CAPPings – June 2020

June 12, 2020


Wow! As if 2020 couldn’t get any weirder and more worrisome, along comes May. An invasion of “murder” hornets, two named tropical storms and a worldwide protest later, and most of us are probably fearing what the rest of this year could possibly have in store.

Clemson University and the Extension Service have been busy developing plans for safely resuming normal campus and office operations.  Although the county offices and research centers remain closed to the public, agents and specialists are hard at work developing programs, conducting research and assisting clients remotely.  We have had to be innovative, switching mostly to online webinars and meetings and practicing social distancing while assisting constituents. As with most of you, we are looking forward to the time when we can again meet and offer trainings in person, and a plan to resume operations is in place. Extension will follow a three-phase plan to reopen to the public.  As of June first, most offices and research centers will enter phase one, which involves the return of essential personnel to offices while placing limitations on the number of staff present and accommodating high-risk employees.  Phase two, which might occur as early as June 15th for some offices, involves the return of most extension personnel to office operations while still accommodating high-risk employees. The offices will remain closed to the public, but there may be some limited services resumed.  The final phase will be the return to full office operations and opening to the public. Determining when offices move to the next phase is at the discretion of administration.  They will use the number of new COVID-19 cases reported in the county and the decisions of county officials to determine if that office can open safely.  This may mean that some county offices open as early as July while others remain closed.  We hope that the entire Extension Service will be fully opened by the end of the summer, but an absolute opening date has not been established to allow for flexibility and safety.

The Apiculture and Pollinator program has been operating basically in phase one since the initial shut-down, working remotely and maintaining demonstration apiary operations.  I have been involved in several web-based programs (an environmental horticulture training and several web meetings for local beekeeper associations), but mostly I have taken this opportunity to review and update old publications and to write new ones for the website. The arrival of “murder hornets” to North America created a viral sensation that consumed the Program for a couple of weeks with a flood of calls, emails, and specimen identifications from concerned citizens.  The initial hype has subsided, but it brought a larger issue to our attention which I will address in this month’s “Conservation Spotlight.”

We have regrettably had to cancel many of our program plans due to COVID.  We miss not having the Charleston Honey and Bee Expo, hosting the Journeyman course in Conway or having the in-service training we had planned for a group of excited extension agents. We are disappointed that we will not have the SC Beekeepers Association summer conference or be able to offer the field trainings we were planning for this year’s Pollinator Week (June 22-28), but we are making plans to offer other opportunities and reschedule events for the fall.  I hope that you will stay tuned into the Facebook page (@ClemsonApiculture) for announcements.

Many local associations have had to cancel their monthly meetings because of COVID restrictions.  The Clemson Apiculture and Pollinator Program would be happy to help host virtual meetings for your association if you would like to continue meeting.  Please contact me if you would like to give it a try.

Kindest regards,
Ben Powell
Clemson Apiculture and Pollinator Program Specialist

May historically is South Carolina’s driest month of the year, and it was shaping up to provide a stellar nectar flow this year.  April seemed to progress slowly because of persistent rains and low soil temperatures, but the moderately cool temperatures and steady flow of moisture in early May was making for excellent growth conditions across much of the state.  Then tropical storm Arthur hit followed abruptly by Bertha, two named storms in the course of ten days confounded by an entire week of overcast and humid conditions between them. As Bertha moved through South Carolina most of the state received large volumes of rain on soils that were already saturated.  Farms reported crop losses, many rivers peaked into flood stage where they remain and many areas experienced an abrupt end to the nectar flow.  Some colonies (including my apiaries in Horry county) began consuming the honey they had stored in April, making for a modest honey crop at best. The effects seem to be most pronounced in the coastal plain, but beekeepers statewide have made similar observations.  This year is expected to be an active hurricane season with as many as 22 named storms predicted.  Perhaps this will provide moisture through the summer and minimize the dearth, but that remains to be seen.

Now is the time to remove filled honey supers, if you have not already. If your location is experiencing a severe and prolonged dearth from the excessive precipitation in May, then your bees may be consuming what they had stored, especially if we maintain these overcast and rainy conditions.

Now also is the time to get your hive pest control strategies ready to go.  Wax moths and small hive beetles are already active and will become more prevalent over the coming months.  While strong hives with 4-6 frames of brood per hive body have no trouble keeping moth and beetle larvae at bay, colonies that are declining will likely begin to develop infestations as the adult moths and beetles begin laying eggs. It is likely that wax moths have already laid eggs in honey supers even in strong hives, and the caterpillars will be free to ravage the drawn comb after extraction if you do not take precautions to protect the drawn supers.  Some methods for controlling wax moths in stored supers are 1) freezing frames, 2) placing supers in sunny, well ventilated locations or 3) using Paramoth or other approved fumigants on stacked supers.  Old comb is much more attractive to wax moths than new comb, so it is wise to replace wax foundation after three years of use.  This also helps control pesticide exposure and brood diseases resulting from old comb.

