Brownwood News – The Brown County AgriLife Extension Office has been getting numerous calls concerning “trees being covered in hairy caterpillars”. In some cases, trees are developing bald spots. According to Brown County Extension Agent, Scott Anderson, the culprit is the Walnut Caterpillar which has emerged suddenly, partially due to the changing weather.
Often mistaken for webworms or army worms, the Walnut Caterpillar is 1 to 2 inches long, black with grayish lines that run the length of its body. They are also covered in soft white hairs. They don’t sting and are not poisonous. They feed on leaves of closely related trees such as pecan, walnut and hickory. Female moths lay large white eggs on the underside of leaflets in late Spring. The eggs hatch after nine days. Young larvae have a reddish brown appearance and feed only on the surface of the leaf and, as they grow older (20-25 days), they begin to consume the entire leaf.
In the event you want to take action, an insecticide can be sprayed. In order for the spray to be successful, it should contain spinosad or Bacillus Thuringiensis as an active ingredient. These insecticides are selective for caterpillars and are safe to humans. Keep in mind insecticide labels are always subject to change and the pesticide user is encouraged to read and carefully follow the labeled directions on the container.
Contact the Brown County Extension Office for more information at 325-646-0386.
