Efficacy of two strains of Entomopathogenic nematodes (Heterorhabditis indica and Steinernema carpocapsae) against Helicoverpa armigera under laboratory conditions.

Abstract

Helicoverpa armigera is known to be an important agricultural pest for several crops due to its mobility, high production rate, and short generation duration. It mainly damages the economic portion of the plant (seeds, leaves, etc.). Efficacy of entomopathogenic nematodes against H. armigera organized as potential biocontrol agents, due to non-toxic effect on other living organisms and the ability to overcome targeted pests. The present study was designed to examine the susceptibility of Helicoverpa armigera to the entomopathogenic. Two species of EPNs (Heterorhabditis indica and Steinernema carpocapsae) were used against different larval stages (2^nd, 3^rd and 4^th) of Helicoverpa armigera using different concentrations. Treatments will be replicated five times in each separate petri plate with one larva. Data was analyzed at a 5% level of significance and subject to statistical analysis. The experimental results were organized with five treatments and five replications in Complete randomized design. The data has been reported on daily basis of time intervals (72 hours) of larval instars (2^nd, 3^rd and 4^th). The results showed that the maximum mortality in 2^nd, 3^rd and 4^th instar larvae of H. armigera after 72 hours were recorded 91.7, 87.6 and 78 %, respectively, when subjected to highest concentration of H. indica (250 IJs/ml) as compared to S. carpocapsae. In conclusion, the study confirms that both EPN species are effective biocontrol agents against H. armigera, with efficacy increasing significantly at higher concentrations.