Flag waving for Americans

I never get tired of reminding PMPs that professionalism starts with good identification skills. One insect that is just rare enough to puzzle most pest control technicians is the ensign wasp.  It is also one of the odder insects found in homes and businesses.

The ensign wasp, Evania appendigaster may be one of the
oddest  looking insects in pest control. Its name comes from
the flag-shaped abdomen that it waves while searching
for its cockroach prey.

The ensign wasp is a quick and nervous little insect.  Black and 5-7 mm long, it is usually found one at a time. Though it might look intimidating with its quick actions and an abdomen bobbing up and down, it does not sting or bite.  It is, in fact, a beneficial parasite that helps control at least three household cockroaches, the American cockroach being the most common.

Ensign wasps are cockroach egg parasites. They are experts at locating cockroach egg cases (oothecae).  According to one account, when the female ensign wasp encounters a cockroach egg case, she first taps it with her antennae, presumably to confirm that it is an acceptable host for her egg.  Then she lies down beside it (I have never heard of an insect voluntarily lying on its side before!) and braces her legs against the ootheca.  After much labor she inserts her slender ovipositor into the tough ootheca and lays a single egg.  After hatching, the wasp larva matures while feeding on the dozen or more cockroach eggs inside each ootheca.  No cockroaches will hatch from an egg case that has been parasitized by an ensign wasp.

The name ensign wasp comes from the unique, stalked abdomen.  Shaped like a sailor's signal flag, the wasp frequently waves her abdomen up and down while stalking her prey as if to say, "Here I am!  Look out cockroaches!"

The oothecae of  American cockroaches are glued in out of
the way locations in walls, attics and other places. A single
egg inserted by an ensign wasp inside the ootheca will prevent
hatching.  Bugwood photo by Gary Alpert, Harvard Univ.

So what does it mean finding an ensign wasp in an account?  It means cockroaches are around. Not just any cockroaches, but one of the larger species of cockroaches (American, Smoky brown, or Oriental cockroaches).  I see one or two of these wasps in my office building every year.  I know they come from the rarely seen population of American cockroaches lurking in the walls and ceilings of our office building--something found in nearly every commercial building.  I like to think that we don't see a lot of cockroaches because we have these little wasps keeping watch.

Nevertheless if you or your customer are seeing these wasps on a regular basis, it might mean there are more cockroaches around than you suspect. Check the crawl space, attic and utility areas.  Make sure that p-traps in the floor drains are being filled with water on a regular basis.  Consider setting out sticky traps and baiting suspected harborage areas such as garages, attics, pantries or utility rooms.

If you are looking for more information to provide your customers about cockroach control, check out the Extension fact sheet Cockroaches and Their Control.

Concrete mites

Mites are among the tiniest arthropod pests to challenge the pest management professional. Tiny relatives of ticks (Class Acarina), mites play many roles in their microscopic world.  Some are predators of insects, insect eggs or other mites. Others are plant feeders, weakening plants and spreading disease.  Some mites feed exclusively on decaying plant material.  And still others are parasites, hitching rides on spiders or beetles, feeding on birds and mammals and even humans.

Insects are hard enough to identify because of their small size. But most insects are huge compared to mites. Larger mites may reach 1-2 mm in length; most are much smaller.  Scabies mite, one of the only mite parasites to exclusively feed on humans, are among the smallest of mites (0.18-0.45 mm-long) and visible only through magnification. Most mites are less than 1 mm-long, though velvet mites (the largest of the mites) can reach lengths of 4 mm, as long as a termite worker.

Clover mites are distinguished by their long front legs. Photo
by Rayanne Lehman.

For size reasons, I'll admit that I groan a little inwardly when I receive a mite specimen to identify. Mounting mites on glass slides is not one of my strong skills, and takes extra time.  So I was pleasantly surprised this week when a promised mite sample arrived and it was actually on the big size, at least for a mite.

I was initially ready to identify my client's mite as a clover mite, one of the common springtime mite pests in Texas. The clover mite, Bryobia praetiosa, is a reddish brown mite with very long pair of front legs, about 2X the length of the other legs. Though mostly harmless, the clover mite is an occasional nuisance pest indoors when it migrates from its normal feeding sites in grass and weeds outdoors through windows and under doors.  But there was something about these mites that didn't quite fit the clover mite profile.  

