Aphid Control for Roses
Aphids, commonly known as plant lice, are common pests of ornamental plants, including roses.
What do Aphids look like?
Aphids are up to 1/4 inch long green, yellow, pink, brown, gray or black insects that can both be winged or wingless. The color depends on the species and type of plant that the aphids feed on. Some aphids may be waxy or wooly in appearance. The body of aphids is pear-shaped with long legs and antennae.
Aphids most frequently are found in dense groups feeding on young stems and leaves.
|Aphids on Roses|
Aphids on roses
Aphids generally do little physical damage to your roses. Only large numbers of aphids can cause leaf curling, yellowing and distorted growth of leaves and stunting of new shoots. Leaves of your roses are usually sticky with honeydew (aphid excrement) or blackened by sooty molds (brown and black fungi).
The most devastating damage occurs when aphids transmit viruses to your roses while feeding on their sap.
How to control Aphids
Environmental Controls. Healthy plants are the key to limiting damage caused by aphids. Aphids in flight are often attracted to yellowing foilage of weakened plants. Healthy, well watered and fertilized plants will more easily tolerate the stress caused by aphid infestations. High levels of nitrogen in the soil will favor aphid reproduction. To reduce the number of aphids on your roses, use a time-release fertilizer containing urea instead of nitrogen.
Chemical Control . Applications of insecticidal soap and Neem Oil can help control aphids during heavy infestation periods. However, it may be necessary to repeat applications frequently as insecticidal soap and neem oil only kill aphids currently on the plant and do not provide any residual protection. Use of broad-spectrum insecticides may actually do more harm than good as they also kill natural predators of aphids.
- Natural Predators. Aphids can be controlled by natural predators such as ladybugs, lacewing, and certain species of wasps. When these predators occur naturally they can be very effective at controlling small to medium aphid populations. If roses have been sprayed with broad-spectrum pesticides many naturally predatory insects may have been killed also and additional aphid control measures should be taken.