Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore - 641 003, Tamil Nadu, India.
*A part of the approved M.Sc. (Ag.) thesis submitted by B. Ratna kumari to Tamil Nadu Agricultural University, Coimbatore - 641 003, India.
The biology of cotton stem weevil, Pempherulus affinis Faust., was studied on susceptible (MCU 5) and resistant (MCU 3) cotton accessions. The average incubation periods were 7.6 and 7.4 days in MCU 5 and MCU 3 respectively. The mean larval duration was 44.8 days in MCU 5 and 58.6 days in MCU 3. The pest spent an average of 9.1 and 9.5 days in MCU 5 and MCU 3 respectively. The sex ratio was 1:1 in both the accessions. Mean adult longevity was 23 days in MCU 5 and 17.2 days in MCU 3. This suggests that development of the pest was delayed in resistant variety.
