Definition of functional climatic conditions for the successful use of entomopathogenic nematodes (Nema-Sens) - Subproject C

Entomopathogenic nematodes (EPN) are used worldwide against insect pests in the soil. The potential of EPNs against above-ground insect pests is particularly high, as these have rarely been exposed to EPNs in evolution and thus have not developed defence mechanisms. However, efficacy on plant surfaces is often limited due to a lack of precise information on functional climatic conditions and the response of EPN to changing parameters. The project aims to define optimal application conditions for the use of EPN against overwintering codling moth (Cydia pomonella) larvae in the stem area and against the tomato leaf miner (Tuta absoluta) in the greenhouse in order to expand the use of EPN and reduce the use of chemical insecticides. The aim is to define ranges of the parameters humidity, leaf wetness and temperature at which EPNs find the host insects and kill them. In addition to temperature, leaf wetness duration plays a decisive role. This is determined in particular by rain, dew and overhead irrigation, but also by evaporation-regulating and atmospheric parameters such as wind speed and global radiation. On the leaf, other parameters such as transpiration and leaf structure must also be taken into account.
Today, climate control computers are available in modern greenhouses, which enable climate control according to demand, in order to make the use of EPN against Tuta absoluta successful. Meteorology can provide relatively reliable weather forecasts 3 days in advance. This period is sufficient to deliver EPN and apply it at optimal climatic conditions against Cydia pomonella in the field.
With the definition of suitable environmental conditions, the development of control strategies in the greenhouse and the use of weather data and forecasting models, an optimal use of the potential for the application of entomopathogenic nematodes should be made possible in the future.