Balaustium (or concrete) mite. Photograph
by Lyle J. Buss, University of Florida

The one-millimeter-long, bright red mites were being found all over decorative stone and concrete in a Tyler, Texas backyard.  The homeowner thought he was being bitten, perhaps by mutant chiggers from you-know-where. But although chigger mites are also bright red, they are tiny (.3 mm) and barely visible to the naked eye. These were not chiggers.

An online search led me to one of my favorite online resources, Bugguide.net. There I discovered a mite genus I had never heard of before.  Concrete mites, Balaustium species, were a dead ringer for the specimens I had under the microscope.  So called, because certain species in this genus are commonly found wandering on concrete sidewalks, foundations and walls, and stonework, Balaustium mites are apparently common throughout the U.S.; but I had never heard of them before.

The University of Florida Entomology Circular Series (also an excellent source of detailed information about urban insects, especially plant-feeding pests) had a 1995 publication by W. C. Welbourn on Balaustium mites in Florida. According to the circular, at least one species of Balaustium is "commonly found in urban areas where they appear in large numbers on sidewalks and walls for a brief period during the spring and early summer. It is during this time that they sometimes enter homes and buildings and become pests."  

One of, if not the only, food source of these urban mites appears to be pollen. Balaustium mites have been found clustered in large numbers on anthers of flowers.  And based on the numbers of times I've had to wash my car and BBQ grill of oak pollen in the past month, I'm imaging that these mites have been having a good time of it lately.  This would also explain why the mites can be found on nearly any outdoor surface, including sidewalks and roofs--because pollen is everywhere.

Some species of Balaustium are predators on other insects, others feed on plants.  I was surprised, however, to read that there may be some association between our otherwise peaceful, pollen feeding, house-invading concrete mites and bites on people.  An entomologist named Irwin Newell in 1963 reported four cases of human "biting" involving Balaustium, three of which were associated with structures. The evidence for the bites was very strong, including a sample submitted by entomologist who was bitten on the arm while working in an entomology museum (how dare they!). 

The curious thing about the story is that while Dr. Newell stumbled across several cases in a relatively short period of time, prompting him to predict this mite was a growing problem, it's been crickets (silence) since then.  None of the major texts or reference books I scanned have even a mention of this family of mites, in spite of being common in the landscape. Even Ed Riley, Texas A&M University's crack assistant museum curator, was not familiar with these mites--though he admits, like me, to not paying too close attention to red mites he sees outdoors.  

Newell admits in his paper that he had no idea what species of Balaustium he was dealing with in his biting cases. And I don't believe anyone know what species are common in Texas. But I will be more interested and paying closer attention the next time I see my brick mailbox covered with red mites. 

[Request: I have little doubt that some of you get questions from customers about little red mites crawling on the sides of homes and sidewalks this time of year.  I would be interested to know if you or anyone you meet believes they have experienced bites from these little critters.] 

Spring caterpillars

Forest tent caterpillars can be recognized by their dark-
gray to brownish body color, with pale-blue and yellow lines
 extending along each side, and a chain of distinct,
whitish shoeprint-shaped spots running down the middle of
their back.

As every PMP knows, bluebonnets aren't the only thing that emerges each spring. The annual symphony of ringing phones in pest control offices this time of year is proof that insect activity returns with warm weather.  This year is shaping up to be an active year for caterpillars in Texas, so I thought that a review of some of the more common spring caterpillar pests might be appropriate.

Forest Tent Caterpillar 
Forest tent caterpillar, Malacosoma disstria, is one of the most widespread and abundant of the tent-making caterpillars in the U.S. Like its close cousins the eastern and western tent caterpillars, forest tent caterpillars feed primarily on trees; but unlike their cousins, and the also abundant fall webworm, the forest tent caterpillar doesn't make an actual tent. Instead it aggregates between feedings on a silken mat which is spun on some area of the trunk or on large branches of the host tree. After completing its larval development in two or three weeks, the caterpillar pupates and eventually turns into a handsome, but obscure, brown moth.

Forest tent caterpillars rest between feedings on a
silken mat where they may be easily seen
and treated.  Photo via NBCDFW Channel 5 TV.

