Department of Agricultural Entomology, Agricultural College and Research Institute, Madurai-625 104, Tamil Nadu, (India).
The effect of dust formulations of plant oils was evaluated on the development of Sitotroga cerealella (Olivier) and Callosobruchus chinenis on IR 20 paddy grain and cowpea, respectively. Among the seven dust formulations, Iluppai oil 10% D (2%) was more effective in prolonging the development period (38.67 ± 1.53 days). Low adult emergence (79.0/100 g seeds) was recorded in palmarosn oil (PO) + neem oil (NO) + Iluppai oil (IO) 10% D (2%) (1:2:2 v/v/v) which correspondingly reduced the per cent bored grains (12.6%) and weight loss (5.0%), whereas in control, respectively 165 adults/100 g seeds, 26.4% bored grains and 10.4% weight loss were recorded. Palmarosa oil 10% D (2%) was comparatively less effective. Dusts formulated with plant oils were more effective than the plant oils alone against C. chinensis. Cowpea grains treated with PO + NO 10% D (2%) revealed only 3.0 eggs/50 g seeds while plant oils, palmarosa oil and neem oil at 1% recorded 6.5 and 4.5 eggs/50 g seeds, respectively. In spite of seeds treated with neem oil (1%) and PO 10% D (2%) exhibiting more eggs, complete protection to cowpea seeds was observed as evidenced by no adult emergence and weight loss. Iluppai oil 1% and IO 10% D (2%) were less effective against C. chinensis.
