Preliminary observations on use of Beauveria bassiana for the control of the sweet potato weevil (Cylas sp.) in South Africa

Abstract

Sweet potato weevils (Cylas puncticollis and C. formicarius) are notorious pests of sweet potato and cause severe losses in marketable yield. The study tested the use of Beauveria bassiana ((Balsamo) Vuillemin) (Deuteromycota: Hyphomycetes) for controlling sweet potato weevils. An experiment was conducted using four treatments: 1) dipping sweet potato cuttings in solution of 1 g/litre B. bassiana before planting, 2) spraying with the registered chemical Deltametrin at 50ml/100litre every 2 weeks for four months after planting, 3) spraying the leaves every 2 weeks with B. bassiana (10 g/100 litre) for four months after planting; and 4) a control (sprayed with distilled water). The experimental design was a Latin square with split plot design: pest management strategy as main plot factor and cultivars (Bophelo, Ndou and Blesbok) as subplot factors. Spraying with B. bassiana significantly reduced the percentage of insect damaged roots (5.31%) compared to the control (13.75%). Dipping did not significantly reduce the number of insect damaged roots (12.13%). There was no significant difference between the chemical spray (5.88% insect damage) and spraying with B. bassiana (5.31% insect damage). The preliminary investigation indicated that B. bassiana can be considered as an alternative control method for the sweet potato weevil.

Chromosome-level genome assembly of the sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae) and functional characteristics of CforOBP4-6

“…TheC. formicarius assembly genome size is similar to the mean assembly size of the previously published coleopteran genomes (ranging from 110 to 850 Mb) (Hlerema et al , 2017) and is comparable to the genome sizes ofPlastocerus angulosus (367 Mbp) (Kusy, Motyka, Bocek, Vogler, & Bocak, 2018) andHycleus phaleratus (308 Mbp) (Y. M. Wu, Li, & Chen, 2018).…”

“…Furthermore, the sex pheromone of C. formicarius , (Z)-3-dodecen-1-yl (E)-2-butenoate, was first extracted in 1978 (Coffeltet al , 1978), and the bioactivity of the synthetic compound was tested in both laboratory and field experiments in 1986 (Heath et al , 1986). Olfaction-based approaches, using synthetic sex pheromones to monitor and interfere with the pests' ability to find suitable mates, have been used successfully in "pushpull" control strategies (Hlerema, Laurie, & Eiasu, 2017). However, becauseC.…”

Eco-friendly biopesticide of Beauveria bassiana to control sweet potato weevil Cylas formicarius (Coleoptera: Curculionidae)

“…Therefore, control technology to maintain tuber yield is needed, such as the application of innovative technology using the entomopathogenic fungus B. bassiana in this study. The success of controlling tuber borer pests using the fungus B. bassiana was also reported by [20] then [21], which indicated that the application of biopesticides from the entomopathogenic fungus B. bassiana was more effective and efficient in protecting tuber damage due to attack by C. formicarius. Furthermore, [22] confirmed that the biopesticidal efficacy of the entomopathogenic fungus B. bassiana combined with plastic mulch to cover bunds was very significant in suppressing tuber damage by up to 99% of attacks by C. formicarius larvae.…”

Identification of the key morphological sweetpotato weevil resistance predictors in Ugandan sweetpotato genotypes using correlation and path‐coefficient analysis

“…These results could probably be because of the range of sources of origins and genetic history of the genotypes used in this study. Several authors have reported significant cultivar differences among sweetpotato accessions for many important sweetpotato traits (Karan & Sanli, 2021; Gurmu et al., 2018; Hlerema et al., 2017; Muyinza et al., 2012; Mwanga et al., 2003; Stathers, Rees, Kabi et al., 2003; Stathers, Rees, Nyango et al., 2003). Earlier on, farmers from the major sweetpotato growing districts (Masindi, Kasese, Kabale, Wakiso, Soroti, and Gulu) in Uganda identified six sweetpotato land races that they grow to be resistant to the Cylas spp.…”