Evaluation of botanicals and synthetic insecticides against eucalyptus gall wasp, Leptocybe invasa (Eulophidae: Hymenoptera).
A field experiment was conducted during the kharif of 2008 in a 2-year-old Eucalyptus plantation in Sirsi, Karnataka, India, to evaluate the efficacy of carbofuran 3G (0.5 or 1.0 g per plant), methyl parathion 50 EC [parathion-methyl] (1.0 ml/litre), imidacloprid 17.8 SL (0.25 ml/litre), 300 ppm Multineem (2.5 or 5.0 ml/litre), 5% soapnut (Sapindus spp.) aqueous extract (50 g/litre), and Multineem and soapnut (5 ml + 50 g/litre) against L. invasa. The insecticides were more effective in the reduction of gall formation than the plant-based treatments. The spot application of carbofuran 3G at 0.5 (4.3 galls per 10-cm twig) and 1.0 g per plant (4.7), foliar spraying of methyl parathion (4.3) and imidacloprid (4.0) resulted in the lowest number of galls. At 15 DAFS, foliar spraying of imidacloprid (4.7), carbofuran 3G at 0.5 (8.0) and 1.0 g per plant (6.0), and methyl parathion (6.0) registered the lowest number of galls. On average, imidacloprid was the most effective among the treatments (6.0), followed by methyl parathion (8.5). The mean number of galls varied from 17.9 to 22.5 for the plant-based treatments, and 23.7 for the untreated control.