Small hive beetles are more interested in the stored bee bread and bee larvae, so they are less of a concern in extracted honey supers.  They are definitely active now.  Look for multiple small hive beetles along top bars and inner covers when you start your inspections.  You need to consider installing traps for them.  There is a wide array of trapping options, too many for me to detail here.  Perhaps we will delve into that in the next newsletter. For more information on small hive beetle biology and trapping, visit

Varroa mite on uncapped bee larva

More importantly, it is absolutely critical that SC beekeepers begin monitoring for varroa mites as soon as the honey supers come off.  There are very few treatments that can be applied to hives when honey supers are present, but as soon as the supers are removed, the options for treatments expand.  Also, this is the time of year when mite numbers begin to rise exponentially. Although there is still some debate about what the acceptable treatment threshold should be, most specialists are settling on the 3 mites per 100 bees ratio. Others advocate that mid-summer mite tests do not account for the mites on the brood and that thresholds should be lower.  There also is not a consensus on how many times to treat or what compounds to use.  Recent research has shown that the viruses that the mites are transmitting are actually the colony killers, so your treatment threshold may be based more upon evidence of twisted wing virus or chronic bee paralysis virus than by mite counts, although there is a strong correlation between high mite numbers and these detrimental viruses.  That being said, the Honey Bee Health Coalition has developed a decision tool to help beekeepers to answer if, how, when and what to consider for varroa mite control. Beekeepers are strongly urged to visit the site and review the Varroa guide, the management decision tool, and the presentation made available for bee clubs.  In fact, if your club is not meeting because of COVID restrictions, playing the video over a zoom meeting would be an excellent way to engage your members while you are social distancing.  If you need assistance, I would be happy to help.

Worker bee with symptoms of Twisted Wing Virus

For the treatment-free contingent of SC beekeepers, it is still critical to monitor for mites.  Even if you have varroa sensitive hygiene genetics in your colonies, it does not mean that they are mite free.  It also does not mean that the viruses associated with Parasitic Mite Syndrome are not present.  If you insist on treatment-free colonies, then this is a critical time to conduct a brood break.  Naturally, colonies would have just swarmed, both the parent colony and the daughter colony will experience about a month of brood break. You can mimic this condition by caging, separating or removing/replacing queens. Also, treatment-free beekeepers quite possibly will experience higher virus loads, more declining colonies, and higher colony losses than beekeepers that treat for mites. Honey bee genetics have come a long way in recent years, and promising strides are being made with regard to Varroa resistance. Perhaps western honeybees will develop equilibrium with varroa mites eventually, but they are not there quite yet, and honeybees have not developed much immunity to the viruses yet.

Last, most successful beekeepers learn that young, vigorous queens raise vibrant, active colonies which are able to fend off diseases, pests, and environmental stresses better than older queens with idling colonies.  Beekeepers should learn to rear their own queens in order to replace their aging stocks.  Small hobby beekeepers may find that purchasing new queens each year is sufficient yet expensive, but most sideliners and commercial beekeepers quickly learn that they need a supply of replacement queens.  Anytime in the spring up to now is the time of year to begin preparing for queen production.  There are a wide array of methods, some are best for hobbyists needing only a few queens while the Jenter and Doolittle methods allow the beekeeper to produce large numbers of queens.  The Ohio State Beekeepers provide a good overview of queen rearing methods in their Queen manual, but no method of learning how to rear queens beats trying it under the supervision of an experienced queen rearer.



I awoke that Sunday morning to a headline from the New York Times: “Murder Hornets in the US!”  I immediately thought to myself, “Crap! Well, there go my plans for this week,” and I wasn’t wrong. Sure enough, a viral flurry of social media and local news picked-up the story.  Next thing we knew, everyone was seeing ‘murder hornets’ everywhere, even here in South Carolina.

The NYT story was actually old news.  Asian giant hornets were found in North America for the first time in the fall of 2019, but the NYT slapped the name “murder” on it, and it went viral.  Personally, I had never heard anyone refer to asian giant hornets (sometimes called Japanese hornets) as ‘murder’ hornets, so I went looking for the origin of the term. It appears to relate to an obscure comment a scientist made to describe the carnage asian giant hornets inflict on colonies of western honey bees.  While the term ‘murder hornet’ congers all sorts of menacing thoughts, especially for anyone already suffering from entomophobia, rest assured it is not an accepted name because it is obviously misleading in many ways. But, hey, that is just something we entomologists have to navigate.  There are many misleading common names for insects, like “barklice,” which are not lice at all, or sandfleas, which aren’t even insects, or how some people call cicadas locusts while others use ‘locust’ to refer to grasshoppers.  Personally, I’ll stick to the scientific names.