Forest tent caterpillars appear but once a year, usually in April in Texas, and sometimes in very large numbers.  They then "disappear" for a whole year until the cycle begins again.  Some years caterpillar numbers are very high, but most years they may be noticed only by the sharpest-eyed observers.  The cycles of up and down appear to be driven by a combination of environmental and natural control factors, like birds and parasitic insects.  This may be one of those abundant years, at least for some areas of Texas. Sam Houston Electrical Cooperative reported dozens of power outages this month from masses of tent caterpillars covering electrical transformers, causing fuse overloads.  I have been receiving emails over the past few days from homeowners concerned about the caterpillars massed on their silken mats.

Spring Cankerworm

Spring cankerworm can defoliate entire trees and cover plants
and sidewalks with their webbing.  This tree is losing its leaves
as quickly as they can emerge.

Another caterpillar that can completely defoliate trees in the spring is the spring cankerworm, Paleacrita vernata. When cankerworm outbreaks occur, they can produce some of the most spectacular tree defoliation events seen in this part of the country. If you have a chance to walk through an infested forest you will see millions of tiny caterpillars hanging from tree branches and blowing on the wind. After a week or two of feeding, trees can be largely stripped of leaves. Fortunately, these outbreaks normally pose little danger to trees, especially trees in woodlots and forests. Healthy trees on good soil can usually withstand total defoliation without significant damage. Trees that lose their leaves to spring cankerworms generally re-leaf and show no signs of long-term damage. However, trees that are under stress from drought or transplantation may benefit from a timely insecticide application, before the leaves are stripped. This species also has only one generation per year, so late treatment of a tree with an insecticide, or follow up sprays, are not necessary.

Cankerworms belong to the moth family Geometridae. Spring cankerworms range in color from light green to brown. Like all geometrids, spring cankerworms have fewer than normal caterpillars. Where normal caterpillars have three to five abdominal feet, spring cankerworms have only two. The result is a distinctive looping walk, giving these caterpillars their common name "inchworm". Click here to see a video of this walk.

Eastern and Western Tent Caterpillars

Tent caterpillars make their nests in the crotches of trees in
the rose family.

The eastern and western species of tent caterpillars are in the same genus, Malacosoma, as the forest tent caterpillar.  The eastern tent caterpillar, Malacosoma americanum, feeds mostly on trees in the rose family, which includes most fruit trees (apples, cherries, plum, crabapple and hawthorn).  These species, however, go beyond silk mat construction and produce protective tents in branch crotches.  These tent caterpillars are common sight throughout the country.  In addition to chewing leaves, the tents themselves, when abundant, detract from the appearance of the trees in urban landscape settings especially.  Again, these caterpillars produce only one generation per year.

Fall Webworm

Fall webworm tents extend over the tips of
branches. Feeding then occurs inside the
tent.

Even though it is called the fall webworm, in Texas Hyphantrea cunea can be found throughout the growing season, starting in the spring.  Recorded from over 400 different species of trees, fall webworm webs are a common site both in cities and along rural roadsides.  Unlike the tent caterpillars, fall webworms live full-time within their webs.  As leaves from the tree are devoured, the webworm colony simply expands its web to cover new leaves.  Silk from tent caterpillar and fall webworm "nests" likely serve to protect the insects from bird and, to some extent, insect predation.  In some years whole trees can be stripped of leaves and become covered with the unsightly webbing.  Unlike the other tent-making caterpillars, fall webworms produce 3-4 generations per warm season, and may need repeated treatment.

Non-Chemical Control Options
With fall webworms and tent caterpillars, non-chemical control might include physical removal or destruction of the nest(s).  A pole pruner can be used to cut out webs from high branches, or it can be used to physically disrupt the nest and knock caterpillars from the tree.  This is only practical for early infestations restricted to a few nests or superficial branches.

To Treat or Not to Treat
Most trees can withstand significant leaf loss without any significant reduction in sugar production and storage (a measure of tree health). A rough rule of thumb is that 20% loss of foliage (for deciduous trees) should not be harmful to a tree.  Over 20% defoliation and trees may suffer slowed growth and stress.  An otherwise healthy tree can lose all its spring leaves and will re-leaf; however this does reduce vitality. Defoliation in combination with other stresses, such as root compaction, drought, disease, or other insect attack, can push a tree into decline or die back.  For this reason, it may sometimes be worthwhile to tree a tree for caterpillars.

