Impact of Abiotic and Biotic Environmental Conditions on the Development and Infectivity of Entomopathogenic Nematodes in Agricultural Soils.

Abstract

Many organisms, including beneficial entomopathogenic nematodes (EPNs), are commonly found in the soil environment. EPNs are used as biopesticides for pest control. They have many positive characteristics and are able to survive at sites of application for a long time, producing new generations of individuals. The occurrence of populations depends on many environmental parameters, such as temperature, moisture, soil texture, and pH. Extreme temperatures result in a decrease in the survival rate and infectivity of EPNs. Both high humidity and acidic soil pH reduce populations and disrupt the biological activity of EPNs. Nematodes are also exposed to anthropogenic agents, such as heavy metals, oil, gasoline, and even essential oils. These limit their ability to move in the soil, thereby reducing their chances of successfully finding a host. Commonly used fertilizers and chemical pesticides are also a challenge. They reduce the pathogenicity of EPNs and negatively affect their reproduction, which reduces the population size. Biotic factors also influence nematode biology. Fungi and competition limit the reproduction and survival of EPNs in the soil. Host availability enables survival and affects infectivity. Knowledge of the influence of environmental factors on the biology of EPNs will allow more effective use of the insecticidal capacity of these organisms.