Study on the Biology of Sorghum Chafer, Pachnoda interrupta (Coleoptera: Scarabaeidae) Under Laboratory Condition

Abstract

The duration of egg, larvae, pupae and adults stages of Pachnoda interrupta was studied under laboratory condition (28 ± 2°C), and the life history explained following field observation during 1999 and 2001. Beetles became sexually mature after about ten months in June. Females oviposited singly in the soil and oviposition rate by a single female was 1.75 eggs per day on average and this lasted for more than two months. The peak oviposition took place in July. The hatching period for eggs was 6 to 16 days with a mean of 11.3 days. The duration of the three larval instars was roughly estimated using measurements of the width of head capsule and body length measurements. The larval stage lasted between 41 and 71 days with a mean of 55.7 days. Pupal stages took 11 to 26 days, the average being 18.9 days. Newly emerged beetles activity overlapped with flowering stage of sorghum and other host plants. The adult beetles could live up to 17 months under laboratory condition