An interesting story came out last month from the National Evolutionary Synthesis Center at U.C. Berkeley. The story does a nice job of explaining the connection between DDT and pyrethroid resistance, and why pyrethroid resistance has appeared to develop so quickly in the short time that bed bugs have re-emerged as an important North American pest (The one bone I have to pick with the story is its confusion of the relationship and terminology between pyrethrins and pyrethroids--there is no such term as "pyrethrums").
The answer is that when bed bugs reemerged this decade as a major pest they had already been "pre-selected" for resistance to pyrethroids by their previous exposure to DDT. Because DDT acts at a similar site in the nervous system as pyrethroids, researchers theorize that the same mutations that conferred resistance to DDT bestowed protection upon the bearers of those mutations from pyrethroids.
I remember John Osmun, one of my professors at Purdue University, recounting with excitement one of his early army adventures with bed bugs. As an entomologist with the military in the early 1940s he had been assigned to use a secret insecticide to treat bed bug infested army barracks. Almost miraculously, the long-persisting infestation was eradicated. The insecticide was, of course, DDT. Since WWII, DDT went on to become a widely used tool to manage many insect populations, including bed bugs. Unfortunately bed bugs have used their long experience with this insecticide to fight back against more advanced pesticides.
A recent study by Zhu et al (2010) looked at bed bugs collected from 97 locations in 17 states and found resistance to deltamethrin in 88% of the sites. Because of the scattered geographical sampling conducted in this study, the status of bed bug resistance in Texas is still tentative. The only sample from Texas collected and analyzed in this study was from Beaumont, and showed resistance based on one genetic mutation. Many of the samples revealed populations with another genetic mutation, or even two mutations. Relatively few populations sampled were classified as fully susceptible to deltamethrin.
This does not mean that resistant bed bugs cannot be killed with deltamethrin or similar products; but it does mean that the dose needed to kill will be greatly increased.
The research, especially the resistance maps of the U.S., should be considered tentative; but does give us a better idea why bed bugs are so difficult to control with standard pyrethroid insecticides. Even though the study focused on deltamethrin only, the results should be mostly applicable to all pyrethroids. Chlorfenapyr is the only other liquid residual insecticide that is widely used at the present time that is not a pyrethroid insecticide and to which bed bugs have no known resistance.
Monday, October 11, 2010
Friday, October 8, 2010
Fall Pest Management Seminar 2010
Hoarding and pest control
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| Part of a clutter rating chart in the Compulsive Hoarding and Acquiring Workbook. |
Allison Taisey is a project coordinator with the Northeast IPM Center in New York. She recently wrote about the hoarding problem on her new blog, IPM in Multifamily Housing. Allison has been working with multifamily housing for several years and assisted with a multifamily housing training that I wrote about last year. In her work she has encountered hoarding multiple times and has explored the connection between hoarding and IPM more than anyone I know.
Hoarding, she writes, is a complex disorder that involves problems with disorganization, collecting too many items, and developing an emotional attachment with those items that is hard to break. Hoarders cannot just "clean things up", at least not without help. Many people have been made aware of the hoarding issue through the A&E television program "Hoarders".
I encourage you to learn more about this difficult issue by visiting both Allison's and the A&E site. It's possible you may gain some insight into how to deal with the chronically cluttered apartments and homes you service. Any of you involved in servicing multifamily housing would likely benefit from subscribing to Allison's blog. And Allison, welcome to the world of pest control blogging!
Thursday, October 7, 2010
Snopes lists new bed bug email misinformation
“We have friends here in our community and one of their sons is an entomologist (insect expert), and has been telling them that there is an epidemic of bed bugs now occurring in America. Recently I have heard on the news that several stores in NYC have had to close due to bed bug problems, as well as a complete mall in New Jersey.Any of you in the bed bug business will know that some of this information is correct. There is a bed bug epidemic growing in the country, with stores and businesses are being affected, as well as hotels, homes and apartments. In addition, they are difficult to control. What's fishy about this email is the alarmist tone about finding bed bugs in new clothing from retail clothing stores.
“He says that since much of our clothing, sheets, towels, etc. now comes from companies outside of America, (sad but true), even the most expensive stores sell foreign clothing from China, Indonesia, etc. The bed bugs are coming in on the clothing as these countries do not consider them a problem. He recommends that if you buy any new clothing, even underwear and socks, sheets, towels, etc. that you bring them into the house and put them in your clothes dryer for at least 20 minutes. The heat will kill them and their eggs. DO NOT PURCHASE CLOTHES AND HANG THEM IN THE CLOSET FIRST. It does not matter what the price range is of the clothing, or if the outfit comes from the most expensive store known in the U.S. They still get shipments from these countries and the bugs can come in a box of scarves or anything else for that matter. That is the reason why so many stores, many of them clothing stores have had to shut down in NYC and other places. All you need is to bring one item into the house that has bugs or eggs and you will go to hell and back trying to get rid of them. He travels all over the country as an advisor to many of these stores, as prevention and after they have the problem.
