence in chickpea was 75.53% and in cowpea it was 76.55%. The data on morphological parameters of the pods revealed that cowpea had the maximum pod length (14.13cm), trichome number/mm2 (14.16) and pod wall thickness (0.73mm) . Correlation analysis between ovipositional parameters and morphological parameters of pods revealed that eggs laid, hatchability percentage and adult emergence had a negative correlation with trichome number/mm2 and pod wall thickness, whereas pod length showed a positive correlation with eggs laid, hatchability percentage and adult emergence percentage. Data on growth parameters revealed that the maximum percentage of reproductive success was shown in green gram (65.52%) followed by Cowpea (55.91%), chickpea (54.56%) and black gram (42.32%). Total developmental period was highest in black gram (33.12 days) followed by chickpea (32.12 days), green gram (31.05 days) and least in cowpea (28.13 days). Growth Index was lowest in black gram (1.96) while the highest was found in cowpea (2.73) followed by green gram (2.56) and chickpea (2.35). Correlation between Growth Index and growth parameters showed that Growth Index was negatively correlated to developmental period and positively correlated to adult emergence and number of eggs laid. A significantly high positive correlation between Growth Index and percentage adult emergence was exhibited by cowpea and chickpea.EnglishThesis