Slugs and Salal - Natural Pest Control

A Natural Approach to Garden Pests

If you tend to panic at the sight of bugs in the garden, remember this: A mere one-tenth of one per cent (.1 per cent) of insects are destructive to our plants. Of the rest, many are our allies, helpful in some way to the health of our gardens. Something else to ponder: When we kill one of these beneficial insects with pesticides, we then inherit its job -- a job whose complexities we are ill equipped to manage.

Since I stopped using toxic sprays many years ago I've noticed a proliferation of beneficial insects in my garden. Ladybugs are everywhere, and under just about every plant and rock I'll find a shiny black ground beetle, voracious hunter of slugs and other pests. The beetles are almost iridescent, and about one inch (2.5 cm) long. Don't step on them. They are a gardener's friend and ally.

Pest Control Pointers

Get to know your bugs: Observe garden creatures carefully before squishing them into bug heaven. Many of the most ugly worm-like creatures found in the garden are the larvae of beneficials. If they are equipped with ferocious looking pincers or jaws, or if they move fast, you can be fairly certain they're geared to catching and feasting on other insects such as garden pests.
Grow plants that attract good insects: I try to keep beneficial insects that feed on aphids, cutworms, mites and other pests attracted to my garden by leaving patches of their preferred food plants to self-sow and bloom throughout the garden. These plants include fennel, dill and parsley. Yarrow, goldenrod, black-eyed Susan, Queen Anne's Lace and evening primrose are more good pollen-rich flowers for attracting beneficials.
Keep your soil healthy

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Use Reemay, the earth-friendly bug deterrent

It's not that my garden is pest-free. There are some vegetables that I could not grow at all without taking preventive measures against insect pests. The carrots would be ruined by the rust fly. Cabbage root maggots would tunnel into the roots of the cabbages, broccoli and cauliflower and cause them to wilt and die. And the beets would be ruined by leaf miner larvae tunnelling inside the foliage.

To protect these plantings I tuck a floating fabric row cover such as Reemay into the soil around the seeded or transplanted bed as a barrier to prevent the winged adult forms of these pests from laying eggs in the plantings. When seeding the carrots and beets, or setting cabbage family transplants into beds, I make sure that the planting areas are made narrow enough to allow plenty of slack in the floating cover fabric so there is room for the plants to expand beneath it. These covers allow free passage of air and water to the plants and soil.

As the plants develop, they lift the lightweight fabric. My lengths of Reemay usually last two years before they begin to tear. A more long-term barrier, if you have a handi-person in the family, is a screened box to set over the carrot seed bed.

I leave the Reemay on the carrots until winter, when I hoe a soil cover over the roots after the tops have withered and have been cleaned away. This soil cover gives frost protection and camouflages the carrots' presence. The flies, in my experience, remain active in all but the most severe weather. An added protection against the flies (and the weather) would be a sheet of plastic secured over carrots to be overwintered.

The Reemay actually does double-duty in the cabbage, cauliflower and broccoli patch as a barrier also to gray cabbage aphids, and the cabbage loopers and caterpillars that are the larvae of a brown butterfly and the familiar white butterfly. Once the plants are uncovered, a strong jet of water to force the pests off the plants can be used for aphid control.

See how sawdust works

An alternative to the Reemay cover over cabbage family vegetables as a shield against the cabbage root maggot is a barrier to the fly set snuggly around the plant stems. This can be a ring of sawdust two inches (five cm) thick and eight inches (20 cm) across, or tar paper collars. These barriers inhibit the fly from laying eggs at the bases of the plants.

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Treatments for specific bugs

Dealing with slugs: Small dark or light gray slugs are a devastating pest in many coastal gardens. An important defence against them is to keep the garden as clear of debris as possible. Boards or inverted grapefruit halves set out in the garden serve as traps from which slugs can be gathered in the morning. Small dishes, pie tins or the smallest size sour cream containers sunk to the rim in the ground and filled with beer (or a teaspoon of baking yeast in water) will attract and drown slugs. Use commercial baits only in covered traps. I protect my lettuce plants from slugs with a line of crushed eggshells. [ more on slug control ]
Aphids affect all gardens: There's a strain of aphid for just about every plant in the garden. These soft-bodied plant lice can be hosed off plants, with followup sprays of Safer's Insecticidal Soap to catch malingerers. That leaves the nasturtium, oasis of feeding pleasure for black aphids and a plant for which the insecticidal soap is not recommended. Try forcing the aphids off the plants with a water spray, and dust with rotenone if necessary. Follow label directions and cautions carefully. Try growing nasturtiums with tomatoes. Some people find they can grow aphid-free nasturtiums this way.
Spider mite management: Spider mites are minuscule creatures that gather on foliage undersides and suck plant juices. Leaves take on a dried, grotty look with speckles and webbing along leaf undersides and in stem crotches. Mite populations soar in hot, dry conditions and they prosper where toxic sprays have knocked out their natural enemies.; Try to catch a spider mite infestation at its early stages before populations build. Spray-wash infested plants every second morning, using a forceful jet of water and making sure to hit the leaf undersides. Follow the washing with three or more sprays of Safer's Insecticidal Soap or Safer's Spider Mite Killer spaced at seven-day intervals.