Feeding and oviposition preferences of sweet potato weevil,Cylas formicarius elegantulus (Summers), on storage roots of sweet potato cultivars with differing surface chemistries

1989 ◽  
Vol 15 (3) ◽  
pp. 895-903 ◽  
Author(s):  
Stephen F. Nottingham ◽  
Ki -Cheol Son ◽  
David D. Wilson ◽  
Ray F. Severson ◽  
Stanley J. Kays
Keyword(s):  
Sweet Potato ◽  
Potato Cultivars ◽  
Storage Roots ◽  
Cylas Formicarius ◽  
Oviposition Preferences ◽  
Sweet Potato Weevil ◽  
Cylas Formicarius Elegantulus ◽  
Surface Chemistries

scholarly journals Reduced Emergence of Cylas formicarius elegantulus (Coleoptera: Curculionidae) from Sweet Potato Roots by Heterorhabditis indica

2020 ◽  
Vol 113 (3) ◽  
pp. 1129-1133
Author(s):  
Roxana Y Myers ◽  
Charmaine D Sylva ◽  
Cathy L Mello ◽  
Kirsten A Snook
Keyword(s):  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Potato Production ◽  
Field Trials ◽  
Storage Roots ◽  
Heterorhabditis Indica ◽  
Cylas Formicarius ◽  
Virgin Land ◽  
Cylas Formicarius Elegantulus ◽  
Cropping Seasons

Abstract Okinawan sweet potato, Ipomoea batatas, is an important food staple and export crop for the Island of Hawaii. Cylas formicarius elegantulus, sweet potato weevil, is a major quarantine pest that causes severe destruction to the crop. Root malformation and a bitter taste occur when larvae feed and tunnel within the storage root. Off-grade roots are often left in the field after harvest and serve as a reservoir for the weevils. Current management involves the unsustainable practice of moving to virgin land for the next cropping cycle. Strains of Heterorhabditis indica isolated from the Hawaiian Islands were tested for their efficacy at causing mortality of C. formicarius and reducing the emergence of adults from infested roots. In well plate assays, H. indica caused mortality of 88% larvae, 96% pupae, and 4% adults after 48 h. When applied to infested roots, the nematodes caused an average mortality of 78% larvae, 66% pupae, and 32% adults. Greater mortality was observed at the highest inoculum levels (10,000 infective juveniles per storage tuber) but a reduction of 90% inoculum density was still effective at weevil management. In simulated field trials, infestation of storage roots was reduced by 42–99.6% when planted among infested roots that had been inoculated with H. indica. Rates of 2.5 billion IJs/hectare were just as effective as 5 billion IJs/hectare. Application of local H. indica strains in sweet potato production has the potential to manage C. formicarius populations and allow for consecutive cropping seasons.

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