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Tips for Preventing Garden Pests and Diseases

Preventing Garden Pests

If your garden is filled with pests, don't just reach for the pesticide. There are other, safer, methods to use to keep garden pests at bay.

  • Interplant herbs and flowers with vegetables to help reduce pest problems. This gives the vegetable garden a colorful patchwork look and helps confuse problem pests. The varied aromas of interplantings make it hard for pests to find their favorite food by scent. This works particularly well if you interplant with powerfully fragrant herbs and flowers such as mints, basils, lemon geraniums, garlic, or onions.

  • Attract beneficial insects. Sprinkling flowering plants amid the garden helps draw ladybugs, spiders, lacewings, and tiny parasitic wasps who prey on plant-eating pests. The flowers provide shelter plus nectar and pollen, an alternative food source.

    Once beneficial insects are at home in your garden, keep them there. Remember, they can be killed as quickly as plant pests by broad-spectrum pesticides, which kill indiscriminately. It's best to avoid pesticides or use targeted pesticides such as Bt (a bacterial disease of caterpillars that won't harm other insects) to protect beneficial insects.
  • Use floating row covers to keep pests off vegetables. This simple idea works so well it's a wonder nobody thought of it years ago. Floating row covers are lightweight fabrics that you can drape over plants. They allow sun, rain, and fresh air to penetrate, but if secured to the ground with rocks, bricks, or long metal staples, they will keep flying insects out. Here are some great ways to use floating row covers:
    • Eliminate maggots (fly larvae) that will tunnel into the roots of radishes, turnips, carrots, onions, and other vegetables. Row covers keep egg-laying female flies away from the vegetables. If there are no eggs, there are no maggots.
    • Keep potato beetles from eating the foliage off potato leaves and vines. Pin the row cover edges down tightly so the beetles can't crawl under.
    • Protect cucumbers, squash, and pumpkins from cucumber beetles, which carry a wilt disease capable of killing entire vines. Since flowers of these vines need insect pollination for fruit set, the covers must be lifted for several hours at least every other day for honeybees to do their work.

  • Use barriers of copper strips or diatomaceous earth to keep slugs away from plants. Slugs are voracious plant eaters. They eat almost anything, ganging up on tender succulent plants and eating them down to the ground. They thrive where soils are damp, spending sunny days under rocks, logs, or mulch and coming out to eat when it's rainy or cool and dark. Any slug control measures you use will work better if you clear out excess mulch and any dark, dank hiding places where slugs might breed.
    • Diatomaceous earth is a gritty substance that pierces the skin of soft-bodied slugs. Sprinkle it on the soil, encircling plants plagued by slugs. Use horticultural-grade diatomaceous earth, not the kind sold in swimming pool stores.
    • Copper strips, set around the edge of the garden, prevent slug trespass by creating an unpleasant reaction when touched with the mucus on the crawling slugs. Set copper strips an inch deep and several inches high, so that slugs can't get over or under.

  • Kill existing slugs by trapping them in deep saucers of beer. Slugs love beer, and that can be their downfall. Bury an empty plastic margarine tub in the garden soil. The top rim should be level with the soil surface. Fill the tub with beer (any kind will do) and leave it overnight. The slugs will crawl in and drown. Empty the tub every day or two and refill with beer until the tub comes through the night empty.

    Use a strong spray of water to get rid of aphids.
    Use a strong spray of water to get rid of pesky aphids.

  • Spray aphids off plants with a strong stream of water. Aphids, small sap-sucking insects with soft, pear-shaped bodies, cling to succulent young stems and buds. They reproduce quickly, sometimes covering stems that curl and distort in protest. Because aphids can multiply into swarms almost overnight, it's important to eliminate any that you find.Before hauling out any pesticides, try a strong blast of water from the hose. Aphids are easily dislodged from plants. This method works best on mature or woody plants that won't be damaged by the force of the water blast. Repeat every couple of days or any time you see new aphids arriving.
  • Use bags of soap or human hair to repel deer. Sometimes called jack rabbits on hooves, deer can be a nuisance. They seem to enjoy dining on cultivated plants and are worst in the winter, gobbling evergreens when their native food supply dwindles. But they are also a problem in spring and summer, when they like to munch tender flowers and new growth. In fall, males rub their antlers on wood and can damage small trees and shrubs. However, they don't enjoy strong-smelling soaps and human hair.

    Powerfully scented soap can be stuffed in a mesh bag and dangled from branches about 3 feet high. You also can set soap bars directly on the ground. Replenish the soap supply frequently so it won't dissolve away or lose its smell.You can also fill mesh bags with human hair. Hang them outside (like a furry scarecrow) so deer wonder if you are hiding in the garden. Refill bags as soon as you pull another handful from your hairbrush.

No one wants disease or pests to ruin a beautiful garden. Be mindful of the tips outlined in this article, and you'll be more protected from these pesky outside forces.

Some Plants Preferred by Deer
Based on Cornell Cooperative Extension Service research, the following plants are attractive to deer:

Want more gardening tips? Try:

  • Gardening Tips: Learn helpful hints for all of your gardening needs.
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  • Gardening: Discover how to garden.