Beauveria bassiana

Beauveria bassiana kills insects without the elaborate behavioral manipulation of Ophiocordyceps or Massospora. This generalist pathogen infects over 700 insect species by penetrating their exoskeletons, growing inside their bodies, and producing toxins that kill them. The dead insects turn white as fungal spores cover their surfaces—hence 'white muscardine.' The strategy is brute force rather than sophisticated manipulation: infect, kill, sporulate, spread.

B. bassiana's broad host range made it attractive for biological pest control. Commercial formulations are used against agricultural pests including aphids, whiteflies, and beetles. Unlike Ophiocordyceps's narrow host specificity, Beauveria's generalism enables single products to address multiple pest species. The trade-off is less efficiency against any single target—specialists often outcompete generalists when both are present—but greater market flexibility.

The fungus produces several bioactive compounds including beauvericin and bassianolide, which contribute to pathogenicity. These compounds have attracted pharmaceutical interest for potential antimicrobial, anticancer, and immunosuppressive applications. Understanding how Beauveria kills insects has yielded molecules with human medical relevance. The relationship between ecological role (insect pathogen), applied use (biocontrol agent), and drug discovery (bioactive compound source) illustrates how single organisms can serve multiple human purposes.