Compatibility of some soluble fertilizers used in drip irrigation with entomopathogenic nematode Heterorhabditis indica Poinar, Karunakar & David

Heterorhabditis indica Poinar, Karunakar& David (Rhabditida: Heterorhabditidae) is used in biological control of insect pests as it specifically targets the larval stages of insects. Entomopathogenic nematodes can be affected by agronomic practices such as fertilization, tillage and irrigation. The objective of this study was to determine the direct effects of soluble fertilizers on H. indica. Four common inorganic fertilizers that are used extensively in drip irrigation were selected for the study. These fertilizers were tested at four concentrations (25, 50, 100, 200 ppm) under laboratory conditions and checked for mortality and infectivity for 5 days. Urea phosphate was found to be the most lethal, as compared to other fertilizers. There was a positive correlation between concentration of fertilizer and mortality of infective juveniles (IJs) of H. indica. H. indica infectivity reduced with an increase in concentration of fertilizer solution after 1, 3 or 5 days. Infectivity of H. indica decreased with increase in incubation time from 1 to 3 and further to 5 days.