“Send this information on to those on your e-mail list so that this good prevention information gets around quickly.”
I was curious whether this was an isolated email, and whether it had spread widely, so I checked with Snopes.com, the urban myth-debunking site. I did a quick search on bed bugs and the exact email appeared. Posted on Snopes less than a week ago, this one appears to be just beginning to spread through cyberspace.
Snopes rates emails as True, False, or a mixture of truth and falsehood. This one they rate as a "mixture". I agree with their analysis that the chance of getting bed bugs from packages of new clothing is extremely remote. I’ve never heard of this happening, and would be surprised to hear about a confirmed case of bed bugs traveling in this way.
This email follows the pattern of a classic hoax that seems designed to scare people into worrying about things they needn't worry about, or encouraging them to take an unnecessary action (Remember the hoax about the deadly "blush" spider that lives under toilet seats? It urged everyone to always check under public toilet seats before sitting down?) I'm not sure what prompts people to concoct these wild tales, unless it just gives someone the jollies to think about the thousands of frightened people checking their toilets. All of us are prone to fall prey to a practical joke from time to time, but as professionals we can at least be ready to correct nonsense about pest control when it occurs. So the message here I guess is: "Don’t stop shopping for new clothes; the economy is bad enough as it is."
The Snopes site, by the way, is chock-full of insect lore, strange fact, and legend. Try a search on "insect", "rat", "spider" and "ant" and see what you find.
Monday, October 4, 2010
Termidor label expanded for crazy ants
The Termidor label is expanding under the Texas' Section 18 emergency exemptions program to accommodate the expanding range of the Rasberry crazy ant in south Texas.Termidor has been a useful insecticide to help prevent crazy ant invasion of homes. Unfortunately, because of the very high numbers of these ants in infested yards, the traditional "one foot up, one foot out" broadcast treatment allowed on standard labels has been inadequate. The new label allows application "3 feet up and 10 feet out" up to twice a year. Hildalgo County has been added to the list of counties where the expanded label may be used, and a provision on the label also allows use in unlisted counties if those counties have been listed as infested by Texas A&M University entomologists.If you are not sure if your county has been included in the new label, Ed Gage of the Texas Department of Agriculture suggests that you visit their page listing the current known counties of infestation. Another site to check is the Texas A&M University crazy ant website. According to Gage, as with any Section 18 label, if the label you have in your hand does not include your county, but the county has been declared infested, simply make a copy of the new label, print it off and carry it to your application site. For a copy of the latest label, as of October 1, 2010, ask your local pesticide distributor, or click here. More up-to-date labels may be available on the TDA website.
The term Section 18 label refers to a section of the federal pesticide law referred to as FIFRA (Federal Insecticide, Fungicide and Rodenticide Act). Under Section 18, states may grant exemptions to label provisions if an emergency is determined to exist. In the case of the new crazy ant, the first exemptions were granted approximately one year ago on October 21, 2009. The exemption will be allowed until October 21, 2012.
What do socks and bulletproof vests have in common?
For years I have heard speakers talk glowingly of spider silk--about its tensile strength that is greater than steel, its amazing ability to stretch, and its ability to retain its strength at temperatures as low as -40 degrees C. It also is thought to possess antimicrobial properties that might make it useful in medicine. Possible uses of spider silk include making superior surgical suture thread, bullet-proof vests, automobile air bags and other strong, lightweight fabrics that could be used for clothing like running socks and athletic shirts.
Unfortunately, spider silk is amazingly difficult to obtain. Spiders have been milked, or more properly, "silked"; but this impractical for obtaining all but the smallest quantities of silk. This is what makes the Notre Dame story interesting. Molecular biologists have attempted in recent years to product silk through the process of genetic engineering. One apparently failed biotech venture involved insertion of spider silk genes into goats, that produced silk in their milk. The idea was that the silk could be extracted from the milk. Lately researchers have focused on inserting spider silk genes into the all-time best producers of silk, the silkworm caterpillar. The result is a caterpillar that spins a combination of silkworm and spider silk, with improved toughness and elasticity.
All this reminds me of the many times people have asked me, "What good is that bug?" Spider silk research is just one example of the many amazing products that are possible if we protect, and take the time to learn about our biological heritage. Who would have guessed that tiny spiders might hold the secret of antibacterial socks, or a better air bag in your car? And what other useful insects or arthropods are out there, if we just take the time to preserve and study them? All this becomes especially significant when you consider that hundreds of thousands of insects will likely go extinct over the next 50 years if habitat destruction is not controlled. The loss to humankind of failing to protect these resources is literally incalculable.
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