Non-target predatory insects can be indirectly exposed to aerial pesticide spraying and fogging to control Monochmus beetles that transmit pine wood nematode, Bursaphelenchus xylophilus. We evaluated potential lethal or sublethal effects of thiacloprid on survival and behavior of a carpenter ant species, Camponotus japonicus Mayr. Field-collected ant colonies were directly exposed to several food items, such as thiacloprid-addicted Monochmus beetles, 10% sugar watered cotton balls contaminated by thiacloprid concentrations, and 10% sugar water. Dead beetle bodies caused no apparent adverse effect through dietary exposure in general, although a few ants were died with paralysis at colony level experiment. At individual level, most ant workers were died within 10 days compared to control group. In contrast, dietary exposure of ants to thiacloprid concentrations showed significant lethal effect with paralysis and impaired walking, especially at 10 and 50 mg/L thiacloprid concentrations. Some intoxicated ants recovered within a few days in 10 and 50 mg/L thiacloprid concentrations, but intoxicated ants were generally shown to be less responsible to enemy ants with low aggressive behavior. Implications for predicting hazards of thiacloprid to beneficial arthropods in pine forests are discussed.

The nematode Bursaphelenchus xylophilus is the causal pathogen of pine wilt disease in Korea. Currently, it is reported that B. mucronatus also has a low pathogenicity. Despite this difference in pathogenicity, it is very difficult to differentiate these two species due to similarity in morphological characters. The sequence variation of internal transcribed spacer (ITS) and intergenic spacer (IGS) regions of ribosomal DNA has been used for species identification and phylogeny of B. xylophilus and B. mucronatus. But, the IGS region sequence data of B. mucronatus has been only reported in Portugal. In this study, We analyzed genetic variation on ITS and IGS regions of B. xylophilus and B. mucronatus (Asian genotype, European genotype) based on rDNA gene sequences, and conducted phylogeography using TCS network. When the each isolates was determined the phylogenetic analysis using the neighbor-joining method, Bursaphelenchus species were divided into each groups, and showed low variation within each species. In the TCS analysis, The isolate of B. xylophilus and B. mucronatus (Asian genotype and European genotype) were divided into each groups and confirmed slightly genetic distance within species. B. mucronatus European genotype has possibility of new species different with Asian genotype.