Activity of entomopathogenic nematodes (Rhabditida) against cereal leaf beetle (Oulema melanopus [L.], Coleoptera, Chrysomelidae) adults under laboratory conditions | Delovanje entomopatogenih ogorčic (Rhabditida) na odrasle osebke rdečega žitnega strgača (Oulema melanopus [L.], Coleoptera, Chrysomelidae) v laboratorijskih razmerah

anglais. In 2009, three Slovenian strains of entomopathogenic nematodes) and commercial product Entonem (active ingredient S. feltiae), were tested under laboratory conditions for their activity against adult cereal leaf beetles (Oulema melanopus). The nematode strains were tested at four different doses (250, 500, 1000, and 2000 infective juveniles/adult) and at three temperatures (15, 20, and 25 ?C). Steinernema carpocapsae strain C101 was the most effective and showed itself to be a good alternative to chemical insecticides, and appears to have the highest potential for controlling overwintered cereal leaf beetles under field conditions. In our bioassay the temperature had the greatest influence on the efficacy of the entomopathogenic nematode strains; both S. feltiae treatments (strain B30 and Entonem) proved to work better at the lowest temperature, however the strain H. bacteriophora D54 had its best efficacy at the highest temperature in the experiment. Several species (S. feltiae and S. carpocapsae) have been efficient at lower suspension concentrations, which enables their economical usage against the cereal leaf beetle in integrated cereal production in the future.

slovène. V letu 2009 smo v laboratorijskem poskusu preizkušali učinkovitost treh domačih ras entomopatogenih ogorčic in komercialnega pripravka Entonem (aktivna snov S. feltiae) zoper odrasle osebke rdečega žitnega strgača (Oulema melanopus). Delovanje entomopatogenih ogorčic smo preizkušali pri štirih različnih koncentracijah (250, 500, 1000 in 2000 infektivnih ličink/osebek) in treh različnih temperaturah (15, 20 in 25 ?C). Rasa C101 vrste Steinernema carpocapsae je bila najbolj učinkovita in bi lahko predstavljala dobro alternativo kemičnim insekticidom pri zatiranju prezimljenih odraslih osebkov rdečega žitnega strgača na prostem. V našem poskusu je imela največji vpliv na delovanje entomopatogenih ogorčic temperatura; obe obravnavanji z vrsto S. feltiae (rasa B30 in Entonem) sta bili učinkoviti tudi pri nižjih temperaturah, rasa D54 vrste H. bacteriophora pa je najbolje delovala pri najvišji temperaturi v poskusu. Ogorčici S. feltiae in S. carpocapsae sta zadovoljivo učinkovali tudi pri nižji koncentraciji suspenzije ogorčic, kar omogoča večjo gospodarnost rabo njihove uporabe pri zatiranju odraslih osebkov rdečega žitnega strgača v integrirani pridelavi žit v prihodnje