Efficacy of chitin inhibitor and Bacillus thuringiensis Ber. used either alone or in combination with certain insecticides against Spodoptera litura Fab. infesting sunflower.

The efficacy of three conventional insecticides, viz., profenofos 0.05%, methomyl 0.05% and cypermethrin 0.01% and a neem product 0.1% (Nivaar 1500 EC) either alone or in combination with the chitin inhibitor, lufenuron 0.01% (Match 50 EC), and biopesticide, Baccillus thuringiensis var. Kurstaki 0.15% (B.t.k.) at half of their recommended concentrations, and the combination insecticide cypermethrin 0.005% + profenofos 0.066% (Polytrin ‘C’ 44 EC) individually was evaluated against Spodoptera litura Fab. infesting sunflower. During rabi 1996–97, the crop was sprayed twice. The combinations of lufenuron with each of the three insecticides, viz., cypermethrin, profenofos and methomyl were more effective in reducing the larval population of S. litura, being 59.47, 51.90 and 49.88 per cent, respectively. This was followed by combinations of B.t.k. with each of these three insecticides, the reduction in larval population being 54.97, 48.51 and 46.27 per cent, respectively. When cypermethrln and Polytrin ‘C’ (cypermethrin + profenofos) were sprayed individually, the reduction in larval population was more than 50%, being 56.80 and 51.96 per cent, respectively. Although the invidvidual treatments of profenofos and methomyl were effective on day 2, the efficacy decreased from eighth day arter spraying. B.t.k., followed by Nivaar was least effective.