Abstract
The discovery of the harmful effects of chemical plant protection products used in agriculture on human, animal and environmental health has led to a reduction in their use and the development of new strategies to combat bio-aggressors. One such strategy is biological control, i.e. the use of living organisms to control pests. Entomopathogenic nematodes (EPNs) are capable of killing a large number of insect species in less than 120 hours. They are used in biological control by augmentation and/or acclimatization (introduction of a natural enemy into the environment) on high-value crops (ornamentals, vegetables, orchards). The high cost of their use, as well as the variability of their efficacy, reduces their use in field crops such as corn and wheat. What's more, many factors (soil texture, pH, nematophagous fungi, competitive bacterivorous nematodes, etc.) are known to influence their presence and diversity in soils. Surprisingly few studies have been carried out to describe the effects of agricultural practices on the presence, diversity and persistence of EPNs in agricultural soils.The challenge today is to use EPNs in conservation biological control (using different agricultural practices to encourage the presence of pests' natural enemies). The thesis we are working on has three key objectives:1/ Propose a new methodology to improve the detection of EPNs with a view to describing their description in agricultural soils.2/ Determine the factors influencing the presence of EPNs3/ Determine the factors influencing the success of the parasite cycle in EPNs, and in particular the influence of their microbiota