Effect of various physical and chemical stress conditions on the infectivity and survival of Heterorhabditis indica and Steinernema feltiae: Relationship with lipid oxidative stress

Abstract

Entomopathogenic nematodes (EPNs) of the genera Heterorhabditis and Steinernema represent an alternative for the biological control of insects. The limited half-life of EPNs is still one of the most concerning issues in their commercialization. Lipid peroxidation (LPO) caused by reactive oxygen species (ROS) may be one of the most important causes of loss of infectivity and survival of EPNs when exposed to various physicochemical stress conditions (temperature, pH, hypoxia and osmotic pressure). Because LPO generates free radicals (FRs), it can trigger membrane peroxidation and lipid energy reserves of EPNs. However, in EPNs there is no data on the role of LPO on their physiology, making strategies for the conservation of derived biopreparations difficult. In this sense, the influence of LPO on the species of EPNs S. feltiae and H. indica under various conditions of physicochemical stress was studied. In both EPNs, the proposed stress conditions altered infectivity and survival over time, generating ROS associated with LPO with a variable tolerance depending on the species, type and time of exposure to stress. A relationship was observed between the LPO induced by stress conditions and infectivity-survival.