Oulema melanopus (L.) (Coleoptera: Chrysomelidae) adults are susceptible to entomopathogenic nematodes (Rhabditida) attack: results from a laboratory study

Abstract

Three species of entomopathogenic nematodes from Slovenia (Steinernema feltiae B30, S. carpocapsae C101, and Heterorhabditis bacteriophora D54) and commercial product Entonem (S. feltiae as active ingredient) were tested under laboratory conditions for their ability to kill adult cereal leaf beetles (Oulema melanopus). The nematode strains were tested at 250, 500, 1000, and 2000 infective juveniles/adult and at 15, 20, and 25°C. The numbers of beetles killed were recorded 2, 4, and 6 days after treatment. S. carpocapsae strain C101 was the most effective and showed itself to be a good alternative to chemical insecticides (at 2 DAT 100% mortality was recorded), and appears to have the highest potential for controlling overwintered cereal leaf beetles under field conditions. The temperature had the greatest influence on the efficacy of the entomopathogenic nematodes; both S. feltiae strains proved to work better at the lowest temperature, however the strain H. bacteriophora D54 had its best efficacy at the highest temperature. S. feltiae and S. carpocapsae have been efficient at lower suspension concentrations, which enables their more economical usage against the cereal leaf beetle in integrated agriculture practice in the future.