How to control earwigs and Japanese beetles in your garden

Pests like earwigs and Japanese beetles are a natural part of a garden, but they can become a problem if they get out of control. Read on to learn more about the role of pests in your garden and what can be done about them.

Beth Smerek, a bedding plant specialist at a Boulder, Colorado, nursery, advises that most insects are beneficial or neutral to your plants, and when beneficial insects (such as those that eat pests) are killed, a dependency on chemicals is created. Before killing everything that moves the minute you notice some holes in the leaves, bring an affected leaf or picture of the problem to a reputable garden centre and find out what is wrong. Then you can choose the treatment that will attack that problem specifically.

Smerek adds that it's safer to use chemical treatments on indoor plants, because the indoor environment is completely artificial and contained, and thus the chemicals won't affect creatures other than the target pests.

Those cheerful yellow and orange flowers are often sold to gardeners with the promise that they'll deter pests from attacking vegetables, but marigolds' effectiveness against pests is limited. They only work well as a defense against nematodes in the soil, says veteran gardener Beth Smerek. Still, the blossoms are pretty in the garden, so go ahead and plant them. They can't hurt!

Frustrate the insecticide salesmen with this no-poison, low-tech solution to earwig control.

• In the evening, roll up sheets of wet newspaper and lay them around the garden. At sunrise, earwigs will crawl inside the wet pages to take shelter.
• Collect the papers before they dry out, bugs and all. Don't throw the newspapers into your trash cans, or the earwigs will soon escape and make their way back to the garden.
• Either burn the papers and bugs, shake the earwigs into a toilet or sink and flush them down the drain, or tie up the papers and bugs tightly inside a plastic bag — with absolutely no openings — and put them in the garbage can.

If you have a problem with grubs eating your grass and plants, chances are you also have a problem with Japanese beetles, because the grubs are most likely the larvae of the beetles. You can solve both problems by just killing the grubs so that they don't develop into beetles. Although gardening outlets are quick to sell fast-acting toxic chemicals to kill the grubs (and a lot of other less harmful insects), there is a perfectly fine natural remedy that will get rid of them for years to come. Called milky spore, it causes the grubs to contract a disease that kills them. Other beneficial organisms are not harmed.

The only problem is that you have to be patient. Milky spore is slow acting — after you spread the granules on your lawn, it can take a year or more for the spore to become established in your soil. But once the spore is established, it keeps working for a decade or more. There are reports of a single treatment lasting 40 years. Milky spore is not cheap; a single can of the granules runs about $40, but considering the length of the benefit, it's a real bargain.