The potential of entomopathogenic nematodes of the genera Steinernema and Heterorhabditis for biological control of the pine lappet moth Dendrolimus pini L. (Lepidoptera: Lasiocampidae) in Scots pine stands

Protecting stands of Scots pine (Pinus sylvestris) from the larvae of the pine lappet moth (Dendrolimus pini) has been a problem for many years in Central Europe. The feeding habits of the larvae of D. pini often result in more than 50 per cent defoliation, which weakens trees and increases their susceptibility to unfavourable environmental conditions. The aim of this study was to evaluate the effectiveness of native isolates of the entomopathogenic nematodes Steinernema feltiae (Filipjev, 1934) and Heterorhabditis megidis (Poinar, Jackson and Klein, 1987), as well as of the commercial preparations Nemamax (Heterorhabditis downesi) (Stock, Griffin and Burnell), Entonem (S. feltiae) and E-nema GmbH (S. carpocapsae) in greenhouse experiments and field trials. The highest extensity of infection (>80 per cent) of the pine lappet moth with nematodes in the greenhouse experiments studies was found for the strain S. feltiae ZAG15. In field trials, a greater effectiveness was obtained using commercial preparations of S. feltiae (Entonem), which led to approximately a twofold reduction in the number of wintering D. pini larvae. The results of this study indicate that entomopathogenic nematodes can be considered a potential biological control agent for reducing the damage caused by D. pini larvae.