Variation in physiological host range in three strains of two species of the entomopathogenic fungus Beauveria

Abstract

Knowledge of the host range of a biocontrol agent (BCA) is fundamental. Host range determines the BCA’s economic potential, as well as the possible risk for non-target organisms. Entomopathogenic fungal strains belonging to the genus Beauveria are widely used as BCA, but our knowledge of their physiological host range is only partial. The aim of this study was to improve our understanding of the physiological host range of three Beauveria strains belonging to two species, B. hoplocheli and B. bassiana. We performed laboratory mortality bioassays to assess their pathogenicity and virulence against nine insect pests, belonging to three orders: Lepidoptera, Coleoptera and Diptera. Mortality rate, mean survival time and mycosis rate were used to estimate virulence. Pathogenicity was assessed as the capacity to cause a disease and induce mortality. Virulence was assessed as the severity of the disease based on mortality rate, mean survival time and mycosis rate. The results of this study revealed significant differences in the physiological host range of the three Beauveria strains tested. The three strains were pathogenic to all Diptera and Lepidoptera species tested. In the case of the Coleoptera, only the B. hoplocheli strain was pathogenic to the white grub Hoplochelus marginalis and only the B. bassiana strains were pathogenic to Alphitobius diaperinus. The B. hoplocheli strain was less virulent on Lepidoptera and Diptera than the two B. bassiana strains. The latter both exhibited very similar virulence patterns. The fact that B. hoplocheli and B. bassiana strains have different host ranges means that they can be used as BCA to target different pests. Impacts on non-target insects across multiple orders cannot be ruled out in the absence of ecological host range studies.

Efficacy of soil-borne entomopathogenic fungi against subterranean termite, Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae)

“…According to Altre et al (1999), different isolates of same species do not have equal virulence potential to the same insect pest. The differences in pathogenicity to an insect host with the same fungal species was also reported by Rohrlich et al (2018). Aspergillus auricomus and A. caelatus did not show a promising insecticidal potential to control C. curvignathus in the present study.…”

Isolation of Beauveria bassiana Pr-11 from Andean orthopterans and its effectiveness against Chagas disease vectors in Peru

“…Strong variations in the virulence of B. bassiana strains have been observed (Luz et al, 2004) and these have been associated to several aspects of the hostpathogen interaction (Rohrlich et al, 2018). The mode of action of this pathogen consists on a first adhesion step to the insect cuticle and later hyphal penetration and proliferation of the cuticle of the infected host (Gabarty et al, 2014).…”

POTENSI FILTRAT TEH HITAM SEBAGAI PELINDUNG SINAR UV TERHADAP S/NPV JTM 97 C DALAM MENGENDALIKAN Helicoverpa armigera / Potency of Black Tea Filtrate as UV Protectant to S/NPV JTM 97 C in Controlling Helicoverpa armigera

“…Warna larva H. armigera yang terinfeksi S/NPV JTM 97 C terlihat mengkilap dan berwarna abu-abu kemerahan, seperti gejala kematian pada larva Crocidolomia binotalis yang terinfeksi S/NPV JTM 97 C (Zulfahmi et al 2015). Persentase kematian larva H. armigera oleh S/NPV JTM 97 C dengan bahan pelindung filtrat teh hitam paling tinggi mencapai 47,5%, masih di bawah minimal 50% menurut standar nilai mortalitas (Rohrlich et al 2018). Hal ini berbeda dengan hasil penelitian Sukirno et al (2018), bahwa perlakuan ekstrak teh hijau sebagai bahan pelindung Spodoptera littoralis Nucleopolyhedrovirus (SpliMNPV) mampu menyebabkan kematian S. litura hingga 90%.…”