Master Gardener’s Insights: Tackling Japanese Beetles In St. Cloud

THIS INVASIVE SPECIES HAS MADE ITS WAY TO ST CLOUD

Master Gardener Bill Cook joined me yesterday to talk about gardening on WJON and informed me that a pest we have all heard about has made its way to the St. Cloud area. He has found them in his gardens. This hungry little bug will eat your garden goods before you do if you aren't prepared.

HOW DID THEY GET HERE?

The insect was first found here in Minnesota back in 1968, but by 2001 the number of Japanese Beetles had increased. The Minnesota Department of Agriculture trapped over a million beetles.

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JAPANESE BEETLE SUPERPOWER

According to the University of Minnesota Extension, the beetles are most commonly found in the Twin Cities, but they are moving. The beetles are pretty amazing! They have the ability to emit an air-borne chemical that attracts more beetles to the area. "Hey, Guys....the good stuff is over there!" Yikes. Pretty impressive bug.

NOT PICKY EATERS

Unfortunately, Japanese Beetles aren't picky about what they eat. They feed on the leaves, flowers and fruit over more than 300 different kinds of plants, including many of the things we plant in our flower and vegetable gardens yearly.

The beetles feed on the tissue between the major veins of leaves and leave them with a 'lace-like' appearance. The good news is that their damage usually affects just the appearance of the plant. Most mature trees and shrubs can handle the feedings without long term consequences; but young plants can definitely be killed by the feeding of the Japanese Beetle.

Some of their favorite things to eat include:

• Rose bushes
• Grape vines
• Apple Trees
• Crabapple Trees
• Cherry Trees
• Plum Trees
• Raspberries
• Hollyhock
• Marigold
• Corn Silks
• Soybeans
• Birch Trees
• Elm Trees

GRUBS

Japanese Beetle Grubs can also damage grass roots. You'll know that you have a severe grub problem when you see dead patches of grass start to develop in your yard. They can be rolled back like a carpet due to the lack of roots.

HOW TO SLOW THEM DOWN

Regularly harvesting during the months of July and August can keep them from feeding on the edible parts of your plants.

Physically removing the beetles can be the best and most effective way to save your gardens and fruit and veggies from this pretty pest. Simply handpick them or knock them into a bucket of soapy water to kill them. You should check your platns daily and remove the beetles that you see to stop the damage.

DO NOT TRAP THEM

Trapping them is the worst thing you can do as it will just attract more Japanese Beetles to your area. Even though the traps collect lots of beetles it typically just results in more damage to gardens near the trap.