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

Abstract

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.