Kimberly Schofield

Program Specialist-Urban IPM

k-schofield@tamu.edu

Fall Webworms

The fall webworm, Hyphantria cunea (Drury), is usually noticed when the light gray silk webs are discovered on trees in late summer and early fall. They are considered pests of shade and ornamental trees in urban areas, attacking more than 88 plants, when they enclose leaves and small branches with their webs. Four generations occur in the south Texas, with 2 to 3 generations occurring in northern Texas. The last generation in the fall is usually the most damaging.

The caterpillars build webs soon after hatching and they will remain inside the web consuming the tender parts of the leaves. If the caterpillars eat all of the leaves within the web, then new foliage will be enclosed within the webbing. The caterpillars are 1 inch in length, pale yellow or green in color, and covered with white and black tufts of long hair. The caterpillars will molt 6 or 7 times before dropping to the ground to pupate. The pupae overwinter and the adult moths emerge the following spring.

Some Control Options:

Some Non-Chemical Control Options:

1)Small webs can be removed by pruning and destroying the infested portions of branches.

2)A stick or pole can be used to snag individual webs to allow natural enemies such as yellow jackets, paper wasps, birds, and predatory stink bugs to consume the webworms.

3)Bacillus thuringiensis, B.t,. is effective against fall webworms if it is applied when the caterpillars are small. It is better to apply after the eggs hatch and the web is not so dense. Also spray surrounding leaves, since the B.t. coated leaves will also be eaten by the caterpillars.

Some Chemical Control Options: Chemicals should be applied after eggs hatch, since they are most effective on young caterpillars. Insecticides such as those containing spinosad and tebufenozide as active ingredients can be used. Multiple applications may need to be applied as generations occur.

Fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), web on pecan. Photo by Bart Drees, Texas A&M University.

Be on the Look-out for Bermudagrass Mites

The bermudagrass mite, Eriophyes cynodoniensis is a very tiny arachnid, about 1/125 inches in length. Bermudagrass is the only host for this mite and most damage occurs in coarser Bermudagrass varieties such as Common, Ormond, and St. Lucie. This mite is thought to be native to Australia, but now infests much of the southern United States.

Bermuda mites are creamy white in color. The female mites lay eggs under the leaf sheath. After the eggs hatch, they pass through two larval stages before molting into adults. They usually develop from egg to adult in 7-10 days, so large numbers of mites can develop in a short amount of time. All of the life stages can be found under the leaf sheath, and sometimes several hundred mites can be found under one leaf sheath! Unfortunately, these mites can disperse into new areas by the wind, other insects, or grass clippings.

This mite feeds under the leaf sheaths, which causes the grass to yellow and the leaf tips to twist. Then the internodes shorten and tissue swells, so tufts or a rosette appearance develops. The grass then loses its vigor, thins out and may die. The damage is usually worse in hot and dry weather. When an infestation exists, there is almost no green growth and the tufts become a mass of large knots that die. When this happens, weeds usually invade the area.

Some Control Options:

Non-Chemical Controls:

To manage small infestations, closely mow the grass to a height of 3/4 inches and dispose of all clippings. After mowing, water the turfgrass thoroughly. By keeping the turfgrass healthy, it will help the plants tolerate or outgrow an infestation.

Chemical Controls:

Chemicals such as trichlorfon, bifenthrin, deltamethrin can be used for control. When bermudagrass is treated with insecticides, it is important to apply a second treatment 7 to 10 days later. This second application controls the newly hatched mites.

Photo of Bermudagrass mite. Photo from Texas A&M University: http://aggie-turf.tamu.edu/aggieturf2/insect/images/bermudagrassmites.gif.

Another Ant Abounds

The dark rover ant, Brachymyrmex patagonicus, is causing great concern in many areas of Texas this year. This ant is believed to be native to South America, but it has now relocated and established itself in the southern United States. Outside rover ants may be seen running up and down on blades of grass, chairs, fence posts or any other objects in the yard very quickly.

