Tiny Yellow Aphids on a Live Oak

Aphids are small insects which subsist on the sap of plant shoots and leaves, and can seriously damage or weaken many plants. While many aphids are black or brown, several green and yellow species do exist and are known to infest large shade trees and hedges, as well as ornamental and garden plants. Luckily, aphid infestations can be easily controlled using a wide variety of simple and effective techniques.

Hose with spray handle
Insecticide spray applicator

Instructions

- 1
  In some cases, a hard spray of water to physically knock the aphids off the tree will do the trick. If you have a hose with a spray handle that can reach the affected tree, this can be the most cost-effective method to try first before upping the ante.
- 2
  Consider applying an insecticide to the tree and the surrounding area to treat the aphids. Because the life cycle of aphids is so short, you should look for an insecticide which provides a residual effect against the aphids. Different varieties you could try include permethrin, acephate, beta-cyfluthrin and estenvalerate.
- 3
  Apply natural predators if you'd rather use an organic, long-term option, or have other reasons (such as a pet in the yard) to shy away from insecticides. Many garden supply stores may be able to supply natural predators to aphids, such as lady bugs, damsel bugs and lacewings.

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