Sid Mullis: Red-headed azalea caterpillars return to area; cicada killers invade local home

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The red-headed azalea caterpillar is out early this year. I looked back in my files to see when I had written about them over the years, and it had always been in September or October.

Young red-headed azalea caterpillars cluster together when feeding, making it easier to control them.   SPECIAL
SPECIAL
Young red-headed azalea caterpillars cluster together when feeding, making it easier to control them.

Last Saturday, while working in my yard, I found them on several of my azaleas. They were feeding on just Indica azalea varieties (large leaf varieties such as Formosa). They seem to prefer them. Fortunately, I caught them while they were still young – some were barely large enough to be seen.

In addition to a red head, these caterpillars have reddish brown legs and a black body with rows of white or pale yellow spots.

The caterpillars cluster and feed together when they are young and disperse when they mature. Feeding together is a positive thing when it comes to control, as they will all be clustered together so you don’t have to go looking for them all over a plant.

Fortunately, the damage on my azaleas was minor. I got rid of mine by simply pruning the limbs they were on and throwing them in my yard waste container. You can also just pick them off and put them in a container with soapy water. If you don’t want to touch them, use a disposable glove.

For insecticide control, options include the organic Bacillus thuringiensis (Dipel or Thuricide) if the worms are less than ¾-inch long. When caterpillars are larger, you can use carbaryl (Sevin), various pyrethroids (all the insecticides that end in “thrin”) or acephate (Bonide Systemic Insect Control).

LAST WEEKEND, I got an e-mail and picture from a man who wanted to me to identify large insects in his house. He said he found several. The insects in question were cicada killers, and I told him that was the first time anyone had ever complained about them getting in a house.

Cicada killers are large, almost 2 inches long and black with yellow markings across their abdomen. They sport yellowish legs and dusky wings. Outside, these big insects usually ignore people. You will normally see the males patrolling around close to the ground in an intimidating fashion, but they cannot sting, so they are completely harmless. Females are rarely seen because they are busy hunting cicadas in the trees and must be provoked to sting. They use stingers to paralyze cicadas, the noisy insects that live in trees.

As big as female cicada killers are, they still have a hard time lumbering through the air with a cicada, so they often paralyze it, drop it from the tree, and then drag it along the ground.

Cicada killers are solitary wasps, unlike most other wasps such as hornets, yellow jackets and paper wasps that live in social groups. Cicada killers live in solitary units where each female digs her own burrow, 6 to 10 inches deep and as much as 6 inches horizontally, to lay her eggs. The nest entrance is usually left open. They prefer to burrow in well-drained or sandy soils.

Each burrow can have as many as 20 eggs, each in an individual cell, and each egg can have as many as three cicadas to feed on in its cell.

Cicada killer wasps are seen in the landscape in July or August for about a month. By September, adult cicada killers will have mated, provisioned their burrows with cicadas for the larvae, laid their eggs and died.

Although virtually harmless, cicada killers can invade your home landscape and make a mess with their dirt piles. If you feel control is necessary, locate their nests during daylight hours and treat after dark when female wasps are in their nests. Any over-the-counter insecticide will kill them.

Before you decide to do away with these insects, remember their name: They are cicada predators, so they provide good biological control of these pests of ornamental trees and shrubs. The best overall control is prevention. Because cicada killers nest in open areas without vegetation, healthy, thick lawns without bare spots will not be attacked.

If any get inside your home, check all the areas where insects can enter – thresholds under doors, around windows and in water or drain pipes.

REACH SID MULLIS, THE DIRECTOR OF THE UNIVERSITY OF GEORGIA EXTENSION SERVICE OFFICE FOR RICHMOND COUNTY, AT (706) 821-2349 OR SMULLIS@UGA.EDU.


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