Storage and efficacy of entomopathogenic nematode species as a biocontrol agent against the armyworm, Spodoptera litura (FABRICIUS) (Lepidoptera: Noctuidae)

Abstract

BackgroundThe armyworm, Spodoptera litura (FABRICIUS) (Lepidoptera: Noctuidae) is a widely distributed polyphagous pest that is seriously affecting more than 100 different hosts. Globally, biopesticides are becoming the mainstream as chemicals and biocontrol agents gain more of the market share every year, because some of these biocontrol measures prevent the economic disruption of food crops.ResultsFor storage, 3 substrates were tested for entomopathogenic nematodes (EPNs), viz., polyether polyurethane sponge, distilled water and soil. Best storage medium was found to be polyether polyurethane sponge for 2–12 months of storage at 15–18 °C. For biocontrol evaluation four species of Steinernematidae; Steinernema pakistanense, S. siamkayai, S. ceratophorum and S. bifurcatum, and one species of Heterorhabditidae; Heterorhabditis indica, were used against the armyworm. At 350 IJs/ml S. pakistanense; S. siamkayai, S. ceratophorum, S. bifurcatum and H.indica, showed 95, 78, 74, 90 and 87% mortality, respectively.ConclusionsNematode species, long-term storage and shelf life are important considerations for the success of EPNs against target insect pests which in turn are a prerequisite for successful commercialization and this can be achieved by maximum survival of IJs in a formulation for a long period before their utilization in the field.