Chronobiological Management of Pulse Beetle Callosobruchus Maculatus Fab. (Coleoptera: Bruchidae)
The activity pattern of most of the insects follows circadian rhythm, with characteristic ebbs and flow. The
external activity pattern is based on inner metabolic changes that alter the receptiveness of the insects. The sensitivity of
insects to insecticides varies during different times of the day. In this study, the synthetic pyrethroid, deltamethrin is sprayed
on Callosobruchus maculatus (Fab.) during early photophase (6 a.m), late photophase (12 noon); early scotophase (6 p.m)
and late scotophase (12 midnight). The toxicity response varied with variations in the timing of pesticide application. C.
maculatus adults were highly susceptible during early scotophase, when they seemed to be most active. Even at a reduced
dose, a high response was observed during the early scotophase, indicating the need to spray pesticides at the appropriate
time, when the pests are most vulnerable.
Index Terms— Pesticide, Chronotoxicity, Susceptibility.