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.

Bee protests are cute, but...

A recent protest by organic activists outside a Chicago Home Depot highlighted something of the current debate over pesticides and bees.  It also reminded me that no one wants to go on record as being "against the bees".  Check out the video above.

The folks in the bee costumes in the above video are protesting the retail sale of "bee-killing" insecticides called neonicotinoids. They represent groups demanding that these insecticides not be sold, and that stores begin selling only nursery plants that have not been treated with these insecticides. I've blogged about this issue in the past, and reported on some recent urban incidents that could affect the pest control industry.

Over the past few days there has been some interesting discussion on this subject in a chat group that I belong to. I thought I would share some of the more interesting comments and new studies on the subject.

• Bee experts are mostly in agreement that Colony Collapse Disorder (CCD) in honey bees is not as simple as "bad" pesticides. In fact pesticides may have little to do with bee declines in some areas.  Australia may be instructive in this regard. Australia uses neonicotinoid insecticides like the rest of the world, but Australian honey bees are not in decline. A new Australian government report out this month confirms as much, and concludes that take as a whole, neonicotinoid use has led to an "overall reduction in the risks to the agricultural environment from the application of insecticides." 
• A recent collaborative paper in the journal mBio, by Chinese and U.S. scientists, found a virus that has been known for many years, tobacco ringspot virus (TRSV), that is infecting honey bees.  This virus is the first known plant virus that has mutated and adapted into an animal-infesting virus.  It appears to be transmitted to bees via pollen, and also by varroa mite. And its presence in bee colonies appears to be associated with gradual declines in bee colony vitality.
• In fact, varroa mites in combination with viruses are currently under close scrutiny as a major explanation for CCD.  According to Dr. Richard Cowles, with the Connecticut Agricultural Experiment Station, "When combined with work on Israeli Acute Paralysis Virus and a demonstration that irradiation of hive equipment from CCD could prevent nukes from succumbing to CCD, the strongest evidence for the cause of CCD is the varroa/viral combination."  An interesting side observation is that Australia does not yet have varroa mite, which lends strength to the argument for a mite-vectored virus explanation for the disease.
• Most studies that have found neonicotinoids in pollen have been on herbaceous plants. In one study on red maple trees, a dissertation by Dr. Josephine Johnson at the University of Maryland, no imidacloprid was found in tree nectar and only extremely low levels in pollen (bees feeding on these trees had no evidence of insecticides, nor in hive collected nectar).  So if you do neonicotinoid root applications on trees per label instructions, there is no evidence right now that such applications pose any risk to pollinators.
• Two new Washington State University Extension publications are now available on CCD and neonicotinoids.  The first publication by Lawrence and Sheppard, provides an overview of the problem with an explanation of the various factors thought to contribute to CCD.  How to Reduce Bee Poisoning from Pesticides is a thorough overview of practical ways to reduce the risk of bee poisoning due to pesticides, and includes a table of most commonly used pesticides with their potential risks to bees. 

None of this is to say that there are no legitimate concerns about the toxicity of neonicotinoids to pollinators. These products are certainly toxic to bees, and at levels lower than previously recognized. But research in this area is ongoing, and our understanding of the possible factors that might be hurting bee populations is much better than it was a few years ago. Despite what you might hear, both EPA and the pesticide industry is taking pollinator concerns seriously and is acting to make sure that you have safe tools to control pests effectively. After all, who wants to be "against the bees"?

Pennsylvania researchers summarize progress on Colony Collapse Disorder in bees

Colony Collapse Disorder, or CCD, has certainly had its fifteen minutes of fame over the past two years. A serious problem for commercial beekeepers, this new threat to managed honey bees has puzzled researchers. For an up-to-date report from the leading U.S. research team, check out the new article in Scientific American magazine. According to researchers, pesticides, often singled out as a likely culprit in bee die-offs, have not been ruled out as a factor in colony deaths, but less likely as a prime cause. New molecular techniques seem to point to a recently discovered virus as the principal suspect.

Report from Reno

Five days and 27 pages of hand-scribbled notes later and I've returned from another Entomological Society of America annual conference. As usual, the meeting was an exhausting marathon of meetings and posters and mixers, sweetened by renewed personal contacts and much new and useful information about entomology and pest control.

Some of the sessions were probably topics only an entomologist would find fascinating, like measurements of insect diversity on Arizona mountaintops, how mosquitoes locate their hosts, or the history of DDT (which cost only $.18/ lb after WWII and even the famous Winston Churchill called "the miraculous powder"!). Nevertheless, there was much information that would be of great practical interest to a gathering of PMPs. Just a few valuable new insights and reports included:

• An update was given on colony collapse disorder (CCD) of honey bees by Diana Cox Fisher, a researcher from Pennsylvania State University, who believes that a combination of stresses and new, or re-emerging, diseases (not pesticides) is probably responsible for the current crisis in bee deaths--at least in the U.S. Currently the best correlation with CCD seems to be a disease known as Israeli Acute Paralytic Virus, although the jury is still out on this one. She noted at the end of her presentation that one out of every three bites of food that we eat is thanks to pollinators like the honey bee.
  
