Marshfield Monarchs Offer Tips to Combat Japanese Beetles

Thursday, June 1st, 2023 -- 1:00 PM

It’s almost Japanese beetle season in Central Wisconsin.

In anticipation, Marshfield Monarchs is sharing some useful information on how to combat these harmful bugs without hurting local pollinators. Most important to know: Traps do more harm than good.

“These awful little creatures can wreak havoc on people’s gardens, landscaping, trees and yes, milkweed. As if our poor monarchs don’t already have enough to deal with this year, now they have to fight these devils,” Marshfield Monarchs founder Melissa Gwiazda shared.

“I did my homework on Japanese beetles last year because I wanted to know how to eradicate them without harming or poisoning other insects, especially the monarchs.” She said that many people put out beetle bag traps with good intentions, but these actually cause more harm than good.

“Most people will put out ‘Beetle Bags’ thinking that this will help keep them away from their plants and is a good way to trap and kill the ones in their yard which is further than the truth!! In FACT, the beetle bags will only attract MORE beetles to their yard,” she said.

“What most people don’t know is that the beetle bags were designed ONLY for people in rural areas who grow crops or have orchards. The bags are meant to be placed far enough away from the crops so that the beetles are lured away.”

One single bag can attract a beetle through the pheromones used in the bag from up to 4 MILES away, so essentially using just one bag in a private yard in town can attract 4 miles worth of beetles…bringing even more not only to one property but bringing more into surrounding neighbor’s properties as well.

“We definitely do NOT recommend using beetle bags if you live in town. You are actually doing more harm than good,” she said. “What we suggest is getting some Neem oil. Neem oil when diluted with water and sprayed on your plants will detour the beetles from eating and destroying your plants by up to 90%! This spray does not harm other insects although we do not recommend spraying it on your milkweed.”

She said another product to use to help eradicate the beetles is “Milky Spore”. Milky Spore is a powder that can be spread on a lawn in spring or fall (before a rainfall is best) that will kill the beetle grubs.

It’s also important to note that while the bags may seem like they are trapping the beetles, they are actually attracting MORE beetles to your yard. This means that next year, the beetle problem will increase as those beetles reproduce prior to being trapped.

For more information, visit Marshfield Monarchs on Facebook: https://www.facebook.com/MarshfieldMonarchs.

Feel free to contact us with questions and/or comments.