Susceptibility of Phyllophaga polyphylla and Anomala cincta larvae to Beauveria bassiana and Metarhizium anisopliae isolates, and the interaction with soil properties

Abstract

The white grub species Phyllophaga polyphylla and Anomala cincta (Coleoptera: Melolonthidae) are economically important species that affect many crops in Mexico. A series of experiments to study the pathogenic interaction between isolates of Beauveria bassiana and Metarhizium anisopliae and these two insect species were undertaken. First, the susceptibility of third instar P. polyphylla larvae to each of seven isolates representing both species of fungus was evaluated by dipping the insects in 1 9 10 8 conidia ml -1 suspensions. A second study examined the differences in the susceptibility of P. polyphylla and A. cincta larvae to two selected isolates for each of the fungal species. Finally, the susceptibility of A. cincta larvae to one M. anisopliae isolate when incubated in soil collected from four different sites was assessed. No significant differences in proportion of infection of P. polyphylla larvae were observed amongst the fungal isolates tested and mortality due to fungal infection was never greater than 20% after 36 days incubation. Anomala cincta larvae were more susceptible than P. polyphylla larvae, with greater than 90% infection when inoculated with isolates of M. anisopliae whereas mortalities of only 20% where achieved against P. polyphylla larvae. The soil type in which A. cincta were incubated following inoculation with M. anisopliae affected their susceptibility to infection. The results demonstrated that there is a complex interaction amongst entomopathogenic fungi, white grub larvae and soil properties, and points to the need of further investigation of this system in order to optimize the efficacy of entomopathogenic fungi against these insect species.

Potential of two entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae (Coleoptera: Scarabaeidae), as biological control agents against the June beetle

“…This is consistent with the results reported here. However, higher virulence of M. anisopliae compared with B. bassiana isolates against Anomala cincta (Say) (Coleoptera: Melolonthidae) was found by Guzmán-Franco et al. (2012) .…”

Metarhizium pingshaense applied as a seed treatment induces fungal infection in larvae of the white grub Anomala cincta

“…Infectivity of M. pingshaense to A. cincta when applied as a seed treatment or by direct inoculation Third instar A. cincta larvae were collected from maize crops near San Lorenzo, Guanajuato, Mexico (August-November 2012), transported to the laboratory and identified as described by Guzmán-Franco et al (2012). Conidial suspensions of M. pingshaense isolate MGC02 (from an infected white grub (Carrillo-Benítez et al, 2013)) were prepared as described by Guzmán-Franco et al (2012). We used this isolate because the susceptibility of A. cincta larvae to this isolate, when inoculated directly onto the larvae, had been previously evaluated .…”

A novel method to optimize culture conditions for biomass and sporulation of the nematophagous fungus Metarhizium anisopliae SQZ-1-21 and the entomopathogenic fungus Metarhizium anisopliae RS-4-1

“…Metarhizium spp. plays an important role in controlling the number of pests in the soil (Bruck, 2005;Scheepmaker and Butt, 2010;Guzmán-Franco et al, 2012). However, when applied to fields, the fungi do not typically display satisfactory biocontrol efficiency.…”