I noticed my car has been covered in a sticky substance the last two weeks. It’s parked underneath a Japanese maple tree, and it looks like the tree is infected with aphids. How can I get rid of them and prevent them in the future?
The sticky substance is called honeydew, and it is basically the tree sap that aphids — and other sucking insects — drink and excrete. Has this occurred in past years? This may be a particularly good year for them, and the problem may not be so bad in other years.
Since the tree is fairly small, I suggest starting with a strong spray of water. If you wash them off regularly, you can seriously minimize their population, not to mention washing off some of the honeydew. Inspect around the tree for ants going up and down it. In some cases, ants defend the aphids from predators so they can eat the sweet honeydew. If there are ants, use ant traps or bait to stop them from going up the tree.
There are, of course, insecticides you can use for aphids. Spraying a tree, even a small one, is difficult to control. There are systemic insecticides that can be applied to the soil, where they are taken up by the roots and thus eaten by the sucking insects. They can be very toxic to pollinators, though. If you choose to use an insecticide, read the label carefully and follow the instructions.
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Use pesticides safely!
- Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
- Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
- Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.
