Pathogenicity of local Metarhizium anisopliae var. acridum strains on Locusta migratoria migratorioides Reiche and Farmaire and Zonocerus variegatus Linnaeus in Senegal

Abstract

Locusts and grasshoppers are the most important economical threat in the sahelian agricultural system. Principal control strategies of these pests are synthetic chemicals which are, however, harmful to the environment and human health. Metarhizium anisopliae based biopesticide Green Muscle IMI330189 has been recently developed for the control of locusts and grasshoppers. In this paper, we assessed the pathogenicity of three local strains of M. anisopliae var. acridum on Locusta migratoria migratorioides and Zonocerus variegatus, in comparison to the commercial product, IMI330189. There was various level of pathogenicity within the strains on the two pests. On L. migratoria, DPV5 caused the highest mortality after three weeks (91.2%). There was a significant difference between DPV5 and IMI330189. However, there were no significant differences between IMI330189 and the other strains. On Z. variegatus there were no significant differences between IMI330189 DPV5 and DPV10. DPV15 had the lowest pathogenic activity. Moreover, the comparison of susceptibility of both insect pests to Metarhizium strains showed that L. migratoria is more susceptible than Z. variegatus. DPV5 had the shortest LT₅₀ on L. migratoria 7.1 days whereas on Z. variegatus, the LT₅₀ value of DPV5 was comparable to IMI330189. Our study suggests that, DPV5 which was isolated from Kraussaria angulifera in Senegal is a promising candidate for future development for locusts and grasshoppers control in the country.

Keywords: Green Muscle, African migratory locust, grasshoppers, local strains, biopesticides