Natural Bug Killer for Vegetable Plants

Bacillus thuringiensis

• Bacillus thuringiensis (Bt) is one of the few bioinsecticides available that is completely harmless to humans and allows you to harvest the same day that you spray. Bt var. kurstaki kills caterpillars by binding their digestive system so they starve to death. Bt is also a non-contact insect killer, which means that you do not have to spray each caterpillar. It works by ingestion, so spraying the plant is enough. Bt kills cabbage loper, tomato hornworm, corn ear worm, tomato fruit worm and squash vine borer. Bt is approved to be used on produce sold in stores as organically grown.

Rotenone

• Rotenone is a botanical insecticide made from plants. While it is often included in the realm of "natural" products, rotenone is toxic to fish, bees and other wildlife. It is also toxic to humans, so you need to wait a least a day after spraying before harvesting. Rotenone is a contact insecticide, so you need to spray when the insects you want to kill are present. The toxicity of rotenone is of concern, and it cannot be used on produce sold in stores as organic. Because of its toxicity, use rotenone with caution. Rotenone works mostly on beetles, including the spotted cucumber beetle, potato flea beetle, cabbage flea beetle, scale, mealy bugs and others.

Pyrethrum

• Pyrethrum is a botanical insecticide made from a variety of chrysanthemum. It is a contact insecticide that paralyzes the insect when hit with the spray. Pyrethrum is toxic to fish, birds and other wildlife. You cannot harvest the same day you spray.

  Pyrethrum kills cutworms, whiteflies and aphids, among other insects. It is sometimes combined with rotenone to be more effective on a wider variety of insects. As with rotenone, pyrethrum should be used with extreme caution. It is not approved for use on produce sold as organic.

Other Natural Methods

• Insecticidal soap can be used to control aphids, scale, mites and other soft-bodied insects. It is organic and biodegradable. It can be used on produce sold as organic. The biggest drawback is that it cannot be used on plants growing in full sun, as it damages the leaves.

  Sometimes barrier methods are a good choice for prevention, as they keep insects off the plant entirely. Summer-weight floating row covers can be used in cooler areas but need to be removed when temperatures rise above 80 degrees Fahrenheit to prevent plant damage.

  Hand-picking insects and destroying them is a good way to control insects naturally.