• Several interesting papers were presented on bed bugs. Mike Potter, of the University of KY, noted in his talk on the history of bed bugs, that within 5 years of the introduction of DDT, researcher John Osmun of Purdue University reported that it became nearly impossible for researchers to locate bed bug infestations to study. Tim McCoy, of Virginia Cooperative Extension, noted the importance and effectiveness of dusts as a tool in bed bug control. Tempo dust, Drione, and Tri-die dusts gave the fastest kill of all products (45 minutes to 6 hrs). Boric acid dust was the slowest, requiring over 18 days to kill. Dini Miller of Virginia Tech concluded that hydroprene was a useful additive to conventional sprays for bed bugs (especially resistant populations), though the effects of hydroprene are subtle and may not become evident until the second or third generation.
• One of the most interesting bed bug talks was given by Changlu Wang of Purdue University. He compared spray-based and dust-based IPM programs for bed bugs. The liquid spray tested was chlorfenapyr, and the dust-based program used diatomaceous earth and an innovative bed bug interceptor device placed under bed posts to trap the varmits when they try to climb up, or down from the bed. The clever traps are being sold by Susan McKnight Inc. under the trade name Climbup™ Insect Interceptor. Both spray and dust-based programs worked well in Wang's tests. The traps caught more bed bugs than were observed by the inspectors in all apartments. Another interesting observation was that 94% of the trapped bed bugs were in the outer bowl, indicating that they were off the bed. This shows the importance of treating off-bed locations when controlling bed bugs. These devices might be especially useful for clients with low budgets and a high motivation to help with the elimination program. Of course the effectiveness of the bowls depends on eliminating contact of the bed and bedding with the floor and walls.
• Tom Greene of the IPM Institute (organization running the Green Shield™ certification program for pest control businesses) reported results of a University of Florida study that showed that properly installed doorsweeps can reduce pest complaints in schools by up to 65%. He made an observation that I believe applies not just to school IPM programs, but to all professional IPM: "The question is not 'do you do IPM?', but 'how much IPM do you do?'" Most PMPs say they do IPM, but there is generally much room for improvement of the quality and depth of IPM done by professionals.

Should PMPs kill BEEs?

It's time to put an end to oft-repeated story that bees cannot legally be killed.

Every spring I get calls from the public looking for someone who can help them get bees out of a yard or home. This is a valuable service that I wish more pest control companies would engage in. Because pest management professionals are frequently unwilling, or lack the proper equipment and knowledge, to do bee removal, the job often goes to folks in the beekeeping business who may or may not be licensed to do pest control.

I'd be a rich man if I had a nickel for pest control salesman that's told a potential customer they couldn't remove bees, because bees are protected. This story certainly sounds credible because most people see bees as beneficial. In addition, the media this past year has talked non-stop about an imminent collapse of honey bee populations due to a condition known as "colony collapse disorder" (CCD). The truth is that bees are neither tottering on the brink of destruction, nor are they protected by law.

There is currently no state or federal law stating that pest management professionals cannot kill bees that pose a threat to health or property. One possible source of this legend may be the warning statements on some pesticide labels that prohibit the use of insecticides on certain crops or flowering plants where bees might be actively foraging. These warnings are designed to protect wild or domesticated bees from colonies that do not pose an economic threat. Indeed these warnings help protect commercial beekeepers from losing bees and honey due to pesticide contamination.

Nevertheless, when bees enter a home to build their nest, it poses a stinging threat to the family, pets and neighbors, and it can eventually create additional household pest and odor problems. Old bee nests attract mice, cockroaches, dermestid beetle larvae, ants and moths to the wall of the home where the old comb lies rotting. Furthermore, all social wasps and bees defend their nests. And nowhere in Texas is immune to the threat of aggressive Africanized bees. Even the supposedly docile European honey bee also has quite a temper when conditions are right.

Using the definition of a pest as any organism where it's not wanted, honey bees can certainly be pests. And PMPs can certainly kill or remove honey bee nests anywhere they are not wanted.

But what about the demise of honey bees? If we kill them won't that hasten their almost certain extinction? No. In fact, wild honey bee populations are, by all appearances, quite virile--at least in Texas. To my knowledge, no one is currently tracking wild honey bee populations in our state, but I can detect no decline in the number of phone and email complaints about feral bee swarms and colonies in the past few years. Although Texas has been listed as a state with CCD, at last report the bee keeping industry here has not seen the precipitous declines reported from other states.

It's still unclear what is causing these declines in honey bees in the U.S. and abroad. There are numerous viable theories including new viral diseases, parasitic mites, stress from their high-maintenance lifestyles, and agricultural pesticides. But our Texas honey bees appear to be in no immediate danger.

As far as the ethical question about whether PMPs should kill bees or not, in my opinion this is more of a personal preference, with no one answer being right for everyone. As with anything, the decision involves trade offs: the benefits of reducing risks from stings and possible serious injury (even death) versus the decision to kill what is usually considered a beneficial insect. The economic cost of having to remove bee nests from walls, floors and ceilings of homes, versus the decision to destroy a swarm of bees sitting in the tree outside the window.

But why even talk about killing bees when they can (often) be removed alive? Live bee removal can be, and is, done by some companies, but not everyone has the expertise or the extra time to devote to live bee recovery and restoration. Simply, you can take them alive, but it will usually cost you more. Again, this becomes a personal decision on the part of the homeowner and the business owner.

Ultimately, the relatively few bee colonies that are exterminated from the walls and backyards of homes are not going to have much impact on the big picture of bee survival in Texas. So go out there and remove bees, and make money doing it. But if your company doesn't do bee removal just say so. Don't tell consumers that it's illegal.