By Henry Homeyer
It’s springtime and insects are hatching, flying, and chewing. Contrary to what you might think, most are not a problem for your garden. There are over a million named insect species, and many – perhaps most – evolved along with flowering plants. They pollinate our crops and do many wonderful things for us.
One of the most hated insects is the Japanese beetle. As the name suggests, these beetles are originally from Japan and were first observed in New Jersey in 1916. In just over 100 years, they have become ubiquitous in the eastern United States. Why? They have very few natural predators – even birds don’t want to eat them.
As larvae, these pests generally live on lawns and feed on grass roots. They are whitish maggots of various sizes but up to an inch long. If you cut open a square foot of lawn with a sharp shovel and peel back the lawn, you will likely see a maggot or two. If you count 10 or more in this sample, you have an infestation that is a problem.
The U.S. Department of Agriculture developed a compound called Milky Spore in the 1940s, a bacterium that can be suspended in water and sprayed on lawn. It’s not a miracle cure and it’s quite expensive. Not all entomologists believe milky spores are an effective cure, at least not in New England, where cold winters can kill the bacteria.
Not only that, those damn Japanese bugs are flying. So all you can do is treat your lawn with milky spores to keep your neighbour’s bugs flying over the fence and attacking your roses. I once spoke to an enterprising gardener who convinced her neighbors to treat too, and she feels that doing so has significantly reduced the number of bugs.
What else can you do There are useful nematodes (unsegmented worms) called Hb nematodes that attack Japanese beetle larvae and, when used correctly, are 96% effective against Japanese beetle and rose beetle larvae. The best time to apply these nematodes is July and August when the maggots are feeding your lawn. If you buy them, carefully follow the instructions: they need to be applied to damp lawns at dusk, and then watered. These are live worms, so they need to be used soon after you buy them. As a rule, they are not available in garden centers, but online.
What about those Japanese bug traps? Give them to neighbors you don’t like. They attract a lot of bugs, but only a few – they will attract more hungry bugs to your property if you use them. Really, just don’t buy them.
I firmly believe that the best way to control insects for most nasty insects is to hand-pick them and drop them in soapy water. Insects often have several life cycles in summer. So try to reduce the numbers before they multiply.
For example, hand picking works for potato bugs if you check your plants early in the season, before a large number has appeared. Look under the leaves: if you see orange masses of eggs, scrape them off and drown them in soapy water along with the beetles and larvae. If you grow too many potatoes to handpick insects, try something called “Bt,” another beneficial bacterium. It is easily available in garden centers. It does not act as a contact poison, but makes the larvae sick so that they no longer eat and do not reach adulthood.
My insect enemy is the striped cucumber beetle. It’s a tiny striped beetle that can devour a whole little plant in one night. Not only does it eat cucumber leaves, but everything in this family, including pumpkins and gourds. I do two things to prevent their destruction: I grow my seedlings in pots until they have three to four leaves so that the beetles cannot kill the plant in one night. And I cover my plants with row covers (breathable garden fabric) to physically keep those damn bugs off the leaves. That’s not to say they can’t get through the floor under the ceiling, but the method helps. And when the blooms come I have to remove the row covers to allow pollination.
Can you create habitat for beneficial insects? For sure. Don’t manicure every inch of your yard. Leave a few dead twigs or decomposing flower stalks in piles on the edge of your property. Let fallen leaves serve as mulch. Consider building a simple structure for individual wasps (such as those fighting those pesky tomato hornworms). They are sold next to the bird feeders in the garden center.
I’m afraid mosquitoes, black flies, and deer ticks have given all insects a bad name, but most are beneficial. They pollinate, serve as food for young birds and help prevent vigorous plants and other insects from taking control. And please remember, if you decide that spraying pesticides is easier than the organic methods outlined here, know that those same sprays kill small beneficial insects that you probably won’t even notice.
Henry Homeyer is a gardening consultant and author of four gardening books. He can be reached at henry.homeyer@comcast.net. His website is Gardening-Guy.com for more information and archived columns.
