Large Numbers of Bagworms Found on All Sorts of Hosts

This insect is usually first detected by observing the larval bags made up of bits and pieces of host plant leaves and twigs that are woven together with silk. As the larvae grow and feed in the spring and summer, so do their bags. The bags can vary in length from ¼ to 2 inches. Many broadleaf and evergreen trees and shrubs can serve as hosts for bagworm species, including arborvitae and other ornamental conifers, cedar, cypress, elm, fruit and nut trees, juniper, oak, locust, maple, persimmon, pines, sycamore, willow and many other ornamental plants.
Although bagworm species vary slightly in habits and life cycle, the bagworm usually spends the winter months in the egg stage within the bag produced by the female from the previous fall. Very small larvae spin strands of silk and are carried by the wind onto other plants, or larger larvae can crawl to adjacent plants. Full grown caterpillars pupate within their bags usually in the late summer. The male moths emerge out of the bag. The male moths are black in color with ½ inch clear wings and feathery antennae. The male flies to mate with a female. The females remain inside their bags and do not have eyes, legs, mouthparts or antennae. After mating, the females produce between 500 to 1,000 eggs inside their bag and then die.
Infested plants develop more bagworms each year since the female stage does not fly. When there are large populations, the larvae can defoliate plants. Heavy infestations over several years, especially when added to other environmental stresses, can lead to plant death.

Some Control Options:

Non- Chemical Controls:
If only a few small trees or shrubs are infested, handpicking and destroying bags is recommended. During the winter months, the bags contain eggs and during the late spring and summer, the bags will contain a larva.


Chemical Control Options:
When many small bagworms, less than ½ inches are present, then it is recommended to treat with an insecticidal spray such as those containing acephate, azadiractin, spinosad, Bacillus thuringiensis var. kurstaki, permethrin, or bifenthrin.

Bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae), larval "bag" on arborvitae. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

Are Fuzzy Caterpillars Safe To Touch?

It is true, that it is not wise to pick up a fuzzy caterpillar with your bare hands! Usually if the caterpillar has hairs or is brightly colored, they can harm you. These features are meant to protect them from predators. If a predator such as a bird or lizard eats a fuzzy or brightly colored insect, it either tastes bad, gives the predator an upset stomach, or hurts the predator in some other way. This causes the predator to avoid eating another one in the future. Some fuzzy caterpillars such as the Woolly Bears and Tussock Moth Caterpillars have urticating hairs. These hairs can irritate the digestive tract of their predators, and can irritate your skin feeling like fine cactus needles. Puss caterpillars or Asps are more painful when touched. They are blonde in color and extremely hairy. These caterpillars have poison glands that produce an itchy skin rash when touched and hypersensitive individuals may require medical attention.

Puss caterpillar or "asp", Megalopyge opercularis (J. E. Smith) (Lepidoptera: Megalopygidae). Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

What Is Making You Itch This Summer?

As we enjoy the warm outdoors, we need to protect ourselves from a small red mite, also know as a chigger. Chiggers develop through four lifestages: egg, larva, nymph and adult. Six-legged larvae hatch from the eggs and climb up onto vegetation, so they can crawl onto a passing host. This is the only stage that feeds on humans and animals. Chigger larvae prefer to bite people in places where clothing fits tightly over the skin such as around the waistline, under socks, or where the skin is thin or creased such as around the ankles or the back of knees. Chigger larvae insert their mouthparts into a skin pore or hair follicle, and then inject a digestive fluid to dissolve skin cells. This results in itchy, reddish welts on the skin. After feeding, the larvae drop off of the host to molt into eight-legged nymphs which then molt into adults. Chigger nymphs and adults feed on eggs of springtails, isopods, and mosquitoes. Under favorable conditions, most chiggers complete their development from egg to adult in 40 to 70 days.

Suggestions for Prevention:
Avoid sitting on the ground when camping, picnicking, or working outdoors. Wear tightly woven socks, long pants, long sleeved shirts, and high shoes. Also tuck pant legs inside boots and button cuffs and collars as tightly as possible to prevent chiggers from climbing inside your clothes. Apply repellents such as DEET or permethrin to both the skin and clothing. Powdered sulfur is another repellent that can be dusted around the opening of your pants, socks, and boots or rubbed on skin such as over legs, arms and waist.

Suggestions for relief after exposure to chiggers:
Wash clothes in hot, soapy water to kill chigger larvae. Take a hot bath or shower and soap repeatedly after chigger exposure. Creams or ointments such as hydrocortisone or calamine lotion can be applied to relieve itching temporarily.

Suggestions for Use of Insecticides:
Chiggers sometimes become a problem in home lawns, so chemical control may be desirable. Insecticide sprays may provide some temporary reduction of chiggers and they are effective when applied in areas where chiggers and their animal hosts are living and/or roaming. Insecticides containing carbaryl, permethrin, cyfluthrin are some suggestions for control.

Photo of chigger bites. Photo by Michael Merchant, Professor and Extension Entomologist, Texas A&M University.

Attack of the Yucca Bugs

This year you many have noticed abundant numbers of yucca bugs, Haticotoma spp. (Hemiptera: Miridae), if you have yucca in your landscape. The adults are about ¼ inches in length with a red head and pronotum and grayish-black wings. The yucca bugs are usually found in large groups on the upper leaf surface and will tend to move quickly when disturbed. The immature stage or nymphal stage (those without wings), will also be present on the leaves. The yucca bugs have piercing sucking mouthparts so their feeding causes small pale spots or blotches on leaf surfaces where the green chlorophyll has been removed.
Some control options for the immature stage include insecticidal soap or pyrethrins. Systemic insecticide products, such as those containing acephate, dinotefuran or imidacloprid, are also effective for control of these bugs.

