Efficacy of Two Entomopathogenic Nematode Species as Potential Biocontrol Agents against the Diamondback Moth, Plutella xylostella (L.)

Abstract

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important pest of cruciferous crops in Iran. The susceptibility of P. xylostella larvae to two species of entomopathogenic nematodes (EPNs) (Steinernema carpocapsae and Heterorhabditis bacteriophora) was examined under laboratory conditions. Leaf bioassays were conducted to evaluate the nematode's capability to reach the larvae and kill them. High larval mortality (72.6-96%) was observed in laboratory experiments. The ET₅₀ of H. bacteriophora was higher than that of S. carpocapsae. The ET₅₀ of entomopatpgenic nematodes, H. bacteriophora and S. carpocapsae tested ranged from 21 to 139.7 and 11.3 to 71.4 hours, respectively. The effect of both factors infective juveniles (IJs) and exposure time of 50% (ET50) on the larval mortality was significant (df = 6; P < 0.001) and (df = 2; P < 0.001), respectively. This study revealed that entomopatogenic nematodes (EPNs) have great potential that should be exploited in diamondback moth, P. xylostella management.