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When Your Trees Get All Sappy: How Aphids Feeding on Your Tree Make it Rain Honeydew

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If when the weather warms up in the coming spring and summer months your trees start raining on you, your car or your decking, your tree or trees could be infested with aphids. Despite their size, no more than 6mm in length, these tiny, slow-moving insects can secrete enough honeydew to leave your hair and clothes matted and sticky. Honeydew is what aphids produce (from their anus) after they have gorged themselves on tree sap. Obviously, tree sap is not something you want in your hair and clothes — or worse, on your car.

But why is it suddenly raining honeydew? Where did these critters come from? Many aphids — all of them female — hatch in the warmer months of spring. Others manage to survive, albeit in small numbers, camped out on plants and leafless trees as they wait for spring to arrive. Once spring arrives, the aphids' numbers multiply unimaginably. For instance, because all aphids born in spring and summer are females and can give birth to 5 new aphids per day for up to 30 days once matured, they can quickly infest a tree or plant.

Ants Ensure that Aphids Are Safe

Aphids spend their days with their suckers embedded in the leaves and stems of trees, drinking the sweet sap from within whilst continuing to reproduce. If a nearby ant colony discovers the presence of these aphids, a symbiotic relationship ensues. The ants protect the aphids and keep them docile and controllable via chemicals on their feet. In return, the ants get to enjoy the sweet honeydew produced by the aphids.

This is bad for two reasons. First, it means that your raining honeydew problem will only get worse. Second, because they are shielded from natural predators by the ants, the aphids can reproduce until they threaten the health of your tree. An infested tree's leaves will become yellowed and deformed, and some of its twigs and branches may even die as a result. Your only option then may be tree removal.

Act Quickly to Stem the Tide

As long as the weather is warm, your aphid problem is going to persist. If the numbers are so great that it is raining honeydew, then you need to take action now. Although aphids do have many natural enemies, they may be protected by ants. Call a tree service in your area and have them come out to spray your tree with pesticide. Spray-on treatments linger for several days, ensuring that any remaining aphids are eradicated from your tree.

If you can't park or stand under your tree without getting covered in honeydew, it's time you responded with a little rain of your own — the kind that contains insecticide!