Susceptibility of larvae and adults ofMonochamus galloprovincialisto entomopathogenic fungi under controlled conditions

Abstract

Six entomopathogenic fungal isolates were tested under controlled conditions, as biological control agents against Monochamus galloprovincialis (Coleoptera: Cerambycidae) (Olivier), the vector of the pine wood nematode Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) (Steiner and Buhrer). The fungi Beauveria bassiana (Bals.-Criv.) Vuill, Metarhizium anisopliae (Metchnikoff) Sorokin, Metarhizium sp. and Fusarium sp. were tested against larvae and adults of the insect, by comparing two exposure techniques: continuous contact and spraying. Regarding the larvae, only Fusarium sp. and Metarhizium sp. killed more than 40% of the individuals, while B. bassiana and M. anisopliae were found to kill 50% of the adults (LT 50 ) within five days. Exposure to B. bassiana reduced adult longevity by 19 days, when compared to untreated beetles, and had a direct efficacy of 46%. Continuous contact with the fungi proved to be more effective than spraying. A larval disinfection protocol was developed to eliminate other fungal isolates from the wood-collected tested individuals. The implications of the results and possible applications of selected strains as bio-control agents against M. galloprovincialis are discussed.

Nematicidal effect of Beauveria species and the mycotoxin beauvericin against pinewood nematode Bursaphelenchus xylophilus

“…In terms of insect vector control, several strategies have been developed to reduce M. galloprovincialis populations such as a trapping method combining pheromone and kairomones (Álvarez-Baz et al, 2016; Galloprotect 2D R ), the use of entomopathogenic fungi (Naves et al, 2008;Álvarez-Baz et al, 2015;Petersen-Silva et al, 2015) and the development of an auto-infection device based on the combined use of the attractant and the entomopathogenic fungi (Sacristán-Velasco et al, 2018). To date, only the use of traps with attractants has been implemented more widely, but successful field trials have been performed combining this system with the auto-infection device and powdered formulations of an entomopathogenic fungus (Martín-García, Unpublished data).…”

“…However, little attention has been paid to potential nematicidal effects of the genus Beauveria spp. on PWN, despite significant mortality effect on other nematodes species being thoroughly documented (Youssef et al, 2020;Ye et al, 2021;Karabörklü et al, 2022) and its entomopathogenic effect on M. galloprovincialis is well known (Naves et al, 2008;Álvarez-Baz et al, 2015;Petersen-Silva et al, 2015). Maehara et al (2007) proved the reduction of PWN transmission from vectors due to Beauveria bassiana was possible; however, this potential control method has not been examined in depth.…”