I was mowing my lawn last weekend, and when I trimmed up next to my azalea bushes I noticed a few bare spots in the foliage. Upon closer inspection, I found several azalea caterpillars munching away on the leaves. As I began to pick them off, I noticed many more young caterpillars searching for a meal and thought that it may be necessary for a pesticide application.
Azalea caterpillar moths are light brown with a 1 ¾” wing span. They arrive in our area in late spring, mate, and begin to lay up to 100 eggs on the underside of azalea leaves. The eggs hatch in August and the caterpillars emerge and begin to feed. Newly hatched caterpillars are yellow with black stripes and a red head, up to ¾” long. As the caterpillar continues to grow it becomes more of a black color with broken yellow stripes, red legs and a red head and can grow up to 1 1/2” long.
The easiest way to scout for these caterpillars is to look across the top of your azalea bushes for twigs with no leaves present in July and August. If you find this damage, dig around in the damaged area and you will be able to find the caterpillars chewing away on the foliage. If disturbed, the caterpillars will rear up in a “U” shape as if intending to sting, but don’t be alarmed. Azalea caterpillars do not have a stinger and can’t sting you.
The best way to control these pests are to pick them off and destroy them. You can also prune out branches that have clusters of caterpillars attached to the stems. For young caterpillars, you can treat with Bacillus thuringiensis (B.t) such as Green Light Worm Killer Concentrated, Safer Caterpillar Killer, American Grand Thuricide, and Bonide Thuricide. For adult caterpillars, you may need to use a more potent pesticide such as carbaryl (Sevin) or cyfluthrin (Bayer Advanced Garden Multi-Insect Killer). Apply the pesticide liberally to the foliage and wait. In a few days, the caterpillars will ingest the pesticide and fall from the plants.
As with all pesticides, read and follow all labels and directions when mixing and applying chemicals.
If you’d like to learn more about horticulture related topics, the Sampson County Cooperative Extension Service is offering the “Friends of Horticulture” program once a month. The next class will be on Thursday, Aug. 17 at 6 p.m.and Raised Bed Gardening is the topic. The location of the class is Sampson Extension Center, 93 Agriculture Place, Clinton. Registration is $5. Secure your spot in this class by calling 910-592-7161.
The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina State University nor discrimination against similar products or services not mentioned.
Brad Hardison is an Agricultural Extension Agent specializing in horticulture. Contact Brad by calling the Sampson County Extension Center at 910-592-7161 or by emailing [email protected]