Metarhizium acridum and Other Entomopathogenic Fungi from Grasshoppers at Arid Sites of Northeastern Mexico

Abstract

Entomopathogenic fungi are important natural enemies of the Orthoptera, insects of great economic impact. We collected 530 live and almost 200 dead grasshoppers near Saltillo, Mexico, during 2007-2010. Less than 1% of live, incubated, and as many as 30% of dead insects were infected by Beauveria bassiana (Bals.) Vuill. sensu lato (in dead insects, coinfection with Entomophaga spp.). Metarhizium acridum (Driver & Milner) Bischoff, Rehner & Humber was observed in live Schistocerca nitens Thunberg adults. Therefore, we enumerated five species of fungi from locusts and other grasshoppers at Saltillo: besides B. bassiana and M. acridum, Metarhizium anisopliae (Metch.) Sorokin sensu lato (all Ascomycota: Hypocreales); and Entomophaga calopteni (Bessey) Humber and Entomophaga macleodii Humber (unpublished) (Zoopagomycota: Entomophthorales). First reported in this work were M. acridum from an arid zone in the Nearctic region, S. nitens as a host of M. acridum and Entomophaga sp. in Mexico, combined infections by B. bassiana and Entomophaga spp. on melanopline grasshoppers, and new distribution records for E. calopteni in Mexico. Internal sporulation of Beauveria on large melanopline grasshoppers was observed. The impact of these natural enemies should be verified. The Chihuahuan Desert strains of M. acridum should be considered for control of North American grasshopper pests.