Gardening column: Beetle grubs take long winter nap

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Gardens are living things and, when we think all is quiet and asleep during the winter months, they are really hotbeds of activity.

Perennials, shrubs and trees are expending energy growing strong root systems that lie below the frozen ground and snow-covered lawns. Our spring bulb plants are developing strong roots so that at the first sign of spring, they can come forth and delight us with their beauty.

At the same time these good things are going on, not-so-pleasant pests are working diligently to develop and be ready to continue their life cycle in the next season. One particular pest is the Japanese beetle.

In the soil under the beetle's favorite edibles such as clematis, roses, hibiscus, linden and Japanese maple trees, they will lay their eggs.. Those will hatch and develop into grubs, a white worm that curls itself into a “C” shape. This grub feeds on the roots of grass and other plants and continues to grow until it is about 1 inch long.

As it develops over the summer, it has a voracious appetite and will kill large patches in our lawns while burrowing deeper and deeper in the soil until it has buried itself six to 18 inches in the ground.

When autumn comes and the ground cools, the grubs go to sleep, and in late spring they wake up and begin their journey toward the surface.

At one to three inches from the surface of the soil, they form into a pupa — which in a few weeks hatches and the adult beetle makes its way to the surface, where it looks for a mate and feeds on the new leaves and blossoms of its favorite plants — and the cycle begins again.

To tell whether you have grubs, pull on the dead grass, and if it comes up with no resistance (unless you've been treating weeds in your lawn with Roundup), you can be 99 percent sure you have grubs.

You can rid yourself of this pest, but you need to know when it is vulnerable and take the necessary steps to stop it. Here are a few tips that should help:

•Spring and early fall are the best times to treat for grubs. They are close to the surface then.

•If you discover the beetles munching on your plants, plan to attack them in the early morning when they are sluggish after cool night temperatures. Prepare a bucket of warm soapy water and shake them off the plant into the water or squish them and drop them in the water.

•If you would rather not do that, you can treat the plant with a spray or granular chemical that contains imidacloprid. This chemical is systemic and is absorbed by the grass or ornamental plant, which provides more long-term control. You can use Sevin, but this chemical lays on the surface of the plant and will need to be reapplied more often.

•Many people believe traps are the way to go, but if you use one, you need to place the trap far away from their favorite plants because it works as an attractant rather than a deterrent.

•Over time you may want to rid your garden of Japanese beetles by replacing their favorite plants with those they don't care for. Some of those safe plants are coral bells, coreopsis, delphinium, foxglove, hosta, impatiens, lantana and nasturtium.