How to Rid Your Garden of Thrips
Thrips are tiny insects that literally suck the life out of your plants resulting in pale leaves and twisted, discolored plants. One of the best ways to get rid of them is by enlisting the help of their mortal enemies.
Know your enemy
Thrips overwinter in the soil of your garden in both the adult form and as larvae. When the soil warms in the spring, the adults emerge from the soil. Females fly to your plants, make slits in the stems and leaves and lay up to 80 eggs at a time. The eggs hatch within a few days or weeks depending on the temperature and the larvae begin to feed on the plants' sap. Within two weeks, they drop to the soil to pupate into adults. Because their lifecycle is so short, there can be a dozen or more generations within one growing season.
The enemy of my enemy is my friend
Beneficial insects are the best defense against thrips. The Amblyseius cucumeris is a predatory mite that you can purchase via mail order to release into your garden where it will eat the larvae and eggs of thrips. Pirate bugs, lady bugs and lacewings also available by mail order and all love dining on thrips, as well as other pests that they find in your garden.
Use insecticidal soaps
Spraying with insecticidal soaps such as neem oil can be effective in killing thrips by smothering them. When spraying, make sure that you coat the entire plant. Don't forget the undersides of the leaves where thrips love to hide!
If you must use insecticides
Insecticidal sprays are effective in killing thrips but they also kill other insects. Insecticides make no distinctions between "good" bugs and "bad" bugs. Sprays containing pyrethrum are good choice if you are overwhelmed with thrips and must spray. Pyrethrum is potent but loses its toxicity within a few days so beneficial insects can safely move back into your garden.
Since pyrethrum is toxic for honey bees, use it early in the morning or at dusk when they are not active. The spray should be dried by the time the honey bees come looking for nectar.
Check your garden daily for signs of thrips. Cut off and discard damaged leaves. If they have infested most of the plant, remove the entire plant and discard it. Make sure that you discard your plants in the garbage and not in your compost.
Don't give them anywhere to hide
Remove all plant waste from your garden such as onion tops, weeds, and grass where thrips like to hide. Use dry mulch like wood chips because thrips don't like it. They prefer green mulches and plant waste.
More on garden pests
© 2014 Caren White