Study On Natural Enemies Of Sirex Noctilio And Biology Of Its Dominant Parasitic Wasp

To verify the new natural enemies species of invasive pest Sirex noctilioFabricius in China,determine the dominant parasitic wasp and its biological figures and provide a theoretical basis for determining the optimal control period and biological control agents.Systematical research was conducted by field investigation combined with laboratory observation and rearing from 2015 to 2016 in Hegang,Heilongjiang.The results showed that there were 3 kinds of natural enemies to Sirex noctilio,including parasitic wasps,pathogenic fungi and nematode.Of which:5 species of parasitic wasps(Rhyssa persuasoriaPersuasoria(Linnaeus),Ibaliidae,Ibalia leucospoides leucospoides(Hochenwarth),Ibalia rufipes drewseni Borries and Pseudorhyssa nigricornis(Ratzeburg)),2 species of pathogenic fungi(Trichoderna atroviride Bissett and Trichoderma viride Persoon)and a nematode(Deladenus siricidicola Bedding).Of which:R.persuasoria persuasoria was determined as the dominant species of parasitic wasp.By further indoor rearing,we find that the wasp have one generation a year,oviposited in larvae or older instar host larvae.It has a strong ability of rain-wash resistance and a good adaptability to natural environment.The above-mentioned results show that R.persuasoria persuasoria(L.).is an important insect species of natural enemies for controlling S.noctilio and the most appropriate control period is larvae or older instar larvae.What's more,based on the parasitic rate and effect,D.siricidicola would be considered as the primary control method for Rhyssa persuasoria persuasoria,which should take further research and make emphasis on its development and utilization.