Asian giant hornets (Vespa mandarinia) are the largest hornets in the world, and they have a reputation for being voracious predators which can inflict a very painful sting.  They hail from eastern Asia, mainly the Korean peninsula and Japan, where they are significant pests of western honeybee colonies. Japanese beekeepers have long reported asian giant hornet attacks on managed colonies. These attacks often result in the total destruction of the colony, and asian giant hornets are considered to be one of the most significant pests of apiculture in the region. For this reason, it was alarming to learn last year that they were found in North America for the first time.

Asian giant hornets were found near Vancouver, Canada in late summer of 2019, and reports of attacks on honeybee colonies as well as a few dead hornets were recorded in the fall of 2019 and spring of 2020 in northwestern Washington state.  One active colony was found and destroyed in Nanaimo, Canada, but an asian giant hornet colony has yet to be confirmed in the US.  The Washington State Department of Agriculture has put beekeepers and the public on alert and is monitoring for this exotic hornet.  Because hornets build colonies from a single queen each year, it is likely to be later this summer or early fall before they can determine if the hornet is established in the region.

South Carolina beekeepers should not be concerned yet about the asian giant hornet.  It is on the other side of the continent and is not likely to migrate to the southeastern US any time soon. Its introduction does bring a bigger challenge to light. It demonstrates how easily new pests can arrive from overseas.  Actually, eastern beekeepers should be more concerned for the potential introduction of the yellow-legged hornet (Vespa velutina).  This hornet was introduced into Europe in 2004 and quickly spread to neighboring countries, where it is ravaging bee yards just like the asian giant hornet does in Japan.  Considering the amount of commerce among the eastern US, Europe and southeast Asia where the yellow-legged hornet originated, then it seems more likely that it could arrive in the southeast before the asian giant hornet.  Another hornet, the European hornet (Vespa crabro) has been in the eastern US since the mid-1800s as a result of commerce with Europe, and the yellow-legged hornet has shown itself to be proficient at thriving in the same climate as the European hornet. Consequently, almost all of the “murder hornets” seen by concerned SC residents since the NYT story ran have been European hornets which are very common all across the state.  Thankfully, the European hornet does little more than pick-off a few honeybee workers and does not attack honeybee larvae like its Asian cousins.

IMAGES CREDIT: Allan Smith-Pardo, Invasive Hornets, USDA APHIS PPQ,  Edited by Ben Powell, Clemson University.

I developed a bulletin that discusses biologies and ways to differentiate the european hornet from the asian giant hornet and the yellow-legged hornet.  It is currently undergoing peer review.  Beekeepers likely will be the first ones to notice if the asian giant hornet or the yellow-legged hornet arrive in the eastern US, and hopefully this document will help them differentiate the three.  Thankfully, for now, the only true hornet you will find in the southeast is the European hornet which is not a major threat to honeybee colonies.

If you need help with identifying hornets or any other hive pests, you are welcome to send pictures to my email at BPOWEL2@CLEMSON.EDU.


What can I plant to help the bees?  This might be the single most common question I receive, both from beekeepers and from the public.  Unfortunately, there is no simple answer to this question, because it involves time of year, soils, climate, space requirements, care, available equipment and so forth. There is one group of plants that I often mention in response… the Hollies (Ilex spp.).  Although hollies are rarely thought of as focal plants by landscapers and horticulturists, they are definitely focal plants for honey bees and pollinators.

Bees on holly blossoms

Holly flowers are mostly small and inconspicuous, so hollies are planted mainly as foundation plants (hedges or anchor trees).  When they are blooming, the flowers are prolific, and hollies make up for their lack of showiness with an abundance of nectar.  Holly flowers are small and perfectly sized for a large number of our native pollinators.  The small open flowers are accessible to honeybees, solitary bees, wasps, butterflies, flies, beetles, and just about every type of insect pollinator you can imagine.  When hollies are blooming, they will be covered in an array of pollinators. Because different hollies bloom at different times, providing multiple types of hollies extends the nectar flow in your yard.

