A Who's Who of WDIs

Recently I received an inquiry from a Texas pest control company wanting to know if there was a list of official wood destroying insects (WDIs) in Texas. Since there are some specific instructions in state regulations governing WDI inspections, you would be excused for thinking that there might be an official list. But if there is, I can't find it.  If you go to the relevant section of the Texas Administrative Code, the rules say "The purpose of the [WDI] inspection is to provide a report regarding the absence or presence of wood destroying insects and conditions conducive to wood destroying insect infestation."  However, the rules don't specifically define what consists of a WDI.

So in lieu of any official list, here is my list of the important WDIs in Texas.  If you're from another state, the list is likely to be similar, although the relative importance of each of these pests varies from region to region.

Termite wings provide good diagnostic clues to the type of
termites infesting a home. Reticulitermes wings are smooth,
without hairs, and have two heavier veins along the leading
edge of the forewing.

• Subterranean termites (Reticulitermes species. Note: when the word "species" is written after the genus name, it refers to multiple different species within the genus). Knowing the exact species is not important for a professional doing an inspection, but keep in mind that there may be some differences (e.g., swarming times or potential for destruction) among the different termite species.  The most economically important termite species in Texas, and the U.S., is Reticulitermes flavipes, the eastern subterranean termite. These termites are called "subterranean" because they need contact with the soil, and almost always maintain their nest underground while foraging on both underground and above-ground wood.  Inspections should focus on looking for alates (swarmers) and the presence of mud tubes extending from the soil into the structure.  Alates can be confirmed as Reticulitermes by their forewings, which bear two strong, dark veins along the leading edge.  Wood damage from this and other Reticulitermes species consists of galleries chewed into the spring wood, following the growth rings. Also, because they are subterranean, gallery walls will be covered with specks of "mud", a combination of feces, saliva and soil.  



Formosan alate wings are covered with fine hairs, visible
under magnification.



Drywood termite wings are often dusky and have at least
three strong veins along the leading edge of the forewing.

• Formosan subterranean termites Coptotermes formosanus. This is an exotic termite species that has established in parts of Texas, but is also found in other parts of the South and in parts of California. One of the principal means of its spread appears to be via recycled railroad ties.  The Formosan termite belongs to the same family as Reticulitermes termites, and shares some of the same characteristics, including subterranean nests and mud spattered galleries; hence, it is also technically a "subterranean" termite. Identify Coptotermes by its nighttime swarming habits and its large, yellowish-colored alate.  The wing veination is similar to Reticulitermes, but the wing membranes are covered with fine hairs.  Workers are not easily distinguished from our other subterranean species, but soldiers have a teardrop-shaped head, contrasted with the rectangular head of Reticulitermes workers.  Galleries are similar to other subterranean termites, but Formosan termites produce "carton", a dense, honeycombed structure made from mud and wood pulp cemented together with saliva and feces.  
• Drywood termites (Cryptotermes and Incistitermes species) The so-called drywood termites are distinguished from subterranean termites by their above-ground nests and lack of contact with the soil. Because they live in wood, which usually has lower moisture content than soil, drywood termites are very efficient conservers of water. The most obvious sign of this skill are the fecal pellets they produce. Unlike the wet, smeared feces of subterranean termites, drywood feces are hard, dry pellets.  In the drywood termite rectum all water is squeezed from the feces by six rectal pads, leaving small (1/32 inch-long), six-sided pellets. Finding these pellets is hard proof of a drywood termite infestation. In addition, drywood termite galleries do not follow the grain of the wood, but may extend across multiple annual rings. Alates fly at night and have three strong, dark veins at the leading edge of the forewing. Drywood termites are most common in warm, high-humidity regions, such as the Gulf coastal areas, and parts of southern California.  They may be found in other parts of the country, however, when brought in on furniture or infested lumber. 

  

  Lyctid powderpost beetle adults (left) are distinguished from
  the common pantry pest, red flour beetle (right), by their
  round eyes and two-segmented antennae.  

• Lyctid powderpost beetles (family Bostrichidae, subfamily Lyctinae). These small, cylindrical beetles are usually brought into homes in infested hardwood trim or flooring, or in infested furniture. They are one of the most important WDIs in Texas. If you're not in the habit of looking carefully for signs of these beetles during a WDI inspection, you're opening your business up to a potential legal mess. The presence of these beetles in new homes has become highly litigious, as the owners look for someone to blame for their new, beetle-infested home. It's critical to look carefully at all hardwood trim, including wainscoting, baseboards, windowsills, cabinetry and wood flooring.  On horizontal floors or trim, sawdust usually accumulates in volcano-like piles surrounding the adult beetle emergence hole.  On vertical wood, small piles of very fine, almost silky, frass will accumulate on cabinets, edges or floors underneath the emergence hole. Adults can be distinguished from the similar-appearing red flour beetle by their darker color; globular, protruding eyes; 2-segmented antennal club and enlarged hind coxae.   



