When you see tree leaves dripping sap, the usual cause is tree aphids. These pesky insect pests can cause serious stress to your trees and lead to disease. Learn more about aphids on tree limbs and foliage and what you can do for tree aphid treatment.
What are Tree Aphids?
These tiny, soft-bodied, pear-shaped insects can be almost any color. Aphids on tree foliage and shoots feed by sucking fluid from the tree through a slender mouthpart called a proboscis. They feed in clusters, usually on the undersides of leaves near the point where the leaf attaches to the stem, or on tender young shoots and buds. As they feed, they secrete a sticky fluid called honeydew. When enough aphids are feeding on the tree, this honeydew will begin dripping from the leaves.
Aphids Tree Disease Issues
Some tree diseases are spread by aphids, especially fungal diseases. Tree disease is much more serious than aphid infestations, and can kill or seriously damage a tree. To prevent the spread of aphid tree disease, keep the tree as healthy as possible to support its natural defense against disease and control the aphids as much as possible.
Tree Aphid Treatment
The first step in controlling aphids is to control the ants that feed on the honeydew they secrete. Ants protect aphids from their natural enemies to ensure a continued supply of honeydew. Bait traps are effective, but read the label carefully, and only use traps that are safe around children, pets, and wildlife.
Tree aphids have a number of natural enemies that help keep their populations in check. When trying to control aphids, keep in mind that you want to preserve these beneficial insect populations. Beneficial insects are much more effective at controlling aphids than insecticides, and the use of strong insecticides can make aphid infestations worse.
You can remove aphids from small trees with a strong spray of water from a hose. Aphids that are knocked off of a tree are unable to return. Spraying the tree with neem oil or insecticidal soap helps control aphids without harming beneficial insects, but the spray has to come into direct contact with the aphid to be effective. Spray the tree until the insecticide drips from the foliage. It may take several applications to eliminate the aphids.
Insecticides that contain ingredients such as permethrin, acephate, malathion, diazinon, or chlorpyrifos are effective against aphids, but they are also effective against beneficial insects and may only make the problem worse. Use them only as a last resort.
Now that you know a little about what causes tree leaves dripping sap, you can take the correct steps in preventing and treating aphids on tree foliage.