Evaluation ofMetarhizium brunneumF52 (Hypocreales: Clavicipitaceae) for Control of Japanese Beetle Larvae in Turfgrass

Abstract

Experimental and commercial preparations of Metarhizium brunneum (Petch) strain F52 were evaluated for control of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarbaeidae), larvae (white grubs) in the laboratory and under field conditions. Experimental preparations consisted of granule and liquid formulations made using in vitro produced microsclerotia, which are intended to produce infective conidial spores after application. These formulations were compared against commercial insecticides (imidacloprid and trichlorfon), and commercial formulations of M. brunneum F52 (Met 52) containing only conidia. Field-collected grubs were susceptible to infection in a dosage-dependent relationship when exposed to potting soil treated with experimental microsclerotia granules in the laboratory. The LC 50 for field-collected larvae was 14.2 mg of granules per cup ($15 g granules/m 2 ). Field plots treated with experimental and commercial formulations of M. brunneum F52 after 10 September (targeting second and third instar grubs) had significantly lower grub densities compared with untreated plots, providing 38.6-69.2% control, which sometimes equaled levels of control with chemical insecticides. Fungal treatments made prior to 21 August provided 14.3-69.3% control, although grub densities resulting from these treatments were often not significantly lower than those in untreated control plots. By comparison, chemical insecticide treatments provide 68-100% grub control, often providing better control when applied earlier in the season. In conclusion, P. japonica larvae are susceptible to infection by M. brunneum, and grub densities were reduced most consistently by fall applications targeting later instars.

Mechanisms of Environmental Stress Tolerance in Turfgrass

“…For example, tea seed pellets, the byproduct of tea oil, expels earthworms in turf [206]. Metarhizium brunneum (Petch) is beneficial for controlling the development of the Japanese beetle (Popillia japonica Newman) in turfgrass [207]. These observations could provide useful methods for earthworm and beetle management in turfgrass.…”

The entomopathogenic fungus Beauveria bassiana produces microsclerotia‐like pellets mediated by oxidative stress and peroxisome biogenesis

“…Microsclerotia are tolerant to desiccation and able to produce infective conidia under nutritionally poor conditions, thereby making these structures promising stages to develop as formulated propagules for use as mycoinsecticides for soil or aquatic applications. The microsclerotia propagules from entomopathogenic fungi are usually obtained by liquid culture fermentation (Jaronski and Jackson, 2008;Mascarin et al, 2014;Behle et al, 2015;Song et al, 2016;Jackson and Payne, 2016). By transcriptomic approaches, some authors proposed that oxidative stress is linked with microsclerotial development in which the iron ion (Fe +2 ) plays an important role during its formation (Georgiou et al, 2006;Song et al, 2013).…”

Production and Stabilization of Mycoherbicides

“…The field efficacy of solid and liquid formulations of microslecrotia Metarhizium brunneum F52 was lower or comparable with its conidial preparations. However, microsclerotia of the fungus can be applied with a harsh hydro-mulch technique [59].…”