Carpenter ants are easily identified by their large size, single
node between abdomen and thorax, and smoothly rounded
thoracic profile.  Many Texas species are bi-colored, like this
specimen; but color alone can be misleading.

• Carpenter ants (Campanotus species). This insect is usually listed as a WDI; however in Texas carpenter ants are not very likely to do structural damage. They are more likely to occur in small colonies in wall voids and in insulation, but rarely as destroyers of sound wood. Some species of carpenter ant, like C. modoc and C. pennsylvanicus, are well-known wood destroyers, especially in the Pacific Northwest and in the northeastern states. They have given all carpenter ants a reputation as wood destroyers. For this reason, and because they are not difficult to report, I would recommend including carpenter ant evidence on a WDI inspection report.  The similarly-colored (but physically very different) acrobat ant, is not reported to eat or damage wood, therefore I would not report it as a WDI.  Carpenter ants are relatively easily identified by their large size, polymorphism (different sized workers in the same colony), single node and smooth curved thoracic profile. Inspectors should also be on the lookout for carpenter ant frass, which is the colony's trash dump.  Frass piles may include wood, insulation, dead insects, and sometimes pupal cases.  Any unusual debris piles that contain insect fragments are likely carpenter ants.



The old house borer is a medium-sized beetle (0.6 to 1 inch)
with two raised bumps and a mustache-shaped ridge on
the pronotum (shield behind head).

• Old House borer (Hylotrupes bajulus). The round-headed borer family, to which the old house borer (OHB) belongs, consists mostly of larger beetles with long antennae.  Most infest only dying or recently killed trees, so pose little long-term threat to a structure (although they may emerge from infested wood in the first year or so of a new home).  The OHB is an exception to the low-threat rule because of its ability to re-infest homes after its first emergence. Most infestations occur in homes up to 10 years old, but they can also infest and re-infest older homes.  According to Dr. Harry Moore, retired WDI expert from North Carolina State University, the OHB prefers wood with moisture content between 15 and 25%.  This moisture level is higher than normal in all but the more humid parts of the country.  Adult beetles are distinctive, emergence holes are oval in shape and 1/4 to 1/3 inch maximum diameter. Frass consists of very fine powder and tiny, elongate, blunt-ended pellets.  Infestations of OHB are most common in the humid Piedmont areas of the mid-Atlantic seaboard; however they can be found in homes throughout the eastern U.S.  Infestations are relatively rare in Texas.



Bostrichid beetles are mostly a minor WDI pest.  The rasp-like
pronotum and cylindrical body with abruptly angled wing
tips are characteristic of this family.

• Anobiid and other Bostrichid beetles.  Any emergence holes in structural wood or trim, of course, should be reported on a WDI report.  However, when the other pests listed above are ruled out, most of the remaining culprits will belong to miscellaneous species of anobiid (ANN oh BEE id) and bostrichid (boss STRICK id) beetles. Nationwide, anobiid beetles are the more important group.  These beetles feed on sapwood of both hard- and soft-woods.  They leave circular exit holes 1/16 to 1/8 inch in diameter, and produce a fine powdery frass with conspicuous pellets.  Adults of these beetles are relatives of the cigarette beetle and have a similar with a oval to cylindrical shape and downward pointing head, hidden from above.  Anobiid beetles thrive in wood with higher moisture content (15-30%) and probably for this reason, infestations in Texas are uncommon except in damp crawl spaces.  Some of the smaller holes bored by anobiid beetles may be confused with Lyctid powderpost beetles, but the frass is distinguished by the presence of rough pellets.
       Bostrichid beetles (with the exception of the Lyctid powderpost beetles) are generally incapable of re-infesting wood. Holes made by emerging adults are round and 3/32 to 9/32 inch in diameter.  Frass is tightly packed inside tunnels and tends to stick together.  Most bostrichid beetles have several rasp-like teeth on the front of the pronotum, presumably to aid in collecting and packing frass in the galleries.  One of the most common ways bostrichid beetles are introduced into homes is via wicker baskets and furniture.

Formosan termite swarming season

'Tis the season to be on the lookout for Formosan termite swarmers.  Over four seasons of monitoring Formosan termites in the Dallas area suggests that the north Texas swarming season ranges from mid-May to mid-June. Since 1999 my lab has documented Formosan termites from approximately 20 sites in north Texas.  Most of these sites seem to be associated with the transport and use of railroad cross-ties as landscaping timbers.

