Aphid Control Guide For Trees

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Sticky leaves can indicate a pest problem on your trees. The cause is aphids, small pear-shaped insects that feast on the saps and juices in the leaves. The aphids themselves rarely harm the tree, the issue is with the sticky "honeydew" they secrete. It creates the perfect breeding ground for powdery or downy mildew. The following guide can help you spot an aphid problem and provide tips for controlling it.

Susceptible Trees

Some trees are more prone to aphid problems than others. Fruit trees, such as apple, cherry or pear, are especially susceptible, as are ashes and maples. Conifers aren't immune to aphids, but they are more resistant to disease damage than deciduous trees. For this reason, deciduous trees are the main ones to watch for infestation.

Aphid Symptoms

Aphids tend to congregate in clusters on the underside of leaves. They are usually green, yellow, brown, or black in color. They leave behind the sticky honeydew, which can attract ants into the canopy of the tree. Badly infested leaves may curl up and die. The leaves may also simply turn yellow and appear stunted. If mildew takes hold, a powdery gray or thick black mold may begin growing on leaves and stems.

Control Options

There are several different ways to handle aphids. If a tree is large and otherwise healthy, a small aphid infestation isn't usually a concern. You may be able to get rid of a small population by simply rinsing the foliage off with a sharp spray from the hose. The following are a few more options for control:

• If ants are present on the tree, they may be protecting the aphids in order to "farm" the honeydew. There are sticky strips available that you can wrap around a tree trunk. These prevent the ants from climbing up the trunk to the aphids.
• Ladybugs feast upon aphids. You can purchase lady bugs from garden stores to release in your tree. They will help control the aphid population.
• Tree sprays are available to help control the pests. There are soap-based sprays that coat the aphids and kill them, but the tree foliage must be rinsed with clear water a few days later so the spray doesn't harm the leaves of the tree.
• Pruning is sometimes needed, especially if there are dead or weak branches that are attracting the pests. A tree trimmer can locate the problem branches and prune carefully so the health of the tree isn't compromised.

Talk to a tree care specialist in your area for more help with controlling tree pests.  

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14 June 2016