Study on both the life cycle and morphometrics of Sitophilus oryzae on rice cultivar Sampa mashuri in laboratory condition

Somnath Das Choudhury*, Kaushik Chakraborty
Page No. 22-28

Life cycle and biology of the rice weevil S. oryzae on rice grain local variety Sampa mashuri was
observed under laboratory condition covering three consecutive months (June-August) of 2013. The
laboratory temperature ranges from 30.70C and 23.70C and relative humidity from 86 to 69 per
cent respectively. The average length of the adult male and female weevil was 2.9 ± 0.6 mm and
2.8 ±0.6mm respectively. Longevity of adult female with food ranged from 85 to109 days. Weevil
freely copulated under laboratory condition; commenced mating 4 to 6 days after emergence and
subsequently mating occurs. Equally longevity of the adult male was 59-64 days with food. Total
larval period lasted for 22-29 days. The larvae after full grown pupated inside the rice grain. Pupal
period lasted for 7-8 days with a mean of 7.5 ± 0.84 days. Duration of total life cycle starting from
egg to adult ranges 35-49 days with mean of 41.2 ± 5.79 days.
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Keywords: Life cycle, developmental stages, Sitophilus oryzae, rice grain.