First results concerning the efficacy of entomopathogenic nematodes against Hercinothrips femoralis (Reuter)

English. The efficacy of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis bacteriophora against larvae and adults of banded greenhouse thrips, Hercinothrips femoralis, was studied under laboratory conditions. The activity of the biological agents under study was determined at three different temperatures (15, 20, and 25°C), with concentration of 200 infective juveniles per individual (larva or adult), a day:night ratio of 4:20 and relative humidity of 95 %. The experiment was conducted in plastic rearing vessels on French bean leaves with a slightly modified version of a method used for studying the bionomics of thrips. The mortality rate of the thrips was determined four days after the application of the nematode suspension. Temperature had significant influence on adult pest mortality, but no significant effects were found with nematode species. Neither temperature nor nematode species had significant effect on larval mortality, which ranged from 23 % (S. feltiae at 25°C) to approximately 50 % (H. bacteriophora at 15 and 25°C). Mortality of adults was significantly influenced only by temperature, with the nematodes being most efficient at 25°C (approximately 30 % mortality by H. bateriophora). The results of our research showed that foliar application of entomopathogenic nematodes might be a relatively efficient way for controlling H. femoralis, but the optimization of environmental factors would likely improve their efficacy further.

Slovenian. V laboratorijskih razmerah smo preučevali učinkovitost entomopatogenih ogorčic Steinernema feltiae in Heterorhabditis bacteriophora za zatiranje ličink in odraslih osebkov resarja Hercinothrips femoralis. Delovanje ogorčic na _u_elko smo ugotavljali pri treh različnih temperaturah (15, 20 in 25°C), koncentraciji 200 infektivnih ličink/osebek, razmerjem med svetlobo in temo 4:20 in 95% relativni zračni vlagi. Poskus smo izvajali v plastičnih gojitvenih posodicah na fi_olovih listih, z rahlo modificirano metodo, ki je bila primarno razvita za raziskave bionomije resarjev. _tiri dni po aplikaciji suspenzije ogorčic smo ugotavljali smrtnost izpostavljenih resarjev. Med vrstama ogorčic nismo ugotovili signifikantnih razlik v delovanju na _kodljivca. Vrsta ogorčic in temperatura nista imeli signifikantnega vpliva na smrtnost ličink, ki je zna_ala od 23% (S. feltiae pri 25°C) do pribli_no 50% (H. bacteriophora pri 15 in 25°C). Smrtnost odraslih osebkov je bila signifikantno determinirana le s temperaturo, pri čemer so bile ogorčice najbolj učinkovite pri 25°C (pribli_no 30% smrtnost pri H. bacteriophora). Rezultati na_e raziskave ka_ejo, da je lahko foliarna aplikacija preučevanih biotičnih agensov relativno učinkovit način zatiranja resarja H. femoralis, z optimiziranjem okoljskih dejavnikov pa je mogoče njihovo učinkovitost _e izbolj_ati.