A Comparison of the Activity of Soil Fungal Isolates Against Three Insect Pests

Abstract

Entomopathogenic fungi (e.f.) are important agents of biological control of insects. Two aspects, among others, are important for the use of e.f. against insect pests: the logistics of e.f. strain acquisition, and the activity of individual strains against multiple insects. Soil is the natural reservoir for many e.f., but only few strains used against insect pests originate from soil; most have been isolated from insects. Also, there are few reports that simultaneously compare the activity of individual strains of e.f. (of insect or soil origin) against more than one insect species. This is important for the deployment of e.f. in agroecosystems, where simultaneous control of several insect pests is very often desirable. In this work we determined and compared the simultaneous activity of local strains of e.f. (isolated from soil or insects at Saltillo, Mexico) against important regional pests: fall armyworm, Spodoptera frugiperda, greenhouse whitefly, Trialeurodes vaporariorum, and potato psyllid, Bactericera cockerelli. Against all three insects, one Beauveria bassiana strain from soil was as active as or more active than other B. bassiana and Metarhizium anisopliae strains from insect or soil origin. In some localities, native individual strains of e.f. from soil might have good activity against multiple local insect pests. We recommend the isolation and testing of local soil strains of e.f. for use in local biocontrol projects.