Vegetos

Abstract

Insecticide imidacloprid and entomopathogenic nematode (EPN), Heterorhabditis indica alone and in combinations of imidacloprid and EPN were evaluated against early and late 3^rd instars of coconut white grub, Leucopholis 3^rd coniophora. Field collected instars white grubs were placed in pots with sweet potato treated with imidacloprid, the EPN, or both. In all nematode-imidacloprid combinations, both early and late 3^rd instars grub mortality was significantly higher than in the H. indica alone and imidacloprid alone treatments. Combinations of imidacloprid and nematodes had a strong synergistic effect on mortality at different concentrations of imidacloprid. Nematodes were admixed with various concentrations of imidacloprid ranging from 0.04 to 1.25% could not significantly affect the survival of infective juveniles resulting in only a negligible mortality (3.5%). Results revealed that different imidacloprid concentrations, exposure time and interaction between imidacloprid and exposure time not affected nematodes mortality in bioassay. Combinations of imidacloprid and entomopathogenic nematodes may provide a powerful and economically feasible curative control in white grub management in coconut.