Influence of Temperature on Infectivity of Entomopathogenic Nematodes against Black Cutworm, Agrotis ipsilon (Hufnagel) and Greater Wax Moth, Galleria mellonella (Linnaeus) Larvae

Abstract

Effect of different temperatures on infectivity and progeny production of indigenous entomopathogenic nematode isolates, Steinernema carpocapsae PDBC EN 6.11, S. abbasi PDBC EN 3.1, S.tami PDBC EN 2.1, and Heterorhabditis indica PDBC EN 6.71, PDBC EN 13.3 were studied under laboratory condition against Galleria mellonella (Linnaeus) and Agrotis ipsilon (Hufnagel) final instar larvae. All isolates caused absolute mortality of test insect larvae, and produced progeny at 25 and 32°C. Low rate of infection or no infection was observed at lower temperatures, 15 and 8°C, respectively. Time required to kill host insects by all isolates showed difference at 15, 25 and 32°C. Shortest time for mortality of A. ipsilon and G. mellonella larvae was observed at 32°C followed by 25°C. Absolute mortality of larvae was observed with all isolates after 48 and 72 hours at 25° and 32°C, whereas the same was not achieved at 15°C even after 96 hours post exposure. Progeny production of all isolates varied with reference to temperature. Irrespective of isolates, 25°C was found suitable for infection and development of nematode populations.