Haticotoma (Hemiptera: Miridae) species on yucca. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

Possible New Scale Found on Crape Myrtles in North Texas

This bark scale in the genus Eriococcus, is thought to be an exotic insect pest that has infested North Texas crape myrtles. These bark scales appear as white, waxy encrustations near pruning wounds or in branch crotches. Larger female scales “bleed” a pink liquid when crushed. Since this scale excretes honeydew, the limbs and leaves become sticky. In heavy infestations, black sooty mold will begin to grow on the truck and branches of the crape myrtle.
Currently, the crape myrtle bark scale has only been observed infesting crape myrtles in north Texas area (from South Dallas to Sherman). If you live outside this area and believe you have an infestation of this scale, please submit your sample or a picture of the infested crape myrtle to your local county Extension office or to Dr. Mike Merchant (m-merchant@tamu.edu) or myself (k-schofield@tamu.edu) at the Texas AgriLife Research and Extension Center, 17360 Coit Road, Dallas, TX 75252.

Some Control Options:

For heavily infested crape myrtles, it is recommended to wash the trunk and limbs with a soft brush and dishwashing soap solution to remove female scales and egg masses. Also, washing with the soapy water will remove some of the black mold.
Systemic insecticides such as those containing imidacloprid or dinotefuran as a drench applied to the root zone have shown good control when applied between the months of May and July. Also winter applications of dormant oil to the bark and crotches of the plants where scales shelter is an effective control option.

Spring Weather Means Attack of the Aphids!

Aphids are small, soft-bodied winged or wingless insects about 1/25 to 1/8 inches in length, with relatively long legs and antennae. Aphids can vary in color from black, green, yellow to even pink. Some aphids lay eggs, while others give birth to live young that can mature in as little as 7 to 8 days. Aphids have piercing-sucking mouthparts that remove phloem from the plant, which can cause distortions in young leaves and stunt new growth. They can also feed on flower buds, which cause deformities.
Since aphids feed on phloem they excrete honeydew, which is a sticky waste product that collects onto lower lying leaves. Once deposited, the honeydew is a nice food source for sooty mold which may grow on the underlying foliage. Sooty mold will inhibit photosynthesis, so its growth can potentially cause severe harm to the plants.

Some Control Options

Some Non-Chemical Control Options: Conserve beneficial insects, such as spiders, praying mantids, assassin bugs, lacewings, ladybird beetle larvae and adults and parasitic wasps in outdoor landscapes. Also spraying water streams is effective to dislodge aphids feeding on plants.

Some Chemical Control Options: Insecticidal soaps and oils can be used to control aphids and are considered low impact insecticides. Other foliar insecticides containing such active ingredients as permethrin, cyfluthrin, carbaryl, deltamethrin, pyrethrins and tebufenozide or systemic insecticides such as those containing imidacloprid or acephate can also be used.

Yellow sugarcane aphid, Sipha flava (Forbes) (Homoptera: Aphididae). Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

Time to Treat for Fire Ants

Red imported fire ants, Solenopsis invicta Buren, are an invasive species that has infested over 360 million acres in the southern United States, and they are continuing to spread. Fire ants are aggressive ants and within seconds after being disturbed, will begin to bite and sting. The fire ant workers bite first and then sting repeatedly, since they have a smooth stinger. After the first sting, it can rotate its stinger and sting again, leaving a circular pattern of stings. Most people who are not highly allergic develop welts and pustules. Fire ant stings can be fatal to those who are severely allergic. Symptoms of a severe allergic reactions include excessive swelling, shortness of breath, and thickening of the tongue. Those who are severely allergic to fire ant stings should seek medical attention immediately.
The use of chemicals is needed to manage their populations, in order to allow the native ant species back into the landscape. Fire ant baits, drenches, dusts and contact granular insecticides may be applied to control fire ants. It is advised to treat the individual fire ant mounds directly if less than 5 mounds are found within a 1/4 acre or less than 20 mounds within 1 acre, since this is not considered an infestation. However, if more than 5 mounds are present within a ¼ acre or 20 mounds within an acre, then a fire ant bait or contact insecticide should be broadcasted over the entire infested area. Fire ant baits are made up of defatted corn grit covered with insecticide and soybean oil. Before broadcasting the fire ant bait, foraging activity should be assessed, by placing a potato chip or hot dog next to the mound. If fire ants find the chip or hot dog within twenty minutes, then it is a suitable time to broadcast the bait. Fire ants will typically actively forage when the soil surface temperature is between 70 and 90° F, which is between May and September. Fire ant baits should never be watered into the soil and they should not be applied if they smell rancid. On the other hand, contact granular insecticides can also be broadcasted over the entire infested area and need to be watered into the soil. Control using contact granular insecticide generally lasts for 6 to 12 months, depending on the active ingredient within the insecticide.
Both fire ant baits and contact insecticides can be broadcasted using a hand-held spreader for small areas or a Herd Seeder can be mounted onto a truck or ATV for larger areas.
For more information, please visit the fire ant webpage at http://fireant.tamu.edu.

Aftermath of many fire ant stings!

Fire ants stinging in a circular pattern.