Don't Let Pests Get the Best!

originally appeared in the Project Grow Newsletter, Summer 2006
photo by Ikes under Creative Commons license

In your garden, have the seeds sprouted with a fine rate of germination, only to be nibbled to the ground? Have you babied those cucumbers, only to have the plant destroyed by insects? Or how about the green worms on your broccoli—that you find at the dinner table? Gardening by its very nature includes nature, all of it, including what we think of as “troublesome pests.” In the same manner that plants are always growing and changing, so the pests in your garden may change and adapt year after year as well.

For optimum pest control, identifying the culprit is key. It is not useful or recommended to kill all the insects that you find on a plant, or to even eliminate all the “bad guys.” By removing all of a particular insect you run the risk of eliminating its predator as well, thus, creating a perfect situation for the pest to return in force.

You can also develop garden practices that will contribute to a healthier garden overall and certainly help in the control of unwanted insects. These healthy garden practices include good garden sanitation—removing diseased and infested plants from your garden, promptly getting rid of pest-ridden plant material, and rotating crops. Try companion planting—planting basil among tomatoes helps control hornworms, combining thyme or tomatoes with cabbage plantings controls flea beetles, cabbage maggots, white cabbage butterflies and imported cabbageworms. You can also sow catnip by eggplant to deter flea beetles, grow horseradish with potatoes to repel Colorado potato beetles, set onions in rows with carrots to control rust flies, grow radishes or nasturtiums with your cucumbers for cucumber beetle control. Nasturtiums also deter whiteflies and squash bugs, but they are most often used as a trap for aphids, which prefer them to other crops. Be sure to encourage beneficial insects and animals.

Did you ever consider repelling with smell? In his book “Your Organic Garden,” Jeff Cox writes about how night-flying moths approach flowers by flying upwind. If netting is placed over flowers the moths will still land and feed, indicating that they react to flower odor. If pests can’t smell your plants, maybe they will go elsewhere. Jeff recommends planting scented marigolds as thickly as you can around your garden. Mint is another fragrant plant, but since it quickly grows out of control, set it in pots around your garden. The oil from the leaves of rue can give some people a poison ivy-like rash, but this trait also deters Japanese beetles. Rue can be helpful grown as a border or scatter the leaf clippings if Japanese beetles are a pest. Sweet basil interplanted in the vegetable garden repels aphids, mosquitoes, and mites.

“Your Organic Garden” also lists a few home-brewed pest controls that many of you may already be familiar with. Results from these brews are certainly not guaranteed, so keep an eye on plants to monitor their effectiveness.

• Bug Juice: ½ cup of specific pest, mash well, mix with 2 cups water and strain. Mix 1/4 cup of this bug juice with a few drops of soap and 2 cups water and spray (wear gloves and always use nonfood utensils)
• Garlic Oil: Finely chop 10-15 garlic cloves and soak in 1 pint mineral oil for 24 hours. Strain and spray as is or dilute with water and add a few drops of soap.
• Hot Pepper Spray: Blend 1/2 cup of hot pepper with 2 cups water, strain and spray. Remember hot peppers burn eyes and skin.
• Killer Cooking Oil: Combine 1 tablespoon of dishwashing liquid with 1 cup of vegetable oil. Add 1 to 2 1/2 teaspoons of the oil/detergent mix to 1 cup of water and spray on infested plants once every seven days.
• Firewater: Mix two to four jalapeno, Serrano or habanero peppers, three cloves of garlic, and 1 quart water in a blender, or chop the peppers and garlic and let them steep in a quart jar of water set out in the sun for several days. Strain through cheesecloth, spray as needed, reapply after rain.
• Alcohol spray: Combine 1 to 2 cups of rubbing alcohol with 1 quart of water. Test spray a small area on one plant. Wait a day to check for damage before spraying entire plant. Or add between ½ and 1 cup of rubbing alcohol to 1 quart of insecticidal soap or horticultural oil sprays to increase effectiveness.