Seasonal Variations in the Biology of Lesser Grain Borer Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) on Stored Maize under Laboratory Conditions
KM Ajaykumara, GT Thirumalaraju and Anjali AS
Laboratory experiments were conducted during kharif 2014 (July-August), rabi/winter 2014 (November-December) and summer 2015 (April-May) seasons at Agricultural Entomology laboratory, UAS, GKVK, Bengaluru to study the seasonal variations in the biology of the R. dominica. The results revealed that the mean incubation period of 9.64 and 7.56 days, the mean duration of first instar grub was 10.44 and 8.28 days, second instar – 9.32 and 7.48 days, third instar – 9.24 and 7.28 days and fourth instar – 10.34 and 8.24 days during kharif and summer seasons, respectively. Total grub period occupied relatively longer duration of 39.32 days during kharif, while in summer it with shorter duration of 31.28 days. The male and female adult beetles respectively lived for longer duration of 26.08 and 28.64 days in kharif season and for shorter duration of 19.52 and 21.88 days during summer seasons. The mean total life cycle occupied 60.96 and 49.76 days during kharif and summer seasons, respectively.