Windsor horticulturalist gives tips on managing Japanese Beetles

Gardeners in SouthernOntario are noticing more Japanese Beetles popping up this summer, particularly in Windsor-Essex and Niagara regions.

A mild winter, warm weather and areas with light, sandy soils attract the beetles and Windsor-Essex is becoming a hot spot.

"The white grubs you find in your lawn, those will be Japanese Beetles," said Sandy MacDonald, a horticulturalist and professor at St. Clair College.

What is a Japanese Beetle?

The Japanese Beetle is the adult form of a white grub. The grub lives underground during the winter months and re-emerges in soil in the summer months. Many people will discover the beetles on leaves or flowers.

An active beetle will eat and destroy vegetation, including turfand plants. According to MacDonald, the Japanese beetle will eat over 300species of plants.

"They love roses, they love fruit trees, and they go on geraniums," said MacDonald. "People have seen them feeding on poison ivy, even cannabis," said MacDonald.

"They will eat away at the tissue and defecate on it and make a mess of the flowers as well and spoil the flowers very quickly."

Why are there so many?

The grubs survive underground when the winter is mild. This past winter was considered a mild one and temperatures have been increasingly warmer during the spring and summer, therefore the adult beetles are appearing in larger numbers.

"Five, six, seven years ago we had a couple really cold winters in a row, we had very few of them in gardens. They were actually hibernating down in the ground but they didn't get low enough to avoid being frozen with extremely cold weather," said MacDonald.

How do you deal with them?

Managing the beetles, particularly if there is an infestation, can be an extensive process.

Due to provincial pesticide controls, the use of pesticides can be limited, according to MacDonald.

He suggests setting up a trap, but warns it can be considered controversial.

"The trap actually draws them in from the neighbours yard as well. So the recommendation there is to put it in the back of your yard away from those plants that are valuable," said MacDonald.

The safest method, according to MacDonald, is picking up each individual beetle and dropping it in a bucket of soapy water.

"You can get hundreds and hundreds of them that way," said MacDonald.

MacDonald recommends treating the lawns for grubs earlier in the season to prevent more appearances later on.