Hunt County Master GardenersTexas A&M AgriLife Extension Service

The Bane of Bag Worms

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The Bane of Bag Worms by Pat Newell

Although bag worms are not abundant every year, once a plant is infested it can become a persistent problem. If an infestation is left unchecked they can defoliate and kill trees and shrubs.        I learned an important lesson while researching this information. As an example of using individual’s sites for research, my initial search said that bagworms turn into web worms. When I went to several University Extension sites that turned out not to be true. Bagworms and webworms are two entirely different insects. Bagworms look like small shaggy Christmas ornaments, or tiny pinecones, about 2 inches long. Once you know what to look for they are easily visable in winter.  Normally they are in Evergreens, and Sweet Gum trees, but any plant may be susceptible, such as Oaks, Pecans, and fruit trees.

Eggs hatch in the bags in spring, the larvae, or caterpillars, then emerge, and fall to the ground. They then go back up into the plant where they eat leaves and make new bags, or enlarge the existing bags, as they grow. In September the caterpillar pupates, or turns in the moth. The winged males mate with the females, who then lay the eggs in the bag, dies, and the eggs over winter in the bags. If this cycle can be interrupted at any stage the problem disappears.

Interrupting the cycle, however, may be easier said than done. If the bags are in small, or short, plants, hand picking the bags is the most reliable treatment. You will notice as silken thread that holds the bag to the tree. If possible remove the thread as well, since it can choke the twig it is on.  It is important not to throw the bags on the ground, since this does not interrupt the cycle. The larvae can hatch on the ground as easily as on the tree. Placing them into a ziplock bag, sealing it and putting it in the trash is the best method of disposal. Unfortunately many of the trees have bags that are too high to reach, even with a rake to pull down the branch. If the tree is badly infested, and is worth the cost, professionals can be brought in the handle the problem.

Since a professional spraying into a 40 foot tree is beyond the means of many of us, several other methods have been suggested in various University Extension sites. The most important thing about treatment, even before knowing what to do, is timing it to be most effective. If you are able to reach any of the bags, put them in a dark place. I use a can with a good lid. In spring open the can frequently so that the larvae can be seen as they hatch. This is the best time to treat the caterpillar problem, while the larvae are small and feeding. Various insecticides are recommended at this stage, the easiest being a soil application of Dinote Furan, or even the reliable Seven dust around the base of the tree. Since the caterpillar has to climb back up the tree to feed, one very respected Extension site even recommended a bird feeder near the base of the tree, or spreading seed around the base of the tree for ground feeding birds.

The Fall, while the bags are still small, is the best time to use the various sprays that can penetrate the still thin walled bag. BTK, Malathion, Neem oil, Spectracide Bug Stop have been proven to do the job.

Seeing all those bags hanging can look like a problem that can’t be controlled, but timing, insecticides, and even some old time basics can get rid of the shaggy, deadly, Christmas ornament looking bags that can destroy our trees.

Squash Bugs

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If you have cucumbers, squash, pumpkins, or melons, you have likely encountered squash bugs on your plants.  These flat, large insects are about 5/8 inch long and 1/3 inch wide.  They are usually dark brown to dark gray and have a diamond shaped shield on their shoulders.  Their abdomens protrude and are typically orange and brown striped.

The eggs of the squash bug are oval, small, and yellowish to bronze.  The nymphs, or babies, go through five stages of growth, or instars, and are green when born.  They gradually get darker as they mature.

Squash bugs pierce the leaves of your plants and suck the juice out of them.  This causes yellow spots that eventually die and turn brown.  It also deprives the plant of some of its water and nutrients, which can cause the plant to wilt.  Young plants may die from a heavy infestation of squash bugs.  Older plants are better able to tolerate the damage, but can also die if the infestation is very heavy.

Squash bugs can be controlled with cultural, physical, and insecticidal methods.  Cultural methods refer to keeping your plants as healthy as possible so that they can repel or survive an attack by squash bugs.   Physical refers to removing the nymphs and adults and dropping them in a pan of soapy water.  This kills the bugs.   This is particularly effective if only a few plants are effected or you have only a light infestation.

Placing a piece of cardboard in the rows between squash plants can act as a trap for the squash bugs.  They will hide under the cardboard at night and can be destroyed early in the morning.  Removing plant debris and other items squash bugs can hid in at night will help keep them to a minimum, as well.

Finally, if you cannot get rid of the squash bugs and they are inflicting significant damage on the plants, you can spray to control the bugs.  Squash bugs found early in the spring or summer need to be managed if there are a lot of them.  Squash bugs found late in the summer or fall have finished feeding and do not need to be controlled.

