Pyriproxyfen activates reproduction in prediapause northern strain plum curculio (Conotrachelus nenuphar Herbst)

Field-collected, prediapause northern strain plum curculio, Conotrachelus nenuphar (Herbst), adults were treated with the juvenile hormone analogue pyriproxyfen to assess effects on reproductive development. Adults of this pest have an obligate winter reproductive diapause and do not reach reproductive maturity until after spring emergence. Topical (1.0 microL) doses of 10, 1.0 and 0.1 microg microL(-1) pyriproxyfen induced oocyte development and reproductive maturation in all treated females as assessed by dissection. There was no increased mortality in treated beetles, and control insects showed no reproductive maturation. Treatment of prediapause males and females with 1.0 microg microL(-1) of topical pyriproxyfen or exposure to residues on fruit induced successful egg laying and F1 emergence; F1 pupation success in topical treatments and residue exposure was 47 and 59% respectively. Filial adults require re-exposure to initiate reproductive development. Treatment protocols with pyriproxyfen will allow researchers to culture the northern strain, instead of relying exclusively on the non-diapausing southern strain.