Abstract
The sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae), is a destructive insect pest that damages sweet potatoes both in the field and during storage. To identify new environmentally friendly insecticides to control this insect pest, three assays (olfactory test, anti-feeding assay, and toxicity assay) were conducted to evaluate the efficacy and mode of action of 10 botanical insecticides against C. formicarius adults in 2015 and 2016. Of these 10 botanical insecticides, tea saponin, pyrethrins, and veratrine showed significant repellency in olfactory tests. Eight botanical insecticides showed anti-feeding effects in the feeding choice test. Five botanical insecticides had high toxicity. Among them, the lethal concentrations of rotenone were lowest followed by pyrethrins. The lethal time values of rotenone were shortest followed by nicotine. In conclusion, rotenone, pyrethrins, nicotine, and toosendanin have the potential to control C. formicarius adults. Of these, pyrethrins and toosendanin are more environmentally friendly than rotenone and nicotine and were identified as better insecticides to control C. formicarius. Key words: Toxicity, repellency, anti-feeding, Coleoptera, Brentidae, environmentally friendly insecticides.
Highlights
The sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae), is an important insect pest of the sweet potato, Ipomoea batatas (L.) Poir
The results of olfactory tests showed that tea saponin, pyrethrins, and veratrine had significant repellence effects against weevils
Antifeedant assay showed that pyrethrins and toosendanin had strong antifeedant activity
Summary
The sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae), is an important insect pest of the sweet potato, Ipomoea batatas (L.) Poir. C. formicarius attacks sweet potatoes both in the field and during storage, causing significant damage and yield losses between 3 and 80% (Kandori et al, 2006). Adult C. formicarius damage the vines, crowns, petioles, and storage roots of sweet potatoes, and the females lay their eggs under the epidermis of older portions of vines and storage roots. The larvae dug tunnels into the vines and storage roots, into which they excrete feces (Reddy et al, 2014). Feeding injuries disrupt the translocation of water and nutrients in plants and induce storage roots to produce terpenoids and phenolic compounds, which.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
