UW–Madison Smart Restart: For information about fall semester instruction and campus operations, please visit For COVID-19 news updates, see

During this time, please contact us at

Invasive insect hits berry crops – Audio

Christelle Guedot, Extension Entomologist
Department of Entomology
UW-Madison College of Agricultural and Life Sciences

3:06 – Total Time

0:20 – New invasive insect hits berry crops
0:40 – Affected crops
1:00 – How it hurts berry crops
1:24 – Statewide problem
1:43 – Insect with teeth
2:30 – Where to get information
2:56 – Lead out

Sevie Kenyon: A new bug in the berries. We’re visiting today with Christelle Guedot, Department of Entomology, University of Wisconsin Extension and the College of Agricultural and Life Sciences, Madison, now celebrating 125 years, and I’m Sevie Kenyon. Christelle, an invasive insect has moved into our fruit, berry crops, can you tell us what that is?

Christelle Guedot: This is a spotted-wing drosophila, it looks very much like a fly you would have in your kitchen and it’s an invasive species. It was first detected in 2010 and has been a problem since 2012.

Sevie Kenyon: What crops does it affect?

Christelle Guedot: It’s a pest of small fruit crops so it likes smaller, soft-skin fruit such as raspberries, blueberries, blackberry, grape and it has been reported in peach. So those kind of small fruit.

Sevie Kenyon: What will people noticed if spotted wing dropsophila move in on their crops?

Christelle Guedot: What you’ll notice is the larva in the fruit. So small, white larva that don’t have any legs, can’t see a head. When they’re fully mature they’re about 3mm long, that’s very tiny. But when it’s on a raspberry, it’s really big when it’s chewing on your raspberry.

Sevie Kenyon: And Christelle, how widely spread is this in the state of Wisconsin?

Christelle Guedot: Pretty much everywhere where you’ll have a small fruit. So we don’t have an exact location we’ve been monitoring but only where we can monitor where we have collaborators that can trap for us but pretty much everywhere we trap we get spotted-wing drosophila.

Sevie Kenyon: Christelle, can you describe the life cycle of this spotted-wing drosophila?

Christelle Guedot: It’s very interesting when you talk about the life cycle because the basic life cycle you have the female lay eggs under the skin of the fruit and this fly is very unique compared to other drosophila. When you have drosophila in your kitchen they go to the fruit that’s already rotting or cracked. These flies, the females, have an egg laying apparatus that has teeth on it, and two rows of teeth, very nice sharp teeth that allows them to cut the skin of the fruit and then they can lay their eggs under the skin of the fruit so they don’t need to wait for that fruit to be over-ripe or cracked. They can attack ripening and ripe fruit and that’s what makes them so unique.

Sevie Kenyon: Christelle, is there a place people can get more information about spotted-wing drosophila?

Christelle Guedot: Yes so we have a website actually that we put together specifically for this fly for people to get information. There’s information about their biology, their management, how to deal with it, how to trap for them, monitor for them. All of that information and if you pretty much Google SWD Wisconsin, that website will show up or if you type “spotted-wing drosophila Wisconsin” that website will show up.

Sevie Kenyon: We’ve been visiting with Christelle Guedot, Department of Entomology, University of Wisconsin Extension and the College of Agricultural and Life Sciences Madison, Wisconsin now celebrating 125 years and I’m Sevie Kenyon.