POTENTIAL OF ANTI-FEEDANTS TO CONTROL LARVAL FEEDING OF SELECTED NEODIPRION SAWFLIES (HYMENOPTERA-DIPRIONIDAE)

Antifeedants for controlling larval feeding of several Neodiprion sawflies were evaluated in laboratory and field studies. Nine commercially available insect antifeedants and a hexane extract of the juvenile foliage of jack pine, Pinus banksiana Lambert, were tested on larvae of 6 spp. [N. swaninei Middleton, N. pratti paradoxicus Ross, N. sertifer (Geoffroy), N. nanulus nanulus Schedl, M. rugifrons Middleton and N. lecontei Fitch]. In laboratory bioassays larvae exhibited varying sensitivity to antifeedants; generally species with monophagous or restricted oligophagous feeding habits were most sensitive. In the laboratory the Swaine jack pine sawfly, N. swainei, had severely restricted feeding, development, survival and fecundity. Triphenyltin hydroxide was toxic to N. swainei and to the European pine sawfly, N. sertifer. In field tests certain antifeedants disrupted N. swainei feeding and development. The colonial behavior of larvae often was disrupted and solitary larvae fell from trees or wandered on twigs. Colony disruption by most antifeedants was temporary and many larvae resumed feeding.