Burr comb from a research hive at 溏心vlog免费B站鈥檚 East Farm Agricultural Experiment Station. When researchers inspect a hive to make sure it is healthy, they sometimes find comb that is out of place, called burr comb, which they remove.
Chemistry professor Matt Kiesewetter and entomology professor Steve Alm are putting their heads together to develop better ways to protect honeybees from varroa mites.
By Lauren Rebecca Thacker
When Matt Kiesewetter was promoted to associate professor of chemistry in 2018, he breathed a sigh of relief and thought it might be time to find himself a hobby that had nothing to do with his work. So, on a whim, he ordered bees.
鈥淲hy bees?鈥 he offers, and quickly answers, 鈥淚 have no damn clue. I can鈥檛 tell you why. But when I was growing up, I raised butterflies in the yard. Back then, in the country, you could grab milkweed from the side of the road and raise some monarchs. I guess that sparked my interest in insects. So, I got bees.鈥
Associate professor of chemistry Matt Kiesewetter (left) and professor of entomology Steve Alm.
Now, five years later, he鈥檚 got four hives in his backyard and more honey than he knows what to do with. And in that time, he realized that beekeeping didn鈥檛 give him the break from chemistry he was looking for, but instead gave him a new focus: controlling the honeybee鈥檚 enemy. Enter, the varroa mite.
Varroa mites, Kiesewetter explains, are the number one stressor of honeybee hives. If you鈥檙e a bee- and honey-lover, but not a beekeeper, you may be surprised by this. What about colony collapse disorder, the mysterious and widely reported phenomenon that causes worker bees to flee their hives, leaving their queen to die? Well, that鈥檚 certainly a problem, but it鈥檚 not as prevalent as it used to be. The Environmental Protection Agency reports that incidents of colony collapse disorder have dropped dramatically since the disorder鈥檚 height in 2008. If you鈥檙e a backyard beekeeper, varroa mites are probably your biggest headache.
Female mites enter and lay eggs in a honeybee brood cell鈥攚here the eggs, larvae, pupae, and adult bees develop. Mites develop alongside the growing bees, eventually attaching to a honeybee鈥檚 fat body, a type of insect tissue that is analogous to the liver in mammals. There are seven confirmed diseases that the mites bring to hives and at least a dozen more suspected鈥攁ll detrimental, some fatal. The mites cannot exist without the honeybees. So, the problem of varroa mites presents a conundrum: Beekeepers, amateur or professional, must combat the mites to ensure their hives鈥 survival, but mites can only be treated within the hives.
Varroa mites are the number one stressor of honeybee hives. Left to right: an adult female varroa mite; close-up view of a varroa mite on a honeybee host; a honeybee with a varroa mite attached to its body.
Kiesewetter contended with varroa mites in his own hives using the standard methods: synthetic chemicals, like pyrethroid and organophosphate miticides, and naturally occurring chemicals, like formic and oxalic acids, and even powdered sugar. They work, but there are risks: Synthetic miticides can lead to the development of miticide resistance, while some natural miticides are less effective and difficult to administer. And, Kiesewetter explains, most pesticides on the market are broad spectrum, meaning that they can kill many different organisms. Which means that they can kill bees, too.
鈥淭hese chemicals just happen to be a little less toxic to bees than mites,鈥 says Kiesewetter. 鈥淏ut there are sublethal effects, and some people suspect that these pesticides are harming the hives. We don鈥檛 know. But my question is, can we design a pesticide that is essentially nontoxic for bees while hitting the target鈥攖he mites鈥攖hat we want?鈥
As a graduate student at Stanford University, Kiesewetter was interested in polymer synthesis and renewable plastics. In particular, his research considers how materials, including plastics, can be more sustainable. He carried that interest through a postdoctoral fellowship at Massachusetts Institute of Technology and then to the 溏心vlog免费B站, where he arrived in 2013.
Kiesewetter realized his experience in organic chemistry could help him develop new miticides that can evade resistance, in addition to plastic-based delivery systems that could make natural options safer and more effective. What if, for example, he could construct a hive using plastic that degrades to produce a mite-controlling agent? But, while he was a pro at chemistry, he was an amateur when it came to honeybees.
