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Encouraging Beneficials
by Julie Ferraro
by Julie Ferraro

November 14, 1999

Your garden can host far more beneficial organisms than pests. Enticing beneficial insects and animals to your garden is a form of biological pest control. While you can buy and release beneficials into your garden, you're better off encouraging them to take up residence instead. Many beneficials are migratory and won't remain in the garden if they can't find the food or shelter they need. Here are some of the ways to encourage predators and parasites that prey on insect pests to come into and stay in your gardens.

  • Provide food and shelter to attract insect-eating birds. Birds are seldom credited for all their help in controlling flower garden pests. Birds will harvest thousands of insects during the weeks when they raise their young. Baby birds cannot digest seeds and are fed fresh insects. Putting up birdhouses, planting flowers with tasty seeds such as echinacea and rudbeckia, and planting trees and shrubs for shelter will provide an inviting yard.

  • Plant pollen-producing and nectar-producing flowers and herbs as a food source for beneficial insects. There are several flowers and herbs (herbs should be allowed to flower) that will lure beneficial insects. Daisy family flowers such as artemisia, aster, chamomile, coreopsis, marigold, sunflower, tansy, yarrow and zinnias will attract assassin bugs, honeybees, hover flies, lacewings, lady beetles and parasitic wasps. Mint, bee balm, catnip, hyssop, lavender, sweet marjoram, oregano, sage, thyme, chives and onions will attract honeybees, hover flies and parasitic wasps. Carrot family plants such as angelica, anise, caraway, dill, fennel, parsley and Queen Anne's lace lure hover flies, lacewings, lady bugs and parasitic wasps. You can plant a border of these plants around the perimeter of your garden or just scatter clusters of them throughout the garden itself.

  • Put out a shallow water bath for beneficial insects to drink from. Fill a shallow dish with small stones, and add enough water to create shallow pools among the stones. Since many beneficial insects are tiny and can drown easily, be sure your bath has dry areas where they can land.

  • Put an overturned flowerpot with a hole broken in the side and a half-buried water dish in your garden to shelter and attract a toad. Toads can eat 24,000 insects in one active season. They will devour ants, aphids, caterpillars, cutworms, grasshoppers, slugs, spiders and squash bugs. Turning the porch light on will also attract toads at night and they will stay as long as they have a hiding spot or two.

  • Put up bat houses. Bats suffer from bad press. These mammals do not bother humans unless they are cornered or provoked. They venture out in the early evening to search for insects. A single bat can eat over 1,000 mosquitoes a night. If you have an abundance of night-flying insects bats are an excellent beneficial.

  • Don't chase away the garter snakes. Most snakes that find their way into your backyard only represent a threat to garden pests. Garter snakes and the like prey on rodents and snap up bugs and beetles. Allowing them to hunt in and around your flower beds will curb the population of bulb-eating voles, mice and rabbits as well as pest insects.

  • Keep soil healthy to encourage beneficial organisms Healthy soil contains fungi and bacteria that fight soilborne organisms that can cause plant diseases. Adding compost to your soil encourages the full range of helpful soil creatures. Leave stones, wood scraps or mulch around your garden for the beneficials to hide under.

  • Don't use pesticides The step that will most increase your garden's population of beneficials is limiting or eliminating use of pesticides as they kill beneficial insects as well as pest insects. Even organically accepted pesticides such as pyrethrins or rotenone are quite poisonous to beneficial insects. Use these only when necessary and choose ones that break down fastest in the environment.

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