An insect from Europe is showing up in Michigan. It might help control an invasive plant. Garlic mustard chokes out native plants. The most common way of controlling garlic mustard is pulling it up by hand.
The plant, which tastes like garlic, was once popular in vegetable gardens. But it escaped into the wild.
It comes up in early spring and grows a little faster than native plants. So, it spreads and crowds out native plants along roads, streams, and in forests. Since there are no native predators, it doesn’t support insects, which in turn support birds and so on up the food web. So it’s of no help to the Michigan ecosystem.
Recently a tiny bug from Europe that feeds on garlic mustard has been showing up in some areas of Michigan. It’s unknown how it got here. It was first spotted in Ohio by biologist Rebecah Troutman in 2021.
The European garlic mustard aphid (Lipaphis alliarae) might be a natural deterrent to the spread of garlic mustard in Michigan and elsewhere. But there are concerns.
“Bio control has a spotted history, right? Where sometimes we let out a species that we think is going to help and then it ends up doing more damage. Since this isn't a species that we introduced on purpose, at this point, we need to gather a lot more information,” said Katie Grzesiak, terrestrial invasive species coordinator for the Michigan Department of Natural Resources.
It’s too early to be certain, but it seems the aphid just wants to munch on garlic mustard.
“We don't have a lot of native plants that are very closely related to garlic mustard. And a lot of times these little insects are really, really closely tied to their specific food sources,” Grzesiak said.
