Blackwelder column: Hickory horned devil is harmless

Published 12:00 am Friday, September 11, 2009

It was cool earlier this week; a sure sign fall is on the way. However, there are still days of warmth and even the possibility of more hot weather.
Any change in the weather often stimulates questions about gardening, especially with insect pests. Many have called with various questions concerning pests and other horticultural queries. Here are a few that may be of interest:
Q: I found this huge aqua-green caterpillar in my pecan trees. (This insect was brought into the office.) What is the insect and does it do any harm?
A: The caterpillar is a hickory horned devil, the larvae of Royal or Regal moth. These feed on a variety of trees such as oak, hickory, pecan, etc. These larvae do not do any significant damage. The larva does not sting, but does have a menacing facade. They are actually quite docile.
Q: Do I still have time to kill Bermuda grass before over-seeding?
A: Yes, maybe, depending on the weather. Bermuda grass grows best at very hot temperatures. When temperatures fall, the ability to eliminate the grass gets more difficult. Apply glyphosate (Roundup and others) as soon as possible for total root kill.
Q: I have some grapes that have a white substance all over the vines. It looks like somebody has spit all over the vines. Can I eat my grapes? Will this kill the vine?
A: Spittle bugs are what you have. They do little damage to the plant. These can be washed off with garden hose.
Q: I am over-seeding my lawn and will have some bare areas. You have spoken about putting down a mulch to conserve water. How much do I put down and what type?
A: Use clean wheat straw if possible. Put down about 1-2 bales per 1,000 square feet. Avoid putting down too much. You should be able to see the color of the soil underneath the straw. If you put too much, your seed will either fail to germinate or germinate weak. Some retail outlets sell a product that is made from paper and pressed into pellets. It expands with water and makes great mulch with no weeds. I have used it with great success.
Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. Call 704-216-8970