Other reasons to treat a tree for caterpillars include aesthetics (preventing unsightly webs, or temporary leaf loss) or prevention of nuisance factors from droppings and caterpillars falling from trees.

Every customer faces a few decisions before having trees sprayed for caterpillars.

• Is the cost of the spray worth it for aesthetic options?  
• Is the tree in a location where it can be treated without drift falling into a swimming pool or neighbor's yard?  If drift is inevitable, can it be mitigated by covering the pool, or getting the neighbor's OK to proceed? 
• Can the spray treatment be done quickly enough to be worthwhile?  This is often the critical question, because most tree infestations are not noticed until caterpillars are nearly fully developed and the damage is mostly done.  

Chemical Control Options
If you and your customer determine that a spray is justified, you must determine the best active ingredient.  There are many options for caterpillar control. Spinosad and Bacillus thuringiensis are two of the better low-impact insecticides effective against caterpillars. However they are most effective against smaller caterpillars. Newer options include clothianidin (Arena®), chlorantraniliprole (Acelepryn™), and the combination product spinetoram+sulfoxaflor (Xxpire™). Pyrethroid insecticides are fast and tend to provide longer residual; however they are more toxic to non-target organisms such as beneficial insects. You should note that many of these products are toxic to bees and pollinators, so it is best to avoid spraying trees in bloom.

Lastly, it may be possible to save your customer some money and reduce drift potential and damage to beneficial insects through spot treatments. Forest tent caterpillar aggregations are easily spot-treated with a variety of insecticides including insecticidal soap and horticultural oil.  Likewise, individual nests of tent caterpillars or fall webworms can sometimes be spot treated even with a pump sprayer using a pinstream nozzle. Such applications, being very targeted, should control the caterpillars with little impact on other beneficial insects.

Pesticides not to blame for bee woes?

According to Science Daily, new research shows that imidacloprid, an insecticide often blamed for the decline of commercially managed honey bees, is not likely to harm honey bees at field realistic levels.  The three year study, conducted by Galen Dively and associates at the University of Maryland, supports the contention by many U.S. bee researchers that proper applications of this insecticide is not likely to be the sole, or major, explanation for colony collapse disorder (CCD).

New labeling for some plants
sold by The Home Depot alerts the
consumer to neonicotinoid-treated
plants.

Despite those who claim CCD is clearly the result of dangerous insecticides, the issues surrounding CCD are complex and technical. Much of the debate in the research community recently has centered on what constitutes "field realistic levels" of imidacloprid and its cousin insecticides, the neonicotinoids. Industry representatives have contended that recent critical studies, cited by environmentalists as justifying a ban neonicotinoids, were flawed because they were based on unrealistically high levels of the insecticides. Dively and colleagues tried to allay these concerns by feeding their bees imidacloprid in protein supplement patties at doses of 5, 20, and 100 micrograms per kilogram (parts per billion).  The lowest dose, 5 parts per billion, is generally recognized as field realistic based on several studies of pesticide concentrations in the nectar and pollen of treated crops. The insecticide-laced protein supplement was provided to the bees over a continuous 12 week period. Even so this was, the authors contend, a higher exposure scenario than would likely occur in agricultural settings, where the contaminated pollen and nectar is not likely to be present continuously.

As one of the first studies to look at honey bee colony health over multiple seasons, the results were more rigorous than previous research.  They did showed a significant negative effect on colony survivorship as dosage increased; however the lowest, field-realistic dose showed no significant impact on key bee health indicators, foraging or winter survivorship.  The major impact of higher imidacloprid exposure were increased broodless periods, caused by weak queens during late summer. Such effects could lead to lowered overwintering survival, a character of CCD.

Nevertheless, the authors conclude that while short term exposure to high imidacloprid levels (represented by 100 part per billion dosages in this study) in agricultural settings does occur, it is not likely to occur continuously throughout a crop cycle.  Also, data from the study showed that bees were efficient in metabolizing imidacloprid, so that short term spikes in insecticide levels in nectar were likely to be quickly diluted and eliminated by the bees. They concluded that while imidacloprid might be a contributing factor to some overwintering losses in bees, seed treated crops in particular were likely to have negligible effects on honey bee colony health.

