High heat and humidity bringing pests out in full force

Published 12:00 am Thursday, July 21, 2011

High humidity and above average temperatures are causing some major problems for homeowners in Rowan County. Insects, diseases and other pests are beginning to show in force as the summer continues. Below are samples of questions that may be of interest.
Question: My neighbor has peony plants that are being eaten by these hungry caterpillars (the neighbor brought them into the office for identification). These insects have stripped the plants bare and I think they are going to kill them. What are these insects and how do I control them?
Answer: At first glance they appeared to be hickory horned devil larvae. These are large insects that feed mostly in the fall. Student volunteer for Cooperative Extension Taylor Bailey correctly identified the larvae as cecropia moth caterpillars. The cecropia moth, also known as the Robin moth, is one of our largest caterpillars that feed on wild cherry, plum, elderberry, maple, willow, apple, birch, lilac, walnut, pecan, elm, beech and poplar. The larva spins an overwintering cocoon attached to a twig on the plant where the larva fed.
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Question: I have a border of liriope that is inundated with bermuda grass. Is there a herbicide I can spray over the grass and kill the Bermuda grass and not harm the liriope?
Answer: Yes, according to weed scientists at N.C. State University, over the top herbicides that contain sethoxydim or fusilade as the active ingredient will kill the grassy weed and not injure your liriope. Be sure to read the instructions carefully. Some over the top sprays may require a spreader sticker or surfactant.
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Question: My tomato plants have these little white insects that are sucking the life out them (the grower brought the plants into the office). They are not flying and are very small. What are they and how do I control them without pesticides?
Answer: Your tomato plants are infested with aphids. There is no control without some type of insecticide. Insecticidal soap is a soft insecticide that will control the pest.
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Question: I planted some bedding plants in my flower beds and they are apparently being killed by voles. I thought voles only damaged hostas or nandenias. What is the best control for these pests?
Answer: Voles can be trapped with apple-baited mousetraps placed under the cover of flowerpots or other overhead cover that blocks out all light. Look for the tunnels or runs under the mulch, and place traps cross-wise to the direction of the runways. Continue to check traps at least once a week after the last vole is caught. An alternative control is to use a rodenticide such as Rozol.
Darrell Blackwelder is the county extension director with horticulture responsibilities with the N.C. Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970 or online at www.rowanextension.com