The best time to apply the insecticide is early in the morning or late in the evening, when bees and other beneficial insects are not active.  It is important to cover the undersides of the leaves with the insecticide, as that is where the bugs congregate.

Effective sprays for squash bugs are ones that contain the ingredients carbaryl, permethrin, bifenthrin, or esfenvalerate.  Be sure you read all package labels and only use the insecticide on plants mentioned on the label.

Butterflies

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Butterflies by Madeline Sullivan.

Watching butterflies gives you the opportunity to enjoy lovely weather and pretty areas.  Butterflies are at their best on calm, sunny days. In the southern states, some species fly all year round, but most of the time March to October is when you can observe large numbers of different butterflies.  Different species have different times of the year they are active, so walks in spring, midsummer, and fall will usually reveal different butterflies. Here in Hunt County, there are fields and prairies that have wildflowers in abundance, which are a main attraction for many species of butterflies. If you are an avid watcher of butterflies, you can visit different habitats and plant communities such as wetlands, bogs, dunes, woodlands, tundra, and chaparral, and each area will have its own species of butterflies.

If you would like to attract butterflies to your own yard, there are some things you can do to make your habitat inviting. First, you need nectar plants and host plants.  Butterflies drink nectar, so growing nectar-rich flowers will attract them to your garden.  Then, once the butterflies are in your garden, they need good host plants on which to lay their eggs, so that they become more prolific.  The eggs are often laid on the underside of leaves, and as the caterpillars go into the chrysalis or pupa stage, they usually hang from a twig and are often camouflaged. When caterpillars hatch from the eggs, they eat the foliage of the plant on which they were laid, and preferred host plants vary from species to species.  So, growing the right types of plants to feed the caterpillars is important.  Some good choices of plants for your butterfly garden are listed below.

Next, you should have water available.  To make a “puddler” for your butterflies, place some sand in a shallow dish and add water–just enough to make it very moist, and keep it moist at all times.  Another way to make a puddler is to have an open area in your garden in which you make an indention (hand or foot sized).  You will want to add some sand to it, keeping enough of the indention that it will hold a little water to keep the sand very moist.  The butterflies will appreciate a good drink from either kind of puddler.

When you water your plants, try not to water overhead if you can avoid it.  The overhead water dilutes nectar and washes away pollen.  Finally, it a good idea to have a nice rock or two in your garden, in full sun, so that the butterflies can perch and soak up radiated heat as they position their wings to get the maximum amount of sun.

Some plants for your butterfly garden:  Verbena, Parsley, Turks Cap, Roses, Lantana, Zinnias, Bee Balm, Purple Coneflower, Penta, Sage, Butterfly Weed and other milkweeds, Butterfly Bush and Brown Eyed Susan.

Fire Ants

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Fire Ants by PJ LaRue Smith

It’s a perfect day, you’ve got a glass of iced tea in one hand, lounging in your favorite

lawn chair, and all is well in your world. Suddenly, OUCH, OUCH, OUCH! Iced tea and chair

go flying in two different directions, and you’re up like a shot doing a wild slapping, stomping

dance. To anyone living in the southern US, the reason for this bizarre behavior is obvious – fire

ants!

The “imported red fire ant”, is the one most are familiar with in Texas. As the name

implies, these ants are imported, red, and will cause a burning sensation, much like a match on

the skin. Afterward (within 24 hours after being stung) a white pustule will form and the worst

part of the itching (which lasts for approximately three days) begins. Just as is the case for bee

and wasp stings, those who are particularly sensitive to the ant stings can suffer far more severe

reactions – anaphylactic shock and even death. According to a leaflet produced by the Texas

Allergy, Asthma and Immunology Society, “fire ants are the most common cause of allergic

reactions to stinging insects in Texas”; “Severe allergic reactions (anaphylaxis) occur in 1 – 6 %

of people stung by fire ants and occasionally these reactions may be fatal”.

Here are a few tips to avoid being stung:

  • TEACH children and visitors about fire ants and their hazard.
  • LOOK before you step, or put a chair, child seat, etc. for any sign of a mound (even a
  • small one) or foraging ant activity. If highly sensitive, place a light colored blanket, or tarp on
  • the ground before setting up the lawn chair. (This not only acts as a physical block, but also as a
  • visual aid.) When moving pots, look for surface disturbance of the soil, or mound activity at
  • drainage hole sites. It is prudent to tap the side of a pot a couple of times and watch for ant
  • activity – a clear sign that the pot should be treated before picking it up.
  • WEAR protected clothing. When working outside, wear boots, tuck pants inside
  • socks, and use gloves when working.
  • SPRAY insect repellents on clothing or footwear (these treatments can temporarily
  • discourage foraging ants).
  • CONTROL ants in areas used most frequently by people or pets.
  • AVOID high risk locations. Areas around trash containers, frequently used picnic
  • areas, spilled animal feed, due to the ready availability of food, are particularly attractive to fire
  • ants. If a large number of mounds are noted, exercise caution when choosing a place to sit – fire
  • ants often forage far from their mounds.