I am always glad to receive reports of suspected Formosan termites, but this year I am especially interested.   Our office, in cooperation with Dr. Roger Gold's lab in College Station, is contracting this summer with the Texas Department of Agriculture to map out active Formosan termites sites throughout Texas. To do this, we are returning to sites where we have previously collected this termite and placing out both light traps and ground monitoring stations. We want to do a better job of identifying infested areas, and (we hope) determine whether they have spread.

We need your help. If you know of any old or new sites (through specimens), would you consider calling us? Collection information we need includes: specific address, owner, owner’s phone and/or email, and dates and circumstances of collection (including whether the termites were collected indoors or outdoors). If you or your technician do find a new site, we would be very interested to know whether railroad crossties are located on or near the property, or whether the infestation can be traced to some other source.

Formosan termite swarmers (right) are larger and lighter in color than eastern subterranean termites (left). Winged reproductives can be distinguished from drywood termite swarmers by the 2 (instead of 3 or more) thickened veins in the leading edge of the forewings. Formosans fly at night, instead of during the day, like Reticulitermes. If you are in north Texas and see anything remotely like one of these termites, please let us know by calling 972-231-5362 and asking for me or Dr. Charlie Helpert. Any sightings from central, south, or coastal areas of the state should be reported to the Center for Urban and Industrial Entomology in College Station at 979-845-5855.  Any specimens collected should be placed in ethyl or rubbing alcohol as soon as possible.

As always, your help is greatly appreciated.

Also
If you don't have a copy of the PCT Field Guide for the Management of Structure-infesting Ants, now's a good time to get one.  The third edition just came out and at $9.95 it's a bargain.  I can't imagine being in pest control and not having a copy of this guide.  Check it out.

"If Kudzu wasn't bad enough"...and other thoughts on exotic pests

Dr. Dan Suiter and Lisa Ames with the University of Georgia just sent out a pest alert on an insect called the "bean plataspid". I had never heard of a plataspid (pla TASS pid) before, so I looked in my well-worn copy of "How to Know the True Bugs" by James Alexander Slater--a very useful book for relatives of the box elder bugs--but with no luck. A quick check of the Internet revealed that Plataspids are Old World insects--hence not covered by my U.S. field guide.

Suiter and Ames recently received numerous samples of these insects swarming around homes in Georgia. Homeowners there are being repelled by not only the numbers, but also by a foul smell associated with the bugs. Turns out that this was the first known collection of these insects, known scientifically as Megacopta cribraria in the U.S. It is native to India and China, where it feeds on kudzu.

At this point many Southerners can be heard shouting "Glory be! A bug that eats kudzu! An answer to our prayers!" If you are not from the South, or are unfamiliar with kudzu, it is an invasive plant nightmare. Originally introduced in 1876 at the Centennial Exposition in Philadelphia, Pennsylvania in a Japanese government display garden. Planted widely as an ornamental vine for its abundant vegetation and sweet-smelling flowers, it was promoted as a forage plant by the Soil Conservation Service in the 1920s and 30s for erosion control. Bad idea. Kudzu smother trees and other plants under a solid blanket of leaves, by girdling woody stems and tree trunks, and by breaking branches or uprooting entire trees and shrubs through the sheer force of its weight. It grows at a rate of up to a foot a day.

Unfortunately for us, the bean plataspid does not appear to be a good solution to kudzu. Besides being a household pest on the order of the box elder bug or the Asian mulicolored lady beetle, the bean plataspid is a pest of numerous legume crops, including soybeans. The University of Georgia, Georgia Department of Agriculture, and U.S. Department of Agriculture consider it a potential agricultural pest and are partnering to take some regulatory action.

This appears to be the latest assault against the native fauna in our country. It's bad enough to have a new structural pest stinking up our homes, but when a foreign insect crosses the border into the U.S. it's generally forever. The fire ant landed on the sandy bay shores of Mobile, Alabama about 80 years ago and forever altered the ecology of the southern pine forest to the Texas prairies. We still don't know the full impact of fire ants on native wildlife and plant life, not to mention the American economy.

Last week I attended a conference on invasive pests, put on by the Texas Invasive Plant and Pest Council, in San Antonio. If there was ever a more discouraging subject for a biologist, I don't know what it is. In one of the talks, a botanist talked about his efforts to catalog and classify all the invasive foreign plants in Texas. He proposed classifying certain plants as some pests as "super watch" plants. "Super watch" plants are those which might possibly be removed from the Texas landscape before they become impossible to control.

