Characterizing the sub-lethal effects of two insect growth regulators on plum curculio, Conotrachelus nenuphar (Herbst), in apples and cherries

With the implementation of Food Quality Protection Act 1996, fruit growers are forced to use pesticides that are becoming available in the form of reduced-risk and organophosphate-alternative compounds. Two of newly registered compounds, novaluron and pyriproxyfen, from a class of insecticides categorized as insect growth regulators were investigated in laboratory and field for their potential sub-lethal performance against plum curculio. Adult exposure to novaluron reduced the number of viable eggs in laboratory bioassays. Field trials have also shown this sub-lethal activity when adults were exposed to sprayed shoots containing either fruits or leaves. In case of sprayed fruit exposure, novaluron sub-lethal activity lasted up to 14 d post spray. Pyriproxyfen reduced the survival rate of overwintering northern strain plum curculio. Both novaluron and pyriproxyfen have shown unique sub-lethal activity that can be utilized in apple and cherry IPM, but more investigation is needed to determine the applicability of these compounds.