Newly planted east palate hollies in bloom

Hollies are versatile.  The genus Ilex includes many different species that are well suited for most locations in South Carolina.  There are large trees like the American Holly (Ilex opaca), mid-sized trees like the Dahoon Holly (I. cassine), large shrubs like the native yaupon holly (I. vomitoria), and smaller shrubs like the inkberry (I. glabra) or the dwarf yaupon (I. vomitoria ‘nana’).  There are even a few deciduous species like the winterberry (I. verticilata), and these are just the native hollies that are common to the nursery trade.  When you add in the hybrids and exotic varietals like the Foster Holly (I. x attenuata), the burford hollies (I. x cornuta), box hollies (I. crenata), and my favorite, the East Palatka Holly (I. x opaca) which is a cross between our native American and dahoon hollies, then the options are bountiful.  It also should be noted that in every ecosystem in South Carolina there are dozens of native hollies that are not common to the ornamental trade, such as the swamp holly (I. amelanchier), a common midstory shrub in wetlands across South Carolina.

One particular holly common to the lowcountry is known for the honey it produces.  Inkberry hollies (I. glabra), also known as gallberries, produce a light flavorful honey that rivals that of tupelo and sourwoods in the southeast.  Inkberries grow naturally in the sandy soils of the coastal plain and are mainly understory shrubs in pine flatwoods.  There are locations in South Carolina such as the Francis Marion National Forest where longleaf pine savannahs are maintained using prescribed fire.  These areas often produce large expanses of inkberry hollies. Because inkberries bloom towards the end of the nectar flow (May-June), savvy beekeepers can collect monofloral honey from this productive plant.  Wild inkberries have a loose branching structure and fewer leaves than other hollies, so they have not been used much in landscaping.  That has changed with new varieties that are available.  Varieties such as ‘gembox,’ ‘strongbox,’ ‘densa,’ ‘shamrock’ and others make excellent alternatives to boxwoods and dwarf hawthorns, which are now suffering from unmanageable blight diseases.

Hollies perform many duties.  Besides being excellent nectar plants, hollies are excellent foundation plants for home landscapes, hedgerows for field margins, and understory forest cover. They provide preferred nesting sites for many native birds, and some hollies are essential food sources for wildlife like berry-eating cedar waxwings.

Hollies require low maintenance and care.  Once established most native hollies do not require irrigation or fertilizing, and they have relatively few pests or diseases.  This means they rarely need treatments (Yay!).  If they outgrow their space, most ornamental hollies can be sheared and trimmed without harming them.  Hollies are best planted in the fall or early winter, and most prefer well drained soil rich in organic matter.  It helps to incorporate peat moss at planting. If you are interested in planting hollies, you can get more information on our fact sheet or by contacting the Extension horticulture agent in your county.



Once rare, emerging infectious diseases such as Chronic Bee Paralysis Virus are now widespread, and the symptomology are more common.  A study in England shows that the number, distribution, and intensity of cases of CBPV have risen sharply and that there is a strong correlation between new cases and imports of new bees into bee yards.
Budge, G.E., Simcock, N.K., Holder, P.J. et al. Chronic bee paralysis as a serious emerging threat to honey bees. Nat Commun 11, 2164 (2020).


Just because carpenter bees are solitary does not mean they are not social.  This project determined what influences social interactions among carpenter bees such as when and where they use and abandon nest sites. Ostwald, M.M., Lyman, B.R., Shaffer, Z. et al. Temporal and spatial dynamics of carpenter bee sociality revealed by CT imaging. Insect. Soc. 67, 203–212 (2020).


Nicotine, a phytochemical known to reduce gut parasites in bumble bees was tested for its effect on Nosema in honeybees, to no avail.
Hendriksma, H.P., Bain, J.A., Nguyen, N. et al. Nicotine does not reduce Nosema ceranae infection in honey bees. Insect. Soc. 67, 249–259 (2020).


Ever wonder how the floral sources of honey are identified?  There is more than one method, and new DNA techniques may provide significant advances in technology.
Ralitsa Balkanska, Katerina Stefanova & Radostina Stoikova – Grigorova (2020) Main honey botanical components and techniques for identification: a review, Journal of Apicultural Research, DOI: 10.1080/00218839.2020.1765481

Honey bees on a Clemson hive



Most of the events scheduled for June and July have been cancelled or postponed due to COVID-19.

  • SCBA Summer Meeting (July 23/24) – cancelled
  • EAS Annual meeting in Orono, Maine (AUG 3-7) – cancelled
  • SCBA Journeyman Course has been postponed to the fall – TBA
  • Pollinator Week June 22-28

4H Virtual Pollinator Camp (kits still available for Abbeville, Aiken, Anderson, Edgefield, Greenville, Greenwood, and McCormick counties).  There are only a few kits left, so please contact your 4H agent if you live in the lakelands counties and are interested in getting a kit.

If your local association needs assistance holding a virtual meeting while many locations are closed to public gatherings, please contact me.

Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, gender identity, marital or family status and is an equal opportunity employer.

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