Insects and Pesticides – Good and the Bad

Sooner or later, we will have to recognize that the Earth has rights, too, to live without pollution. What mankind must know is that human beings cannot live without Mother Earth, but the planet can live without humans.

  – Evo Morales

Scientists estimate there are approximately 20,000 varieties of insects and that 97%-99% of the insects are either harmless or beneficial.  Some beneficial insects pollinate flowers, vegetables, and fruit trees; others help to keep pests under control.  Unfortunately, many pesticides and lawn chemicals kill all insects, seriously impacting the productivity of our gardens.

Pollinators in the urban garden include bees, hoverflies, butterflies, moths, wasps, flies, ants, midges, beetles and, believe it or not, mosquitos.

Some beneficial insects prey on garden pests.  Parasitic wasps lay eggs in caterpillars; the larvae eat the host and the host eventually dies.  Parasitic flies lay their eggs on the larvae of butterflies, moths, beetles, sawflies, and other insects, killing them. Lady beetles and lacewings eat aphids.  Beetles eat insect eggs, larva, adult mites, aphids, and other pests.

Attract pollinators and beneficial insects to your garden by providing habitat for them.  This includes some bare ground for underground bee tunnels, shrubs, a variety of herbs, and flowers so that there are blooming flowers throughout the season.

Attract birds, especially the insect-eating ones such as wrens or robins, by providing tree or bush cover, birdbaths, and birdhouses.  If you want birds, don’t kill the bugs.

Start your pest control by regularly inspecting your garden, catching infestations before they get out of control.  Rotate your crops; pests tend to lay their eggs where they hatched. When host plants have moved, their offspring may not find them.  Keep your garden free of weeds.  Remove infected foliage quickly; do not compost it, place it in your landfill garbage.  Healthy plants are more likely to resist garden pests.  Hand-picking larger bugs such as the Colorado potato bug or the lily beetle is generally more effective than using a pesticide.

Row covers, a cloth that lets in 80% of sunlight and rain, protect root vegetables such as turnips or radishes from root maggots and prevents cabbage butterflies from laying their eggs.

Don’t panic.  You could lose up to 40% of a plant’s foliage and not seriously reduce the amount of produce.

These defenses minimize damage from garden pests, but in some cases the pests gain control. Use the following organic pesticides; they are safer because they target specific pests.

  1. Bt (Bacillus thuringiensis), kills many types of caterpillars such as the cabbage worm by producing crystals that paralyze the digestive tract.
  2. Neem Oil on targeted plants kills insects that are eating the plants. It may also stop fungi and mildew. For lily beetles, spray the ground as the plants start to emerge and spray every three days until there is no evidence of grubs, beetles, or holes in the leaves.
  3. Spinosad kills flea beetles found on potatoes and other plants. While safe for birds, and many insects, it is highly toxic to bees. Do not apply it to blooming plants or where bees are actively foraging.
  4. Bordo is used as a fungicide to prevent infestations of downy mildew, powdery mildew, and other fungi. Use it before the fungus is established.
  5. Use insecticidal soap on aphids, mites, and whiteflies. You may have to apply it every two or three days for two weeks for bad infestations.
  6. Pyrethrin is derived from the flowers of pyrethrum daisies. A heavy dose is needed for flies, mosquitoes, and aphids.
  7. Slug Be Gon is a bait that stops slugs from eating. What isn’t consumed degrades and becomes part of your garden soil.  While Slug B Gon is effective you will still have to handpick some slugs.

Please avoid harmful herbicides and pesticides on your lawn and garden; most commercial pesticides kill beneficial insects.

My next article is on maintaining your garden in the summer.


One Response

  1. Love your article – but where do you purchase Neem Oil and castille soap for pest prevention PLEASE REPLY. I have tried every garden center and
    nobody carries these items. I have a large flower garden and I need to mix my own pest prevention for the flowers and plants. PLEASE HELP

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