Due to worker ants using their jaws (mandibles) to gain leverage to sting, merely

jumping into water or running water across ants will not remove them. The best approach is to

knock them off briskly by hand (or a glove, cloth, etc.). If you are working in the garden and

suddenly find your gloves covered with fire ants – remove your gloves as quickly as possible and

slap any remaining ants off. (If, like myself, you fall into the 1-6 percentile of susceptible

individuals, do not be shy about divorcing yourself of fire ant covered clothing. Failure to do so

CAN become a matter of life and death.)

Texas A&M has an excellent website that covers medical treatment and control of

this bane to outdoor enjoyment at http://fireant.tamu.edu/.

Got Grubs?

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Got Grubs? by DeAnna Hambly

Dry wilted grass or areas where grass has disappeared completely could be signs of a grub infestation in the lawn. Another sign, holes in the soil, may indicate that crows or gophers are digging for grubs. Grubs are the most destructive insects to a lawn, and if left untreated they can destroy an entire lawn very quickly.

Grubs are the immature stage (larvae) of the adult beetle (Japanese, June or others). They are white or cream colored, have a C-shaped body and vary in length between 1/2 and 1-1/2 inches. Six legs and a brown head are distinguishing features. Grubs live two to three inches below the soil surface where they feast on the root systems of grasses and plants.

It is important to understand the lifecycle of this insect in order to eliminate and control it. The female beetle begins laying her eggs in the warm summer grass around mid July. The eggs hatch, and grubs are present in early August. It’s during this time that grubs are most destructive. They feed on grass roots; eating as much as possible in order to build up their body fat in preparation for overwintering, and they can quickly annihilate an entire root system.

In November the grubs go down four to eight inches into the soil to hibernate, and in the spring (March) they return to the top two inches of the soil and begin feeding again. The damage isn’t quite as destructive during the spring because larvae are not preparing their bodies for hibernation. Instead, they are preparing for the transformation into adulthood (pupation) which takes place in June. This period lasts about two weeks, after which the adult beetle emerges from the soil to begin the next round of mating, feeding and laying eggs.

It is relatively easy and inexpensive to control grubs if the correct treatment and proper timing are used. The ideal time to treat the lawn is during the larvae stage–early August through September. Grubs are young, small, and feeding close to the surface of the soil at this time. If your grub problem is severe, you may also need to apply treatment in the spring.

Grub control includes chemical, biological and preventative treatments. Chemical treatment requires the use of insecticides. Look for products that contain the words, “Season Long Grub Control”. You can treat your lawn for grubs as early as May, but it’s best to start in mid July.

In spring, use a 24-hour grub control application if necessary. Since most of the damage will be done in the fall, the goal at this time is to prevent the larvae from pupating. Both of the above products need to be watered into the soil before they are effective; be sure to read the application instructions for maximum benefit. Some chemicals are toxic to birds, animals and people. Please read all warning labels before beginning any type of chemical treatment around your home.

Biological control involves the use of Milky Spores. Milky Spore is a bacterial infection that infects white grubs. It does not infect other insects, earthworms, birds, animals, people or plants. This type of treatment is more expensive than using insecticides, and the results are not as rapid. However, treatment can last 15-20 years.

Preventative controls include maintaining well drained soil, thatching and aerating the lawn, and cutting your grass higher in the summer. You should also inspect your lawn in March and August for the presence of grubs. Cut a one-square-foot piece of sod, three to four inches deep. Roll it back, breaking up the soil to expose any grub activity. Do this in several areas of the lawn. An average of six or more grubs per square foot warrants treatment.

For more information on controlling grubs, visit the Texas A&M AgriLife Extension office at 2217 Washington Street in downtown Greenville.

Squash Bugs

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Squash Bugs by PJ LaRue Smith

A Texas vegetable garden usually contains several types of cucurbits – cucumber, squash/zucchini, cantaloupe, watermelon, pumpkin, and assorted gourds to name but a few.  Often-heard amongst gardeners in late spring/early summer is frustration over the “sudden” death that has befallen their squash plants.  In a row of plants, one will die, seemingly overnight, while the rest will carry on for a week or so before another suffers the same fate.

