Beauveria bassiana affects immature stage development of Prostephanus truncatus (Coleoptera: bostrichidae) in stored maize

ABSTRACT

Recent research in Ghana has demonstrated the effectiveness of an isolate of B. bassiana, sensu lato (IMI 389521) from the U.K. against the larger grain borer Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), a major pest of stored maize. To determine whether this isolate is effective on immature stages of P. truncatus, a laboratory study of the response of immature stages (egg, larvae and pupae) of P. truncatus in maize grains to two concentrations (1 × 10⁹ and 3.16 × 10⁹ cfu/kg maize) of B. bassiana, IMI 389521 formulated with Entostat™ and kaolinite was undertaken. Adult emergence, per cent survival of adults that emerged and the number of larvae in each immature stage were assessed after 45 days. Apart from the egg experiment, higher numbers of adults emerged in grains containing larvae and pupae treated with B. bassiana product compared to the untreated maize control. This notwithstanding, survival of emerged adults of P. truncatus was greatly reduced in B. bassiana treatments (<10%) compared with 75–95% in the controls. Surface treatment with B. bassiana on pre-infested maize showed a significant effect on the developmental biology of P. truncatus in Ghana.

KEYWORDS:

• Beauveria bassiana
• Prostephanus truncatus
• bostrichidae
• biocontrol agent
• larger grain borer

Acknowledgements

We are also grateful to Mr. Raymond Glikpo of (PPRSD/MOFA) and staff of Department of Crop Science, University of Ghana, Legon, who offered technical assistance during the trial.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by Bill and Melinda Gate Foundation [grant number OPP1052676] with support from Exosect-U.K., Agrauxine-France, CABI/Europe-U.K. and CABI/WA.