Division of Entomology, College of Agriculture, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur-482 004, Madhya Pradesh (India).
*A part of approved M.Sc. (Ag.) thesis submitted by S. Vaishampayan Jr. to Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (India).
The minimum feeding period required to lead mortality in the second instar larvae of Heliothis armigera Hub. and Spodoptera litura Fab. fed respectively on leaves of gram and soybean treated with diflubenzuron 0.0125% spray was studied. In the case of H. armigera, 4 hours feeding period gave 100 per cent mortality of larvae seven days after treatment, whereas only one hour was required for S. litura larvae tn obtain 90–100 per cent kill within 7–8 days after treatment.
