African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6401

Full Length Research Paper

Evaluation of ten botanical insecticides against the sweet potato Weevil, Cylas formicarius (Fabricius, 1798) (Coleoptera: Brentidae)

Liyun REN
  • Liyun REN
  • College of Agriculture, Guangxi University, Nanning, China.
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Ganghui ZHENG
  • Ganghui ZHENG
  • Hepu County Agricultural Science Research Institute, Beihai, China.
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Bimei CHEN
  • Bimei CHEN
  • Hepu County Agricultural Science Research Institute, Beihai, China.
  • Google Scholar
Longfei He
  • Longfei He
  • College of Agriculture, Guangxi University, Nanning, China.
  • Google Scholar
Yongmei LIAO
  • Yongmei LIAO
  • College of Agriculture, Guangxi University, Nanning, China.
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Baoshan CHEN
  • Baoshan CHEN
  • College of Agriculture, Guangxi University, Nanning, China.
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  •  Received: 29 June 2020
  •  Accepted: 17 September 2020
  •  Published: 30 November 2020

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.