Influence of Mechanical Aspects of Distribution on Viability of the Biological Control Agent Steinernema carpocapsae

The distribution of entomopathogenic nematodes (EPNs) for pest control in organic and conventional agriculture is usually carried out with traditional boom sprayers normally used for the distribution of pesticides. Nevertheless there is a reasonable possibility that this operation may induce a state of stress due to sudden pressure changes and mechanical stress, especially during the passage through the pump and nozzles or as a consequence of the effect of hydraulic or pneumatic agitation inside the tank. This work aims to evaluate the effects of some mechanical distribution parameters on the viability of the entomopathogenic nematode Steinernema carpocapsae Weiser which may become significant during the distribution. To assign the mechanical effects to specific components of the distribution, liquid suspensions of the nematode were subjected to different levels of static pressure, and various conditions of agitation and distribution using different types of nozzles. Preliminary results show no significant effect of static pressure on the viability of nematodes. The passage through the nozzles and the use of a elastic rotor pump induces a 7% decrease in viability, but no difference was detected between different nozzles, while the intensity of hydraulic agitation appeared to affect the nematodes viability.