A study of host specificity in the entomopathogenic fungusBeauveria bassiana(Hypocreales, Clavicipitaceae)

Abstract

Beauveria bassiana (Balsamo Á Crivelli) Vuillemin based mycoinsecticides are used against agricultural, veterinary and medical insect pests. The fungus has a very diverse and extensive host range. Variation in virulence among isolates of B. bassiana to different insect species has been abundantly documented. Given the effect of multiple factors on virulence, it is not certain whether the observed difference in virulence can be labelled as host specificity. Environmental conditions and susceptibility of the insect population are two main factors that affect successful fungal infection. Keeping the environmental factors constant, if virulence of an isolate to different insect species and different populations within an insect species is compared, the scale of difference between the two responses can be estimated. If differences in virulence of an isolate to different insect species are greater than the difference in virulence to different insect populations within an insect species, then, the isolate can be considered as exhibiting specific preference to those insect species towards which it exhibits high virulence. To examine this feature, a worldwide sample of B. bassiana was bioassayed on nine insect species and two different populations within two insect species. Laboratory bioassays were done on: Bombyx mori (Lepidoptera), Spodoptera litura (Lepidoptera), Chilo partellus (Lepidoptera), Helicoverpa armigera (Lepidoptera), Epilachna vigintioctopunctata (Coleoptera), Mylabris pustulata (Coleoptera), Aphis craccivora (Homoptera), Maconellicoccus hirsutus (Hemiptera) and Oecophylla smaragdina (Hymenoptera). The range of variation in virulence of a B. bassiana isolate to different insect species was not more than that observed with different populations within a single insect species. B. bassiana is thus a generalist with no strict host preference. B. bassiana based biopesticide can be used as a broad spectrum insecticide against a myriad of insect pests.

Natural enemies of the Coccinellidae: Parasites, pathogens, and parasitoids

“…Beauveria bassiana (Balsamo) (Ascomycota: Hypocreales: Clavicipitaceae) is a generalist pathogen most often reported infecting phytophagous (Uma Devi et al, 2008) and entomophagous (Roy and Cottrell, 2008) coccinellids. Larvae of the phytophagous Epilachna vigintioctopunctata F. and Henosepilachna vigintioctomaculata (Motschulsky) are susceptible to B. bassiana (Kuznetsov, 1997;Uma Devi et al, 2008). Even though H. vigintioctomaculata field populations were decimated by fungal pathogens during the 1960s, only about 6% of H. vigintioctomaculata were found infected in the field at two subsequent points in time (Kuznetsov, 1997).…”

VOLCANIC MATERIALS AS CARRIERS FOR THE FORMULATION OF MYCOINSECTICIDES USING THE FUNGUS Beauveria bassiana

“…From a biological point of view, this fungus can infect many pest insect species, inducing high mortality rates (Uma Devi et al, 2008). From the commercial perspective, spore mass production has been successfully achieved, and there are many companies offering products based on B. bassiana (Seema et al, 2013).…”

Wood ants protect their brood with tree resin

“…In the laboratory, we removed the resin already present in the nest material. We split the samples from each field nest into four experimental nests, assigned to four treatments, in full factorial design: presence or absence of pupae and presence or absence of B. bassiana, a virulent generalist fungal entomopathogen (Uma Devi, Padmavathi, Uma Maheswara Rao, Khan, & Mohan, 2008). Beauveria bassiana has been reported to successfully infect and kill adult ant workers (Purcell, Brütsch, & Chapuisat, 2012;Reber & Chapuisat, 2012a) and brood (Broome, Sikorowski, & Norment, 1976;Patterson, Briano, Wildey, & Robinson, 1993).…”