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Entomopathogenic Fungus

A dead blow fly (Lucilia species) killed by an entomopathogenic fungus

A dead blow fly (Lucilia species) killed by an entomopathogenic fungus

SC: I'm Steve Clark with Dr. Art Evans, entomologist, and this is What’s Bugging You. You know, I always like bizarre life cycles stories. Tell me another story, Uncle Art.

AE: Well, I thought today we’d talk about entomopathogenic fungus. Say that ten times fast.

SC: Oh, that’s exciting.

AE: In short, these are fungi that infect insects. You can see them around, and you may not realize what you're looking at. If you peel back some bark, you might see what sort of looks like the outline of an insect, but it's completely covered in mold.

SC: Oh, that’s a casting.

AE: And you’ll see a little casting, but a very fuzzy casting, you may see horn sprouting out in places where the insect doesn't have horns. Sometimes you may find these insects clinging to blades of grass or twigs, and they look very much alive, but then you realize something's not quite right. They look odd, and you inspect them more closely and realize they're covered in fungus, and that is an entomopathogenic fungus.
SC: What color is it?

AE: The ones I've seen can be white or sort of ivory, tan. Some of them are dark brown, more somber colored. What brought this topic to mind is that I had photographed a blow fly right outside my door, and blow flies are brilliant green, and I saw one sitting on a blade of grass and it was very still and as I approached it, it still didn't move, and then I realized something is up. It is surrounded in rings of fuzzy fungus, and apparently this fungus, once it attacks the insect, it will develop inside its body and then it starts pushing its way out through the intersegmental membranes. So you'll see rings of fungus in between the plates of the body, and it'll get puffy, and then it'll produce these fruiting bodies which allow the spores to disperse and eventually infect other insects. Some of these fungi act as parasites. They will change the behavior of the insect and drive them up to the end of a twig or a blade of grass or some open area where they can produce these bodies, and therefore their spores will be more broadly dispersed. But you could imagine there's a lot of interest in entomopathogenic fungi because they can be used as bio control agents. They're already out in the environment, and if they can be targeted towards specific pests, they could be used instead of pesticides to control pest populations.

SC: What would the drawback be?

AE: They would infect all kinds of things. You know that they're not necessarily going to be specific to a certain species of insect, but they tend to attack different orders of insects. In fact, one of these insect attacking fungi has been reported to attack spotted lantern flies, which is a serious pest in select places in the northeast. So this could be good news.
SC: Yeah, so I was just thinking.

AE: Well, stay tuned. We may have more information on that shortly. I've seen all kinds of insects attacked by these fungi - flies, beetles, grasshoppers come to mind, sometimes hoppers.

SC: Is it all the same fungus?

AE: No, there are many different species of fungi that attack insects, and the time when they start really becoming obvious is when the humidity goes up. So keep an eye out for them during the summer. That's when they really go into high gear.

SC: This I'd like to see.

AE: We'll make sure there's a good photograph on the website.

SC: Dr. Art Evans is a Research Associate at the Virginia Museum of Natural History. You’ll find photos, audio, and links to the museum and Art’s Facebook page at ideastations.org/radio/bugs.

Entomologist Dr. Art Evans and WCVE producer Steve Clark discuss insect-killing fungi and note they might be used as biological control agents to combat spotted lanternflies and other insect pests.