I think the concept is a useful one for insects. By classifying certain insects as "Potentially Eradicable" pests, or putting them on some sort of "Super Watch" list, we accept responsibility for going after these pests. It seems to me that under our current system we have little incentive to go after new pests before they can get established.

Take the Formosan termite. We continue to watch helplessly as this pest becomes established in new sites around the South and in Texas. The potential economic impact of the Formosan termite is staggering, as it is at least twice as destructive as our native subterranean termite on homes, and an eater of live trees as well.

Ironically this is one pest that, in my opinion, could be controlled in isolated infestations before it becomes firmly established. We have dozens of sites in Texas where the Formosan termite is established on one or a few home properties. A determined effort to eradicate colonies with termite baits has, in my opinion, a good chance of succeeding in nipping many of these mini-invasions in the bud.

So what does all this have to do with pest management professionals? Knowing where a pest is found and how fast it is spreading is important for decision makers to know whether and how an invasive pest might be eradicated. Suiter and Ames are requesting PMPs in Georgia to report any sightings of the bean plataspid there. Here in Texas we are requesting PMPs to report new sightings of the rasberry crazy ant and the Formosan termite. These reports are very important to us and often form the basis for research dollars to work on solutions for these pests.

I will be working with Drs. Roger Gold and Robert Puckett this year attempting to delineate precisely where Formosan termites are present in the state of Texas. The research is being funded by the Texas Department of Agriculture and USDA's Animal and Plant Health Inspection Service. More information about the project will be forthcoming, but if you know of any suspected Formosan termite infestations we definitely want to know.

If only the Formosan termite could be coaxed into preferring kudzu.

Mother's Day Termites

Historically in many parts of Texas and the South, Mother's Day marks the beginning of swarm season for Coptotermes formosanus, known in this country as the Formosan termite. And right on schedule I had my first Formosan termite report of the year yesterday, the day after Mother's day. In the process of working with the PMP who submitted the sample, I learned something that I believe is worth passing on.

When termites swarmers are reported from inside a home, the traditional diagnosis says that the house is infested and needs treatment by a termite control professional. When Wendell Daniel, of All Pest Solutions, brought in yesterday's sample it consisted of wingless Formosan termite swarmers. My diagnosis was that the home in question was likely infested and needed professional treatment, quick.

The problem was that this home had been treated before, in 2006; and a few Formosan swarmers had been found at the home annually since then. What made this especially puzzling was that only a few swarmers were found each year, and they were always de-alated (wingless-making diagnosis more difficult). The neighborhood where the home was located has a known population of Formosan termites. The homeowner has never seen any damage, and Mr. Daniels has never been able to detect any sign of activity at the home apart from a few indoor swarmers each year since 2006.

Puzzled, I called Dr. Rudi Scheffran at the University of Florida Research Center in Ft. Lauderdale--the termite capitol of the U.S. Besides being one of the leading termite experts in the country, Rudi is always willing to help and just one of the nicest guys to work with. After confirming with him that the termites I had were indeed Formosans, Rudi told me that even a first year colony in a home will typically launch a couple of hundred swarmers. Putting two and two together, we finally concluded that the termites being found indoors likely entered the home (accidentally) from outdoors, something that would rarely if ever be expected to happen with Reticulitermes, our native subterranean termites.

The reason an accidental indoor collection of Formosan termites is a more probable occurrence than for our local species is that Coptotermes are nocturnal. Being nocturnal they are highly attracted to outdoor lights. In our problem house the homeowner had gone in and out of the front door the night before, a streetlight (the only one on the street) is outside this home. The fact that the same pattern had occurred for four years in a row with no increase in swarmer number helped convince us that this home may not have been infested after all.

My lesson, at least with Formosan termites, is that I shouldn't jump to conclusions about an indoor infestation when one or a small number of swarmers are found indoors. As I thought about it, the very first record I have of Formosan termites in our area in 1999 came from a sharp-eyed homeowner who noted these large, suspicious looking winged insects on her kitchen window screen. These are not your ordinary termites, and the old rules don't all apply. It is not unusual for a nearby colony in a tree or railroad tie or other site to put out large numbers of termites. For several years we monitored swarms outside a north Texas home. It was not unusual for us to collect several gallons of termites in a week during swarming season.

Any termite swarming reports over these next few weeks should be checked out very carefully. Although Formosan termites are not common in Texas away from the upper Gulf coast, they have been reported from scattered sites throughout central, east and north Texas. If you find a suspicious or confirmed case of Formosan termites, please let me know. I do maintain a database of all known sites of Formosan infestation. As Dr. Scheffran so gloomily predicted yesterday, "in 50 years they will probably be all over". But in the meantime I'd like to know where they are, in case our state ever wakes up and determine to something about this very important new pest.