Aphid damage usually appears first as leaf discoloration and sticky spots, which form from the honeydew the pests secrete. These soft-bodied insects damage plants by piercing the leaves and stems, then sucking out sap. Aphids are green, yellow, red or brown, and pear-shaped. They usually reproduce into colonies that congregate on the underside of leaves. A bad infestation results in curled, wilting foliage and weak plants. Although aphid feeding may not kill a vegetable plant. They often spread viral and bacterial diseases, which can wipe out an entire crop. Finding the pests early and destroying them can save the plants.
Remove all weeds within and surrounding the vegetable bed. Aphids often spread from nearby weeds into vegetable gardens. Keep the weeds pulled or cut down for the duration of the growing season.
Inspect the vegetable plants twice weekly for aphids, especially when temperatures are between 65 and 80 degrees Fahrenheit. Check the underside of leaves and along the stems for colonies of the insects.
Fill a bucket with warm, soapy water. Cut off aphid-infested leaves and submerge them in the soapy water to destroy the pests. This method works best when plants have only a minor aphid infestation.
Fertilize with a time-release, urea-based fertilizer instead of using synthetic nitrogen fertilizers on your vegetable plants. Too much nitrogen applied at once to the plants can result in an increased aphid population.
Spray infested plants with a sharp spray of water and rinse the aphids from the foliage. Repeat daily until the pests are gone. Aphids rarely find their way back to the plant after you knock them off.
Treat badly infested plants with an insecticidal soap or neem oil spray, following package application instructions. For most sprays, apply them directly to the infested portions of the plants, coating the aphids. Repeat applications every two to three days until the aphid population decreases.
Things You Will Need
- Liquid soap
- Urea-based fertilizer
- Insecticidal soap or neem oil
- Covering garden beds with an aluminum foil mulch before you plant can prevent aphid problems on your vegetables.
- Beneficial insects, including parasitic wasps and lady beetles, feed on aphids. Although you can purchase lady beetles to release in your garden, most will fly away before the aphid population is under control.
- Although some pesticides are sold for aphid control, soap and oil sprays are safer for edible plants, since they produce no harmful residues.