The female swarmer ants (the winged ants) are 3/16 inches in length and brown in color. These swarmers will take flight just after dusk and are attracted to lights. The female swarmers are usually noticed the next day when a large number are floating in swimming pools. Their enlarged abdomen will appear to be striped. The male swarmers are very small compared to the female swarmers and some reports state that the males can fit through the tiny openings in mosquito screen. The worker ants can be more troublesome, since they can be found in a variety of indoor sites. These worker ants are 1/16 inches in length and are dark brown or reddish brown in color. For identification purposes, Brachymyrmex patagonicus have one node and 9 segmented antennae.
Rover ants are honeydew feeders, feeding on secretions from aphids, scales and other sap-feeding insects. Rover ants are commonly found in woods and other natural settings, as well as around buildings. Outside they will tend to nest in soil, mulch or other decaying wood. In buildings, they prefer areas with high moisture so they are usually found in bathrooms or where leaks occur in the plumbing.

Some Control Options:

The dark rover ant has a single queen within a colony but there can be many colonies in an area. This makes a large infestation within a building very hard to control.

Some Non-Chemical Control Options:

1) Find and seal small holes or cracks.

2) Treat nearby trees and shrubs to decrease the amount of sap feeding insects such as aphids and scales. This will reduce the amount of honeydew that can be consumed by the rover ants.

3) Prune limbs of trees and shrubs so that they do not touch the buildings. This will prevent easy access into the buildings.

Some Chemical Control Options:

Control can be found using a combination of baits and sprays. Some insecticidal sprays that can be used involve a combination of active ingredients such as those containing a pyrethroid and a neonicotinoid. Gel and liquid baits are also suggested to be used outdoors and indoors. This is a persistent ant so patience is needed for successful control.

Photo of Brachymyrmex patagonicus workers. Photo by AntWeb and Joe MacGown.

Field Crickets Abound

As we walk outside in the evening, a new sound might greet us. This new sound will be the male cricket’s mating song, which is a high-pitched sound produced by the male cricket rubbing its front wings together to attract a female. Their song can become an irritant to homeowners, since they live next to structures. Field crickets are normally an outdoor insect, usually found under rocks, logs or in any crack or crevice. However, they can sometimes enter our homes through doors and windows.

Crickets develop through simple metamorphosis, with an egg, nymph and adult stage. The female cricket will deposit eggs into the soil. Adult field crickets are ½ to 1 ¼ inches in length, black in color, and have a stout body. Several generations of crickets are produced every year.

Crickets feed on all organic matter, including decaying plant material and fungi. Since crickets breakdown plant materials, they are considered beneficial by renewing soil minerals. They are also a food source for many animals such as spiders, ground beetles, birds, lizards and small rodents.

Some Control Options:

Non-Chemical Suggestions:

1) Caulk or seal cracks and gaps that are found in the foundation, around doors, windows, and garage doors to prevent crickets from entering structures.

2) Trim weeds and tall grass growing near the foundation.

3) Remove firewood, brush, rotting wood, boxes, bricks, stones and other objects from around the structure, in order to reduce the number of harborage areas.

4) For crickets found inside the home, vacuum or sweep up and then discard them.

Chemical Control Suggestions:

If a severe infestation exists, there are granular products that can be used for control, such as those containing hydramethylnon. There are also chemicals that can be sprayed outdoors to provide a barrier around homes, such as those containing pyrethrins or bifenthrin. There are also products that can be applied in indoor and outdoor cracks and crevices, such as those containing boric acid.

A field cricket, Gryllus sp. (Orthoptera: Gryllidae). Photo by Dr. Bart Drees, Professor and Extension Entomologist, Texas A&M University.

Mention of commercial products is for educational purposes only and does not represent endorsement by Texas AgriLife Extension or The Texas A&M University System. Insecticide label registrations are subject to change, and changes may have occurred since this publication was printed. The pesticide user is always responsible for applying products in accordance with label directions. Always read and carefully follow the instructions on the container label.