Steve Alm is no bee amateur. The professor of plant sciences and entomology is an expert in pollinators of all kinds, from the honeybee to the estimated 250 native bee species buzzing around Rhode Island. Kiesewetter heard through the grapevine that Alm had hives at 溏心vlog免费B站鈥檚 East Farm.
The roughly 85-acre spread of East Farm is the place for 溏心vlog免费B站 students and faculty to experiment with flora and fauna. The location, about a mile southeast of the Kingston Campus, facilitates bobcat and coyote research; efforts to develop stronger breeds of rhododendrons, azaleas, and apples; and studies on Atlantic salmon. It鈥檚 also home to beehives and pollinator meadows.
Research associate Casey Johnson, M.S. 鈥22, in the pollinator meadows at 溏心vlog免费B站鈥檚 East Farm Agricultural Experiment Station.
鈥淚鈥檓 picturing it right now,鈥 Alm says, remembering his first meeting with Kiesewetter. 鈥淚 was in Woodward Hall teaching a course on bees and pollination. Matt came in, and he had this idea for controlling varroa mites. He had the chemistry, and I had the bees.鈥
Thus, a collaboration began.
Kiesewetter says, 鈥淚 found Steve by accident, and I couldn鈥檛 have found a better collaborator if I had tried. He has been so willing to do this work and is just great. And it鈥檚 been a lot of fun.鈥
Alm explains the risks inherent in the process of treating a hive with standard commercial products with formic or oxalic acids, both naturally occurring chemicals. 鈥淧roducts with formic acid say right on the package that they may kill your queen and up to 1,500 bees. So yeah, that鈥檚 very rough on a colony. And with oxalic acid, you need to wear a special respirator, so it鈥檚 noxious for beekeepers, as well. Sometimes the cure is almost as bad as the disease. We鈥檙e trying to find safer materials for the bees and the beekeepers.鈥
One particularly challenging aspect of studying varroa mites is their short lifecycle. Mite populations are at their peak in August, September, and October. Scientists want to study mites during this peak, but three months isn鈥檛 much time.
鈥淢y question is, can we design a pesticide that is essentially nontoxic for bees while hitting the target鈥 the mites鈥攖hat we want?鈥
鈥擬att Kiesewetter
Casey Johnson, M.S. 鈥22, a research associate, adds that while there are methods to rear varroa mites outside of a honeybee colony and their natural lifecycle, 鈥淚t鈥檚 very work-intensive and not foolproof. With our methods, we can get them to live for 24 hours in the lab outside of a hive, but that鈥檚 it.鈥
And then there are the additional challenges of maintaining the hives and controlling the scale of experiments, things Kiesewetter had to adjust to when turning his attention to honeybees.
鈥淵ou think about a hive being 50,000 bees and you鈥檙e like, 鈥極h gosh, this is great,鈥欌 he says. 鈥淏ut it鈥檚 only one hive. Fifty thousand bees are a data point of one. If you have five experimental hives and five control hives, you can see how things can get out of hand, real fast. Our initial tests are meant to figure out if we should scale up.鈥
Julia Vieira 鈥21, M.S. 鈥23, a student in Alm鈥檚 lab, tells us about a recent experiment designed to address these challenges, saying, 鈥淭he idea was, could we get another species that is comparable to varroa, and has a similar mortality rate, that we could use for preliminary bioassays when we don鈥檛 have access to varroa populations?鈥
It turns out, the answer was yes. In 2022, Kiesewetter, Alm, Vieira, and Johnson, along with colleagues Elizabeth Varkonyi, M.S. 鈥22; Howard Ginsberg, scientist emeritus with the U.S. Geological Survey鈥檚 Eastern Ecological Science Center; and Kassie Picard, Ph.D. 鈥23, published a paper demonstrating their findings.
The research, published in the Journal of Economic Entomology, tested four organic acids at a variety of concentrations on varroa mites and three insect species. The results showed that varroa had levels of mortality consistent with the other species, suggesting that other, more easily managed test subjects can be used when testing varroa mite treatments.
Kiesewetter is pleased with the experiment, which also tested methods of applying the various acids.
