Influence of environmental factors on the biology of tamarind bruchid, Caryedon serratus (Olivier) on groundnut

A laboratory experiment was carried out at the Department of Seed Science and Technology, Seed Research and Technology Centre, Rajendranagar, Hyderabad to study the influence of seasonal variations on the life stages of Caryedon serratus under ambient storage conditions both on the pods as well as kernels of groundnut for the efficient management of this pest throughout the year. The variations in the duration of each stage was correlated with the environmental factors like temperature and relative humidity. The January-February months, with 26.76°C maximum and 24.63°C minimum temperatures and 76.00% relative humidity recorded maximum durations for egg (14.60 days), larva (49.00 days), pupa (15.00 days) and adult longevity (21.60 days). Higher per cent of egg viability (58.80), larval survival (56.80) and adult emergence (86.60) were recorded during September-October during which lowest relative humidities (73.11% and 71.40%, at 7 am and 2 pm, respectively) were recorded. November-December recorded higher fecundity (29.20 eggs female−1) when the minimum temperature was lowest (22.66°C). The period from September to February with 30.73–26.76°C and 22.66–25.75°C, maximum and minimum temperatures, respectively and 71.40–76.00% relative humidity was found to be most optimum and congenial for the bruchid growth and development. These findings revealed that proper control strategies could be planned for the management of Caryedon serratus from September to February to avoid post harvest losses in stored groundnut.