In the ongoing debate over bee health, this is one piece of good news for pesticide manufacturers and users; but it will not be the final word. And it should not justify anything less than the utmost caution for pesticide applicators when they use neonicotinoid insecticides.

Get updated on fire ant baiting

Fire ants remain the most prevalent outdoor ant pest in most areas of the southern U.S.  Throughout the U.S. we estimate the annual cost of fire ant control at over $6 billion.  But the cost of this pest goes far beyond measurable dollars.  Fire ants reduce the recreational value of our parks and backyards, disrupt wildlife populations, and send thousands to emergency rooms each year from their painful stings.  

So as we get ready to enter fire ant season, it may be a good time to bring yourself and your staff up to speed on fire ant control. Many people are surprised to learn that fire ants are not an especially difficult pest to manage, once the biology and control tools are understood.

One of the best places to learn about fire ant management is the E-xtension fire ant website, a place where the best information about fire ant is assembled by Extension agencies throughout the South. This information was recently summarized and presented in an informative webinar by Dr. Fudd Graham, fire ant specialist with Auburn University.   Dr. Graham focuses on fire ant biology and use of baits for fire ant control.

It's worth knowing something about how fire ant baits work because they are the most economical, ecologically friendly, and effective control methods for fire ants. The webinar will provide you or your technician with an hour of training that should pay for itself many times over.  

Winter Structural Pest Control Advisory Committee meeting

It was a cold, wet day in Austin this week as the Structural Pest Control Advisory Committee met to discuss the business of pest control regulation in Texas. Much of the meeting was going over rules drafted by the SPCS staff that will impact just about anyone who does structural fumigation, provides termite estimates, or who want to get continuing education units online.

Mike Kelly, staff member for the Structural Pest Control Service (SPCS), presented a rough draft of new document requirements for termite treatment disclosures, or as they are now called: "Subterranean Termite, Drywood Termite and Related Wood Destroying Insect Treatment Disclosure Documents" (The new name may be good for clarity, but sometimes I think government rules eat as much wood--in the form of paper--as termites).  Most of the changes are minor, designed to make the regs easier to read; however one positive significant change is that written estimates using these documents will now have to be made by a licensed technician or Certified Applicator--not an unlicensed sales person or office staffer.

Following up on industry recommendations from last meeting, Kelly also presented proposed changes for Structural Fumigation Requirements.  To anyone who is not a fumigator, fumigation requirements are about as exciting as a wait at the DMV.  But to fumigators, any change in rules can be grounds for fightin'.  Acting on our last meeting's discussion, the biggest changes to the rules included an attempt to clarify the responsibilities of fumigation contractors and subcontractors.

Danielle Dean (right) and Betty Thornton explained the new
CEU course they have developed for pest control office
managers and staff. 

Now if it were up to me, I'm not sure I would let anyone subcontract fumigation jobs. Fumigation is risky and technically complicated, and way too many things can go wrong (communications wise) between the customer and the subcontractor(s) who actually does the work.  But that's not the law, so these new rules attempt to reduce the risk of misunderstanding between fumigator and customer. As you might guess, there will be more paperwork.

One proposed rule change specified that only a registered apprentice, licensed technician or certified applicator (CA) can assist the supervising CA with introducing fumigants, or performing reentry and aeration activities. Also Kelly proposed to clarify wording on the required condition of tarps used in sealing in fumigant gases, and what the official time for a start of fumigation should be based on.  Both Brian Springer, Bevis Pest Control, and Debbie Aguirre, Elite Exterminating, commented passionately on the requirements--Springer noting the stellar human safety record of structural fumigation in Texas in recent years.  If you have anything to do with fumigation in Texas, you'll want to review these new regs carefully when they come out this spring. None of the rules are official until you get a chance to review them, and if you're a fumigator I'm sure you'll have an opinion.

We also discussed online CEU courses as supplements or replacements for face-to-face training. There have been numerous proposals over the years to allow applicators to get training remotely; but concerns about accountability, quality of courses, and security have slowed approval of this option.  The committee heard from AgriLife Communications specialist Holly Jarvis and representatives from online training provider, eStrategy Solutions.  According to Jarvis, there are now multiple ways to make these courses interactive, and accountability can be even better than live courses. Committee members felt that it was time to make electronic courses a routine way for license holders to get the CEUs they need.  In addition to the convenience of getting training on any day you need it, online CEU courses allow the applicator a choice of training topics, including difficult-to-find CEUs, like fumigation.  We recommended eliminating the proposed restriction that online CEUs be allowed only every other year.  Such changes won't mean that CEU workshops with face-to-face training are going away anytime soon, but do they mean you'll have more choices when it comes to getting your CEUs.