鈥淭hese organic acid treatments are very popular,鈥 he says, adding that he uses them in his own hives. The research gives insight into how they work and paves the way for more experimentation. 鈥淚n the future, we鈥檒l experiment with some synthetic pesticides that are less toxic to bees and more toxic for mites. We鈥檙e trying to scale up and see what kind of plastic-based delivery systems can have good effects.鈥
The beekeeping community must contend with varroa mites in order for hives to survive. And Johnson points out that varroa mites are a problem for honeybees now but says, 鈥淭here are documented cases of pathogen spillover from managed honeybees to native bees. Beekeepers,鈥 she explains, 鈥渉ave a responsibility to monitor and treat varroa to help mitigate the spread of diseases into our native wild bee populations.鈥
Bee Lab researchers Julia Vieira 鈥21, M.S. 鈥23; associate professor of chemistry Matt Kiesewetter; Casey Johnson, M.S. 鈥22; and professor of entomology Steve Alm at East Farm.
There are different perspectives on how best to treat the mites and ensure a healthy honeybee population. One approach is what Kiesewetter calls Darwinian beekeeping: using no controls, in order to develop a strain of bees with inherent mite resistance. But that鈥檚 a long game, and Kiesewetter isn鈥檛 sure it鈥檚 a realistic approach. Other beekeepers are interested in physical methods, like heating hives to a temperature that harms mites but not bees; and using powdered sugar to coat bees, then shaking them until the mites release their hold. But research, including a soon-to-be-published paper by Johnson, shows that powdered sugar is effective for monitoring mite populations, but not for eradicating them. And studies on heat treatments are in the early stages. So that leaves chemicals, synthetic and natural.
鈥淚t might sound like, 鈥極h, of course the chemist wants to use chemicals,鈥 but it鈥檚 not really like that,鈥 Kiesewetter says. 鈥淧esticides work. They have sustained the beekeeping world for decades. But if people stop using them or if mites develop resistance, that would be catastrophic for the beekeeping community.鈥
As a chemist and a beekeeper, Kiesewetter wants to keep his hives healthy, and yours, too. Even if beekeeping didn鈥檛 end up being the nonscientific hobby he first imagined, it has meant a lot to him over the years. It gave him a new direction and exciting collaborations across 溏心vlog免费B站. And don鈥檛 forget the honey. So much honey.
鈥淟ast year, I got about 200 pounds,鈥 he says, laughing. 鈥淚n the summer, people are probably tired of seeing me show up because I鈥檓 just carrying jars of honey around. I try to give it all away.鈥
Photos: Casey Johnson, Gilles San Martin, Nora Lewis
These Bees Are Locals

Since the emergence of colony collapse disorder in 2006, interest in backyard beekeeping has grown among people looking to support global bee health and local ecosystems. While keeping bees is a worthwhile hobby, there are other, less labor-intensive ways to support pollinators.
Honeybees are not native to North America鈥攖hey were brought over by honey-craving colonists in 1622. Before that, plants were pollinated by native species, including the much-loved bumblebee and the much-maligned wasp, a group of insects that Johnson calls 鈥渋ncredibly misunderstood鈥 and that she lauds for their pollinating and pest-control abilities.
We need all pollinators鈥攏ot just honeybees鈥攆or a healthy world. Of all the crops grown worldwide, about 75% require pollination. Without pollinators, we wouldn鈥檛 have pumpkins, raspberries, tomatoes, onions, or many, many others.
Kiesewetter and Alm recommend that Rhode Islanders looking to support native pollinators fill their gardens and flowerpots with native plants. Consider blueberries, bee balm, goldenrod, beardtongue, native milkweeds, hyssop, and asters. To convert your turf lawn into a bee lawn, incorporate clovers (especially medium red clover), selfheal, or creeping thyme.
If those aren鈥檛 your style, don鈥檛 worry. You can still nourish your local pollinators.
鈥淎 very simple equation is: more flowers equals more bees,鈥 Alm says.
For more information on ongoing research and pollinator gardens, visit the Bee Lab at .


A group of Master Gardeners based at East Farm as been assisting Dr. Alm and his graduate students for years by constructing and maintaining various research areas and specialized gear in the ongoing pollination project. The close-knit collaboration has been most gratifying and educational for all involved.
I’m hoping our meadow is a haven for local bees. We’re seeing more bumble bees and also a variety of small bees. Butterflies are slowly finding their way to the meadow too. It looks rather ragged, but it’s doing what we hoped it would do.