Crapemyrtle Pests

Home Grown  by Keith Reed
Crapemyrtles are key plants for a colorful summer landscape in our part of the country. As marginally winter hardy plants, we never know for sure just how crapemyrtles will come back each spring until they have greened up. While we very rarely get winters that will completely kill the plant, we can get winter cold spells hard enough to cause them to die back to the ground on occasion.

Winter die-back certainly doesn’t seem to have been an issue this year, which is not unexpected since we had only two very brief cold snaps last winter. It’s actually quite the opposite with early green-up a common site around the area.

Early indications appear we are going to see some heavier-than-usual insect activity on some plants this year. Aphids are being seen in high numbers on crapemyrtles as well as a number of other spring landscape plants. Aphids are very small soft-bodied insects, usually but not always greenish in color, that accumulate in very high numbers on tender parts of plants. Aphids are considered sucking insects; they feed by piercing plant tissue and sucking the juices out.

In small numbers, aphids are not a problem. Most plants can get along just fine with low to even moderate pressure. However, if the numbers get very high, aphids can cause damage in two ways. The first is direct damage as already mentioned, by sucking vital plant juices out, causing wilt and decline. The second point of damage occurs when aphids exude honeydew, a sticky substance high in sugars. Honeydew is a favorite host to a dark fungal growth that can coat the leaves, leading to additional plant decline.

There are several ways to treat for aphids. In most cases, doing nothing is the best option as lady beetles and other beneficial insects will usually keep the problem under control. If you spot aphids and several lady beetles, do nothing.

If the plants are wilting badly, and beneficials are absent, control may be warranted. There are many products labeled for control so killing the insects is not a problem. The problem is aphids can quickly repopulate in very high numbers so it is important to keep a close eye on plants that are treated. Don’t assume the problem is solved. It is also important to realize that treating with an insecticide is also going to kill beneficial insects, and as these things go, the aphids will return quicker than the beneficials.

Another insect to keep an eye out for is the crapemyrtle scale, a tiny insect that works much the same way as the aphid, with a couple of exceptions. Scale attacks the stems of the plants, not the leaves. And, scale is much more difficult to control once it gains a foothold. Crapemyrtle scale is easily identified by the presence of very small cottony white spots. These white spots are actually the protective covering over the near-microscopic insect underneath.

Crapemyrtle scale is a new pest for us, and as of right now, there are not too many of them around. If you spot something you believe to be crapemyrtle scale, please contact me in the Extension office, and I’ll be happy to discuss controlling this pest in detail.

For more information of this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

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