Spring is for pests

April showers may bring May flowers.  But they can also bring a wide variety of pests.  Two of the most common spring pests affecting school districts are termites and ants.

Swarming Termites and Ants

Over the past few weeks I have heard from several schools about termites swarms.  Believe it or not, termites that swarm are actually doing building maintenance a favor.

The one time of year that termites are most likely to alert people to their presence is swarming season.  Otherwise, termite damage can go undetected for a long time due to their secretive, underground habits.  Termites would do a lot more damage to buildings without evidence of the swarms because problems would go undetected and untreated for longer periods of time.

Termite swarming can start in January and February in South Texas and be as late as April and May up in the Panhandle.

IPM Coordinators should be familiar with the appearance and behavior of termite swarmers, and should encourage maintenance and custodial staff to report termite swarmers immediately.  Because swarmers disappear as quickly as they appear, it is too easy to assume the problem is also gone.  The presence of swarmers indoors is a sure sign of an active termite infestation that needs attention.

In most parts of Texas termite swarming activity starts with the construction of a swarm tube in late March or early April. A swarm tube looks innocent enough at initial formation – a small dab of mud or dirt appearing mysteriously on an indoor wall.  Within a week or two, however, when the weather conditions are right, the tiny hole becomes a doorway for dozens to thousands of termite swarmers.

Fortunately, the thousands of termite swarmers emerging into a school office or classroom are not likely to contribute to the indoor spread of termites.  Subterranean termite swarmers that emerge indoors are unlikely to start a new colony.  Because they cannot reach soil, swarmers that emerge indoors usually die quickly.

The presence of swarmers in a building is a pretty good indication that an active termite colony is in the building.  You should call in a pest professional to conduct a thorough inspection and treatment.  In the meantime, if necessary termite swarmers can be removed from the swarming area with a HEPA vacuum and the point where swarmers emerge either sealed or treated with a small amount of pyrethrins spray, or other Green category product.  There are several treatment options to eliminate termite activity in a school or other building.  For more information about termite management, check out our Urban Entomology website.

Winged Ants Winged Termites
two pairs of wings, hind wings shorter two pairs of wings of equal size and shape
elbowed antennae hair-like antennae
narrow waist between abdomen and thorax no narrow waist

Spring is also the time for many of our nuisance ant species to swarm as well. Carpenter ants are among the largest ants found in Texas, making their swarms easy to spot and sometimes dramatic. There are fourteen species of carpenter ants that occur in Texas.

Common indoor species, Camponotus rasilis Wheeler and  C. sayi Emery, have workers that are dull red bodied with black abdomens. Worker ants range in size from 1/4 to 1/2-inch. They can be distinguished from most other large ant species because the top of the thorax is evenly rounded and bears no spines.

Carpenter ants usually nest in dead wood, either outdoors in old stumps and dead parts of trees and around homes (in fences, fire wood, etc.) or indoors (between wood shingles, in siding, beams, joists, fascia boards, etc.). Ant colonies are often located in cracks and crevices between structural timbers, but the ants can (rarely in Texas) tunnel into structural wood to form nesting galleries. When this occurs, Texas carpenter ants appear to prefer moist, decaying wood, or wood with previous rot or termite damage.  As a general rule, carpenter ants in Texas are not a serious threat to the structural integrity of a wooden building.  And unlike termites, they do not eat wood. Nests can sometimes be located by searching for piles of insulation, or sawdust mixed with insect fragments underneath sites being used by the ants as exit holes.

Fire ants

Another frequently seen spring insect is the red imported fire ant (Solenopsis invicta).  Fire ants are common in all southern U.S. states.  As the weather continues to warm, fire ant activity will also increase.  Initial imported fire ant mounds are found throughout the landscape and often near sidewalks or building foundations.  This is especially true in the cool spring because concrete tends to absorb and retain solar heat. These ants are aggressive and once encountered can result in stings, equipment failure and unsightly fields.

Despite the warm days with air temperatures in the 80s and 90s, soil temperatures are just climbing to levels where fire ants are foraging for food.  This means that in some areas it may still be a little early for applying fire ant bait.  Currently the soil temperatures ranged from mid-60s to the mid-70s here at the Dallas office.  Research indicates that fire ant foraging doesn’t begin in earnest until soil temperatures reach the 70 degree mark.  Our standard recommendation is to hold off bait applications until May.

While baits are still the most cost-effective and environmentally sensitive option for area-wide fire ant control, mound treatments are effective for controlling visible mounds and can be applied any time of year.  Mound treatments are ideally used against fire ant nests that need quick control, like mounds next to the school or in other inconvenient locations. For more information about fire ants and fire ant control, you can go to our Fire ant website or check out fire ant management plan.

Finally if you would like to confirm if your pest management professional is using a Green or Yellow category product, you can go to our Fact Sheet Recognizing Green Category Pesticides a fact sheet for how to ID Green products to learn more about Green Category choices.

By: Janet Hurley, Mike Merchant, PhD and Christopher Sansone, PhD, IPM Program Specialist and Professors and Extension Entomologists, respectively.

One Response

  1. Elbowed antennae is not a good discriminating characteristic. Many, if not most ant alates have non-elbowed antennae–females (gynes) have elbowed antennae and males do not, at least in the species I am familiar with (in the southeastern US). Numerically across populations, most ant alates are male, although the alate sex ratio in a particular colony is usually highly skewed (mostly males or mostly females).

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