Infestation solutions in kitchen and garden> Companion plants handy way to ward off pests

I recently returned from a trip to Montreal to bug-eaten morning glories. As soon as I saw the unusual lacy pattern that had been munched out of the leaves, I knew the pest was none I had seen before. Further examination of the leaves revealed the culprit — a Japanese beetle — a whole family, in fact.

I had heard terrible things about Japanese beetles — the damage they do, the crop failure they cause, and the difficulty they present with control. But I also had heard that they haven’t moved this far north yet. I’m disappointed to find those reports no longer hold true. These insects are among the most tenacious; not only do the adults feast on both leaves and flowers, the grubs feed on roots and underground stems. They are unusual pests which call for unusual types of control.

Some people use pheromone traps to rid their garden of Japanese beetles. Pheromones are chemical substances released by insects to mark territory, attract mates or alert other insects of the same species of danger. Pheromone traps for Japanese beetles contain the chemical the beetles use to attract mates. Its design lures the beetles in and then they are unable to escape. The only problem with the trap is that it may perform too well. It may attract more beetles than you would normally have in your garden. Instead of making their way into the trap, they may find alternative mates and reproduce right there where they are least welcome.

Spraying the insects with commercial house and garden pest killer sprays is one way many people get rid of the loathsome critters. But spraying plants with loads of chemicals isn’t too appealing to those who grow a garden to have chemical-free foods.

One alternative to chemical controls is to plan companion plantings or prepare pest controls with materials from your kitchen and garden. Some folks use companion plantings of catnip, chives, garlic and tansy to repel Japanese beetles in host plantings. Others spray slurries (repellent herbs steeped in hot water) over the host plantings. Japanese beetles “smell” the undesirable herbs and fly off in search of more palatable food.

Japanese beetles aren’t the only insect pests repelled by potions from the kitchen and garden. Aphids, cabbage looper, earworm and squash bug are among others easily repelled. My husband prepares a tea which effectively wards off the aphids on his hot pepper plants and the cabbage looper on his bok choi. He won’t reveal the concoction’s secret ingredients, but I stole a peek when he prepared the potion recently and noticed garlic, hot peppers, marjoram, oil and dish detergent on the counter top. He was steeping several tablespoons of the herbs in a cup or two of hot water. A tablespoon of oil and dish detergent were added before he sprayed the cooled substance on his plants.

Any number of herbs repel a number of pests. Almost any aromatic herb, such as mustard, garlic, nasturtium, mints, eucalyptus, chives and catnip, will repel aphids, cabbage looper, squash beetles and flea beetles. Ornamental herbs such as cosmos, geranium, marigold and petunia repel leafhoppers and the corn earworm. Plantings of wormwood (or silvermound) repel mice, slugs and ants.

Much of the information about herbal pest controls was passed to novice gardeners and herbalists from those with more experience. The expertise the more seasoned gardener gained was less from scientific confirmation and more through experimentation and unbiased observation. This makes it, I guess, a type of “herb lore” passed within the gardening community. Although science is quickly catching up and defining exactly what makes pests and plants complementary or opposing, the simple fact that some things work without technical explanation is good enough for me.

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, 1243 State St., #2, Veazie 04401. Selected questions will be answered in future columns. Please include your name, address and telephone number.