Fungal pathogens as classical biological control agents against arthropods

Abstract

Fungal entomopathogens have been used more frequently than other types of pathogens for classical biological control. Among 136 programs using different groups of arthropod pathogens, 49.3% have introduced fungal pathogens (including both the traditional fungi and microsporidia). The most commonly introduced species was Metarhizium anisopliae (Metschnikoff) Sorokin, with 13 introductions, followed by Entomophaga maimaiga Humber, Shimazu & Soper, which was released seven times. The majority of introduction programs have focused on controlling invasive species of insects or mites (70.7%) rather than on native hosts (29.4%). Almost half of the introductions of traditional fungi targeted species of Hemiptera and 75% of the microsporidia introduced have been introduced against lepidopteran species. The United States was the country where most introductions of fungi took place (n = 24). From 1993 to 2007, no arthropod pathogens were released in the US due to the rigorous regulatory structure, but in 2008 two species of microsporidia were introduced against the gypsy moth, Lymantria dispar (L.). Establishment of entomopathogenic fungi in programs introducing traditional fungi was 32.1% and establishment was 50.0% for programs introducing microsporidia. In some programs, releases have resulted in permanent successful establishment with no non-target effects. In summary, classical biological control using fungal entomopathogens can provide a successful and environmentally friendly avenue for controlling arthropod pests, including the increasing numbers of invasive non-native species.

Conservation biological control using fungal entomopathogens

“…Conservation biological control 193 For example, B. bassiana is ubiquitous in soil but has recently been shown also to be common in the plant canopy, active against plant pathogens and even systemically active within plants, providing further opportunities for exploitation (Meyling and Eilenberg 2007;Pell 2007;Vega et al 2009;Ownley et al 2009). These aspects of their ecology would certainly improve the opportunities for exploitation in conservation biological control but should also underpin their use in other strategies Jackson et al 2009;Jaronski 2009;Hajek and Delalibera 2009;Baverstock et al 2009b). It is certainly likely that if conservation approaches were used in conjunction with augmentation that the effectiveness of the augmentation strategy would be improved.…”

Ecological factors in the inundative use of fungal entomopathogens

“…Classical biological control involves introducing a novel fungus for permanent establishment and long term pest control. This subject is discussed by Hajek and Delalibera (2009). Inoculative biological control has the expectation that the agent will multiply, spread, and provide extended control of an insect pest, but only for a finite period.…”

Challenges in modelling complexity of fungal entomopathogens in semi-natural populations of insects

“…There has been considerable research focus on their potential as microbial control agents (e.g. Goettel et al 2005Goettel et al , 2008Pell 2007;Vega et al 2009;Hajek and Delalibera 2009;Jaronski 2009;Pell et al 2009). Indeed, they are considered to have been instrumental in the advent of modern microbial control (Steinhaus 1949;Burges and Hussey 1971;Krassilstchik 1888;Vega 2008) and our knowledge of fungal ecology in crop ecosystems has largely been driven by applied studies assessing their potential for microbial control.…”