In the fungal kingdom, no one is safe from parasites—not even other parasites. A new study from North Carolina State University finds that Ampelomyces, an intracellular fungus that infects the plant disease powdery mildew, is far more common than previously known. By screening museum samples of powdery mildews up to about 150 years old, researchers discovered that not only is Ampelomyces quite common, but many specimens labeled as Ampelomyces are misidentified.