After a year of limited insect pest movement, probably drought related, damaging activity has recently been on the increase.

Calls and questions have not centered on just one pest, but a wide variety of worms, moths, ants, and flies.

However, the first report of Datana caterpillars feeding on live oak foliage was received late last week and this is a pest that can quickly become a problem if conditions are favorable.

These foliage feeders are often called oak leaf or live oak caterpillars in the Coastal Bend area.

At least two generations of Datana caterpillars appear in Kingsville each year.

Some years the pest is active every month except for a short period of time in the winter.

The caterpillars are easily identified.

They are hairy, black or grey in color, with white stripes running down the sides of their bodies. The hair is not dense but appears in tufts along the worm’s back.

Fully grown caterpillars can be up to two inches long and about as thick as a pencil. Not only do these pest defoliate trees, they also leave droppings on concrete walks and drives.

One reason that populations can develop so rapidly is the fact that the adult Datana moth lays up to 300 eggs in a mass.

Eggs are laid on the undersides of the leaves that will become the main course once the small worms hatch.

Caterpillars hatch from the eggs in about nine days and begin feeding. Young larvae feed only on soft tissue, leaving a skeletonized leaf behind, while older larvae feed on the entire leaf.

Like the fall armyworm, it is during the final larval stage that the majority of feeding damage occurs. Damage may be localized to just a branch or severe infestations can result in total defoliation.

The pest lives and feeds in groups and when they are disturbed, they tend to arch their heads and tails in a defensive posture.

Many times the caterpillars can be found high up in the tree and on the outer branches. They do move in a group to the tree trunk to molt from one stage to the next.

Many times they go unnoticed until they are spotted moving up and down the tree trunk. When they have neared the end of the larval stage and finished feeding, they drop to the ground and pupate in the soil.

Weekly inspection of oak tree foliage to detect feeding colonies will insure that populations do not build to damaging levels.

Control of this leaf eating pest can be achieved with common insecticides labeled for shade tree caterpillars. Good coverage is the key to successfully keeping the pest in check.