EFFECT OF HYDROSTATIC PRESSURE ON THE VIABILITY OF EPN NATIVE ITALIAN STRAINS STEINERNEMA FELTIAE AND HETERORHABDITIS BACTERIOPHORA

The use of entomopathogenic nematodes (EPNs) as a non-chemical treatment system is one of the most modem techniques promoted by the 2008/128/EC standards for the biological control of plant pathogens. The distribution of EPNs could be carried out with the same sprayers used for the distribution of pesticides. This research is focused on the effects of the mechanical stress due to hydraulic compression on EPNs Italian strains, Steinernema feltiae and Heterorhabditis bacteriophora, to assess their residual strength and vitality under laboratory tests. Liquid suspensions of nematodes were subjected to 8 different levels of hydrostatic pressure from 5 to 40 bar. The hydraulic compression test was conducted through a hydrostatic compression system specifically designed for the experimental test. Although correlation curves show an increment of 14% in nematode mortality, the statistical analysis did not show any significant effect of static pressure on the vitality and infectivity of EPNs, that makes them suitable for field application with sprayers. These preliminary positive results on the effects of compression on the viability of EPNs are preparatory to subsequent field tests under high pressure.