Distribution, Abundance and Diversity of Fungal Entomopathogens: Foundations for Conservation Biological Control

Summary

Conservation biological control (CBC) is a pest management strategy in which farming management practices are adopted to enhance the living conditions for specific natural enemies of pests with the specific objective to suppress pest populations. Research in CBC strategies have mostly focused on provisioning of good living conditions for arthropod predators and parasitoids, usually ignoring entomopathogens as regulators of pest populations.
Fungal entomopathogens are widespread in agro-ecosystems and infect a range of arthropod pests, and these fungi should therefore also be included in CBC. Knowledge of the ecology of indigenous populations of fungal entomopathogens is a prerequisite for the evaluation of their contributions to pest control and for predicting consequences of agricultural practices.
The anamorphic entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae (Ascomycota: Hypocreales) are among the most abundant fungi infecting insects and arachnids in temperate regions. Much focus has been on the development of B. bassiana and M. anisopliae as biological control agents (for inundation and inoculation biological control) to be applied in agriculture and forestry. However, few studies have focused on the fundamental ecology of these fungi in terrestrial ecosystems, including agro-ecosystems.
I will present recent results providing several new insights into the abundance, distribution and diversity of B. bassiana in agricultural fields and their surrounding habitats and discuss these in relation to CBC. Systematic uses of traditional isolation techniques show complex distributions of B. bassiana in both soil and aboveground environments. Applications of molecular markers demonstrate remarkable diverse structures of Beauveria communities as well as novel insights into the interpretation of host range. Numerous interactions among fungal entomopathogens and their hosts (including both pests and beneficials) potentially affect the impact of the fungi on pest regulation. Novel data on spatio-temporal distribution of B. bassiana and M. anisopliae in above- and belowground environments will also be presented. These results have impact on interpretation of fungal life cycles and which taxa we should expect to infect which hosts and where.