As is the case with most infestations, early detection can be your best weapon. And an aphid infestation is no different. The most difficult aspect of aphid control is the fact that by the time you notice the damage, they have already taken control of a large part of the tree, and some might think it’s too late.
Aphid control is really a matter of early detection and prevention. Aphids cause the most damage in warm weather, usually with outside temperatures between 65° and 80°, and when plants and/or shrubs are coming out of dormancy and starting their growth season. One sure-fire way to know that you are dealing with an aphid problem is the notable sticky material building up on the leaves, often referred to as “honeydew”.
One crucial aspect of aphid control is knowing where to look. Aphids usually like to hang out on the underside of leaves, so it is important to make sure and turn leaves over to inspect them for signs of these intruders, including checking the newer growth on the plant. Another way of detecting aphids early is the appearance of their enemies, which include lady beetles and lacewings.
While early detection is critical for aphid control, don't forget that the best defense is a great offense. There are some simple things that you can do to keep an aphid infestation from happening in the first place. Spraying your shrubs and plants with water can help to knock any existing aphids off the leaves. This is effective because they have a very hard time getting back up to damage the plants as most aphids do not have wings. While not a permanent fix, regular spraying can disrupt the aphids enough to prevent them from causing major damage.
For large shrubs and trees, including those beautiful shade trees you park your car under to say cool, the most effective aphid control method is to perform preventative insecticide treatments that move through the tree systemically through what is referred to as systemic injections or tree injections. The injections are made of up special control materials that the trees absorb from the soil under their drip line and are transported by the sap all over the tree. The aphids then feed on the sap and ingest enough of the control material to stop them cold! Tree injections are perfectly safe and environmentally friendly, as the materials are not exposed to birds, pets or children at any time.