The highlight of this month's meeting was a presentation by Betty Thornton, Alvin Pest Control, and Danielle Dean, bwi Companies.  Thornton and Dean met earlier in the year with staff at the SPCS to educate themselves about regulations that might affect office staffers at pest control companies. It turns out that a number of laws and rules limit what advice an unlicensed staffer can say to customers over the phone. An unlicensed person, for example, cannot diagnose a pest problem or offer price quotes to someone over the phone or via email. They took lessons-learned and developed a course for office staff and technicians that includes what you can and can't say over the phone, going paperless in a pest control office, role playing, how to get a new technician registered to take their license exam, how to survive a 14-point inspection, and avoiding the top 10 non-compliance issues.  Both Thorton and Dean were engaging and enthusiastic.  They have given their (approved CEU) course several times and are willing to go on the road for groups that want to sponsor them.

Office staff are a critical, and often neglected, segment of the pest control industry.  I commend the SPCS for their train-the-trainer efforts, and hope that all these efforts result in better trained office staff throughout the state. I think bringing office managers and staff into the training picture could turn out to be one of the single most significant things we can do to improve compliance with our pest control laws in Texas.

Perhaps not many of you make it to the end of these long reports.  But the last thing I want to say is that this meeting was very significant to me in that it marks the end of my appointment to the SPCS committee.  By completing the end of my second term I am required by another one of those dern rules to step down and let someone else get to drive to Austin four times a year.  I anticipate that my replacement will be Dr. Robert Puckett, our newly hired extension urban entomologist in College Station.  I know he is excited about the chance to serve and will do a great job representing Texas A&M AgriLife.  My thanks to all the faithful committee members who have served this committee on their own dime over the years, and to the TDA/SPCS staff who take the time to listen.  It's been a pleasure.

Bed bugs in China

A recent article published in the Journal of Medical Entomology by entomologists at South China Agricultural University caught my eye today. The study reported on bed bug infestation rates of homes in two south China cities.  While the results were not very detailed, they do give an interesting peek inside the world's most populous country with some of the world's most crowded cities.

The size of its cities, and the potential pest control market, in China is staggering. The combined population of the two cities in this study is 18.75 million (Texas population is about 27 million), and each of the two cities in the survey support approximately 1000 pest control companies (Texas supports about 3,000 companies statewide).

In addition to dense urban populations, city residents are highly mobile.  In one of the cities, the transient population (recent arrivals from the countryside and other cities) was estimated at 78%! Such conditions seem tailor-made for bed bugs, who are easily transported in luggage.  In addition, in the winter most of the population in the two cities simply vanishes into the countryside for the very important Spring Festival.

Surprisingly, until now the bed bug has not been reported as a major, widespread pest in China; though according to this survey, that may be changing.  A preliminary survey of 11 companies from the two cities estimated that 35% of all accounts being treated involved bed bugs. In examining the records of two medium to large sized pest control companies, 29-42% of all service visits involved bed bug infestations. In the largest city, Shenzhen, 91.1% of all rooms in apartments treated were infested with bed bugs, and 56% of workers quarters were treated for bed bugs.  In the neighboring city of Dongguan, 83.7% of serviced apartments had bed bugs, and 61% of worker quarters treated were infested.

By the way, China has double trouble with both the tropical bed bug, Cimex hemipterus, and the common bed bug, C. lectularius.

With its 1.3 billion citizens, China is a huge pest control market. The same with Mexico and other Latin American countries.  I've been thinking about this recently because the U.S. is hosting the International Congress on Entomology in 2016 in Orlando, FL. This will be the largest gathering of entomologists in the world, including top experts in urban and structural pest control.  It seems to me that PMPs as well as research and extension entomologists have a lot to learn about the way pest control is conducted in other countries. So if you are ready to learn more about your global partners in pest control, consider making a trip to the ICE in two years.