August 22, 2019

Inspector’s Comments: Back to the Future

By now, a number of Maine’s beekeepers have had the opportunity to meet and inspect their hives with David Smith. Dave’s service is available due to a coordinated effort by Walt Whitcomb, Commissioner, Maine Department of Agriculture; Caudwell Jackson, Deputy Commissioner; David Lavway, Director, Division of Animal & Plant Health and Senator Russell Black, Wilton. Dave started on June 11th and is presently focused on checking hives with “issues” and performing colony inspections in areas of the state where brood disease is prevalent. In fall, the focus returns to commercial colonies.

I have known Dave for 29 years, and he was my first part-time summer assistant from 1984 to 1987 when the parasitic mites were introduced to North America. Our focus in the early and mid-80s was abating American foulbrood in resident hives, inspection of migratory hives used for pollination, and participation in national surveys for tracheal and Varroa mites. In fact, it was a sample that Dave collected in West Paris during the fall of 1987 that detected the first Varroa mite in Maine. US farmers and beekeepers were just getting over the “dress rehearsal” of national quarantines, depopulation of thousands of hives infested with tracheal mites, and the associated litigation when Varroa was detected. Being good soldiers and following orders, Dave and I depopulated that commercial operation with cyanide, but not until indemnification to the beekeeper was assured. In the final analysis, our action and that of other states did not eradicate or mitigate the spread of Varroa. Funding for the position was minimal and uncertain, so Dave moved on to his trade as a boat builder and to other ventures that included sideline beekeeping, maple syrup production, blueberry harvest crew chief, consultant for a major blueberry company, and father. As fate would have it, here we are back at it 25 years later.

Tracheal mites aren’t talked about much these days, and new beekeepers (especially northern) haven’t experienced the devastation the mite caused after it was initially introduced. Today, beekeepers do see the occasional hive with a high tracheal mite level perish in winter, but nothing like the 80 – 90% hive mortality northern beekeepers witnessed in the late 80s and early 90s. Fortunately, the majority of bee stocks currently in the US have a resistance/tolerance to the mite, since susceptible bee stocks were devastated. After the tracheal mite epidemic, there was a trend toward managing Carniolan bee stocks and darker-colored bees in the north. The simple reason was that they survived.

Today beekeepers are focused on Varroa and the viral complex associated with this parasite. In the early years of Varroa, hives were able to tolerate high mite loads without the activation or expression of latent viruses. It was common to have thousands of mites drop on bottom-board detectors after 1-3 days of treatment. As the mites became resistant to fluvalinate (Apistan), viruses spread throughout the North American bee population, and brood with symptoms known as Parasitic Mite Syndrome (PMS) became common. Later, symptoms of deformed wing virus (DWV) appeared in adult bees and occurred when mite loads reached the “tipping point.”

In recent years (2004+/-), viral symptoms are evident at lower mite loads. Northern beekeepers can no longer rely on a single fall treatment to keep Varroa and the viral complex in check. At times, hives are in need of a spring or mid-summer treatment during honey production, hence the registration of “soft” mite treatments such as MiteAway Quick Strips (formic acid) and HopGuard (beta acids) that can be used when bees are producing surplus honey.

Good News: HopGuard Approval in Maine

Good News: HopGuard Approval in Maine

On August 6th, the Maine Department of Agriculture was granted a Section 18 Emergency Registration for HopGuard. The material can now be shipped to Maine and used legally [per instructions shown at right]. The Section 18 Registration will expire on December 31, 2012 and will likely be repeated provided there are no adverse effects reported to EPA concerning the product.

HopGuard isn’t the “silver bullet,” but it does have a role in Varroa control. It is an effective miticide for about 3 – 4 days or for as long as the strips are wet. The material is not temperature-dependent and can be used in spring, summer and fall during a surplus honey flow. Hopefully, this product will offer northern beekeepers an excellent late fall/early spring “mite cleanup” since it is quite effective when hives have minimal or no brood. Be sure to read the entire label prior to use in order to ensure personal protection and efficacy, and please contact my office in the event of adverse effects to the bees or beekeeper.


Additional HopGuard product information, as well as a video of its application:



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