Denny Bruck is an entomologist (a scientist who studies insects) in the Agricultural Research Service's Horticultural Crops Research Unit at Corvallis, Oregon. He found an entomopathogenic fungus that is very bad for weevils. In fact, it can kill them. Using this substance could help us protect our plants from weevils.
Why would a weevil eat a fungus if it's unhealthy? The answer is that they don't. They'll eat something that's good for them––like roots––that brings them close to the fungal spores. Then the spores penetrate their cuticles and cause an infection. They think they're eating something tasty and nutritious, but it's actually not good for them at all.