Pest Control: Attracting the Good Bugs

Credit: Terry Guscott

What we consider “bad” bugs are primarily vegetarians, eating only plants, while “good” bugs consume other insects. To attract these good bugs into your garden, and keep them happy enough to stick around and start a life cycle, you will need to consider three basics: water, shelter and food.

Providing water to beneficial insects during the summer is simple. A birdbath or shallow pan with clean water will do, but be sure to add a few large rocks for the insects to perch on. Low puddles, ponds, creeks and other natural water sources will also work.

Shelter is the next step. The key is to ensure that good bugs have a stable habitat with protection from mowing, rototilling and other disturbances. Permanent pathways, plots of cover crops, perennial borders, large rocks and shrubs will provide beneficial insects with adequate permanent housing. And in the vegetable garden, a small crop cover plot such as buckwheat or rye will give bugs a place to shelter on hot summer afternoons.

When looking for their meals, beneficial insects will source out sweet nectar (for carbohydrates), pollen (for protein) and pest insects and/or their larvae and eggs. Beneficial insects can easily eat several times their weight in pest bugs, but that doesn’t mean they will eat all the pests; they know better than to cut off their food source. They will, however, reduce the population to a minimal level that healthy plants can easily resist.

The annuals and perennials we plant provide insects with nectar for food, as well as foliage for nesting. In order to feed beneficials throughout the season, plant early, mid and late-bloomers with ferny or fragrant foliage in which the insects can nest. Favourite annuals of good bugs include scented geraniums, marigolds, alyssum, cosmos, zinnias and sunflowers. Popular herbs are lavender, parsley, chives, coriander, dill, fennel, tansy and thyme, while favoured perennials include echinacea, asters and daisies, as well as columbines and golden rod. The columbines provide early-season food, whereas the golden rod feeds later in the season when other perennials have finished. Beneficial insects are also attracted by such plants as blanket flowers, bachelor’s buttons, butterfly bush, carrots that have gone to seed, feverfew, coreopsis, lady’s mantle, yarrow, milkweed and Queen Anne’s lace.

Of the common pests that regularly invade our gardens – aphids, caterpillars, slugs, snails, whitefly and weevils – all luckily have a natural predator that we can easily attract. Ground beetles will attack slug eggs; hover flies and ladybugs will go after aphids; and parasitic wasps will control caterpillars. In the soil, an application of beneficial nematodes will help to reduce weevil and leather jacket larvae. Whitefly may also be controlled by beneficial nematodes and hover flies. If you want a head start on increasing your natural predator population, or you find your initial resident population rather small, you can add to it by purchasing beneficials at local garden centres or from mail-order insect companies on the Internet.

Once you have established a balanced insect population, be extremely careful when it comes to the use of chemical insecticides. Good bugs are particularly sensitive. Alternatively, some bad bugs have been able to build up a resistance to certain products. Therefore, if a spray is applied or drifts in, it can quickly ruin the ecosystem that you have worked so hard to create.

So, when hunting through your garden for beneficial critters and insects, be sure to give a thank-you to the earthworms, hummingbirds, butterflies and spiders for their help in aerating, pollinating and controlling pests. And be sure to encourage them to stick around.

Aphid Control Spiced Up

Aphids are common summer pests. We find the soft-bodied, green or black insects on fruit trees, roses, pepper plants, etc. Many of us have tried a spray of vegetable oil and water to combat the problem, which sometimes works, but is not always quite enough. If you find that your aphids are extra tough-skinned this season and won’t respond to the usual remedy, spice it up a notch with peppers and garlic. This easy-to-mix spray will help paralyze the pests.

• 3 cloves garlic, chopped fine
• 1 tsp. (5 mL) grated horseradish
• 2 crushed and chopped hot chilli peppers
• 6 cups (1.5 L) water

Mix together all ingredients and boil for one minute. Cool and strain (a coffee filter or cheesecloth works well). Pour mixture into a spray bottle labelled “Aphid Attacker” and keep on hand when patrolling for the pest. To attack, locate pest, point and spray.

Note: Keep away from sensitive plants such as sweet peas, ferns, nasturtiums and begonias.