Many gardeners just attribute this to the hotter, drier weather, lack of rain, or simply a poor choice of variety.  While any of these might be responsible for plant death, the “squash bug” (Anasa tristis) is the likely culprit, especially in plants that seem to be thriving one day and wilted/dying the next. (Squash bugs enjoy munching on all members of the cucurbit family, however, their favorite meal is the squash plant – hence the name.)

Adult squash bugs are brownish gray to dark gray bugs about 5/8 inch long and will be the first of their kind to be seen.  Emerging in the spring, they mate as the plants begin to vine, laying yellowish to bronze-brown eggs in clusters on the underside of leaves, often in vine angles.  (Egg laying is not limited to just their host plant, as eggs can be found on tomatoes and even t-posts.)   When first hatched, nymphs have a green abdomen with crimson head, thorax, legs and antennae, later becoming grayish-white with nearly black legs and antennae.

Squash bug eggs hatch in one to two weeks, with nymphs feeding in clusters on the stems of the plant.  In six to eight weeks, they transform into adults which will continue to feed through the fall. Damage to the plants will show as a rapid wilting of the leaves which will then blacken, become crisp and dry.

Squash bug damage can be particularly detrimental to young, immature plants.  Many entomologists believe this is due to a highly toxic saliva that is secreted into the plant during feeding.  Without question, the amount of damage occurring on a plant is directly proportional to the density of squash bugs. While foliage tends to be the primary focus as a food source for the squash bug, the stems and fruit are also fed heavily upon.  Such intensity of feeding on a given plant can cause an entire plant, or section of plant, to die, while nearby plants remain healthy.

Squash bug adults are unusually difficult to kill with insecticides.  Adult control can be accomplished if the correct material is selected, however, it is more effective to target the nymphs.  A word of caution – cucurbit production requires pollinators, specifically, the honeybee – pesticide application while blooms are present should be done with extreme care.  Apply one that has little residual activity and do so only late in the day when there is minimal honeybee active in the garden.

The tendency of squash bugs to aggregate in sheltered locations can be used to advantage by the home gardener. Placing boards, large cabbage leaves, or other shelter for squash bugs induces them to congregate there during the day, simplifying there removal and disposal.

Eliminating crop debris in a timely manner is also very important. Squash bugs will often be found feeding on old fruit or in abandoned plantings, so clean cultivation is essential to reduce the overwintering population.  Good garden hygiene has been shown to be the easiest, most effective organic means of controlling this pest.

Southern Pine Beetle

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Southern Pine Beetle by Stephanie Suesan Smith Ph.D.

Ever notice lots of oozing wounds on your pine, cedar, or juniper tree? See rows of circular holes in the trunk? You have crossed paths with the Southern Pine Beetle. Now this may be good news if you want the cedar in your pasture to die, but if you happen to like the tree that is infected, you have a problem.

Pine Bark Beetle Damage

Pine Bark Beetle Damage

The Southern Pine Beetle is a type of bark beetle. It bores a hole in the bark of the tree and lays eggs there. When the eggs hatch, the grubs, or larvae, chew the wood around the hole they are in. The newly hatched ones eat the soft, inner bark. The older ones eat the harder outer bark.When it has grown enough, the grub pupates and changes into an adult. The adult chews a circular hole through the bark and flies off to find a mate.

The beetle kills trees by either girdling it or by simply sucking so much of the needed water and nutrients the tree starves. Often, the first time a homeowner sees a problem is when the crown of the tree turns yellowish, then red, and finally brown. By then, it is very difficult if not impossible to treat the problem.

Other signs that there is a problem are tubes of pitch, or resin, flowing from the tree. When first attacked by these beetles, trees often exude large quantities of pitch in an attempt to push the invaders out. Sometimes this works. Other times, it does not, or the tree is not able to mount this counter attack.In any case, such pitch tubes are signs of a problem and should be investigated further.

The beetles and their larvae are small, about 1/8 inch long. If you chip the bark off a suspected invasion site, you will see holes with tiny grubs in them. You may see the black adult beetles, as well.

If you have this problem, you will want to treat it promptly so other trees do not become infected. How you treat it depends on how severely the tree is infested and what symptoms it has developed. If the crown is brown, your tree is probably dying and should be cut down and burned as soon as it is cut to kill the larvae and beetles it contains.

If your tree is at the pitch tube stage, or the crown is still green, you may be able to save it. The district entomologist has had some success with using Bayer Advanced Tree and Shrub Insect Control. This is a drench you mix in a bucket and pour all around the tree. The tree takes up the drench as if it were water. When the larvae and beetles suck the sap from the tree, the poison kills them. Be sure to follow the label directions and be advised that this is not as successful with heavy infestations.