Impact of rutin on growth, development and oviposition of Bt-susceptible and Bt-resistant pink bollworm

The evolution of pest resistance to insecticidal proteins from Bacillus thuringiensis (Bt) restricts the sustainable application of transgenic Bt crops, and exploring other ecofriendly insecticides to efficiently suppress Bt-resistant populations is thus urgently needed. The plant secondary metabolite rutin possesses pest resistance effects and plays an important role in plant resistance to pests, but the effect of rutin on pink bollworms is unclear. We investigated the effects of rutin on two types (Bt-susceptible and Bt-resistant) of pink bollworms (Pectinophora gossypiella). Rutin had significant inhibitory effects on the growth, development, and oviposition of both Bt-susceptible and Bt-resistant strains. For both strains, rutin ingestion by larvae did not significantly affect larval survival at 7 days after treatment or egg hatching rate but significantly decreased pupation rate, eclosion rate, neonate-to-adult survival, pupal weight and eggs per female and significantly prolonged larval developmental periods, and the effect increased with increasing rutin content. The response to rutin ingestion was basically consistent between Bt-resistant and Bt-susceptible strains, indicating that the Bt-resistant strain did not exhibit cross-resistance to rutin. These results provide a reference basis for green control and resistance management of pink bollworms and may be used as a component of comprehensive management for this pest.