As the managed honey bee industry continues to grapple with significant annual colony losses, the Varroa destructor mite is emerging as the leading culprit. And, it turns out, the very nature of modern beekeeping may be giving the parasite the exact conditions it needs to spread nearly beyond control. In an article published yesterday in […]
By Meredith Swett Walker Imagine a parasite about the size of a grapefruit, and it’s latched onto your back where you just can’t reach it. Now imagine that parasite is sucking your blood and that its cronies are reproducing rapidly in your home and attacking your family. This horrifying scenario is essentially what the mite […]
For Varroa mite control, I sprung for a ProVap110 this year. I put it through the paces this week and thought I’d report on it here.
View Video Here: https://youtu.be/yYl63Akou3E
Disclaimer first: Yes, Larry of OxaVap is a friend of mine. We met at a South Carolina Beekeepers Association conference several years ago and hit it off talking bees non stop for the duration of the conference. This was all before oxalic acid was approved for use in the United States. Larry told me then it would be the next big deal in Varroa mite control and apparently he was right as it was approved a couple years later. (Larry also told me where U.S. beekeepers were already ordering vaporizers from across the border in Canada.) Anyway, Larry and I always look forward to conferences and hanging out, telling bee stories when we can.
Before getting the ProVap110 I was using two Varrox, pan type ,vaporizers. Using two really sped up my mite treatments. Duh, twice as fast, right? No, don’t ask me how but everything moved faster and down time between hives was less so I really think I was doing the job in less than half the time than with one.
Recently, Larry suggested I needed to try the ProVap110 but I was resistant due to the issue of needing AC current. He said that most inexpensive car/truck inverters would do the job as it only used 250 watts and 2.2 amps. I checked and Harbor Freight had an inexpensive inverter. But I really wanted to be able to treat without having to drive my truck into sometimes muddy out yards. Larry assured me that a long extension cord run would not be a problem but I resisted and bought a small WEN 1800watt generator. I do plan on buying that inverter as well but the WEN1800w is under 50 pounds and, so far, I really like it and don’t have to worry about getting my truck stuck in a muddy out yard field while vaporizing mites.
One morning this week I oxalic acid vaporized 32 hives in about an hour and 15 minutes. As with the old Varrox, you still have the setup time of placing IPM boards under screened bottom boards to help seal the hive as well as a damp dishcloth across the entrance. I left the WEN1800w generator in the back of my truck and used a 50 ft extension cord. The extension cord had no noticeable effect on the operation as the ProVap performed exactly as the enclosed paperwork stated it would. I will use a 100 ft extension next time to see if that has any effect. The ProVap110 took about 2 to 3 minutes to reach its operating temperature of 230C. The unit adjusts to maintain that temperature throughout its use. I’ll place a link to a video in this post for those who have not seen how it operates. Basically, after it reaches its operating temperature a measured amount of OA is placed in a cup and attached to the ProVap110 while inverted. The nozzle is inserted into a 1/4″ predrilled hole in the hive body and the unit is spun around to its upright position causing the OA to drop into the 230C pan. The temperature readout dropped to approximately 208C when the OA came in contact with the heating unit and immediately began its rise back to 230C. Within about 20 seconds the temperature had returned to 230C and I removed the unit from the hive. An additional “cup” is provided so the user can prepare the dose for the next hive during the 20 second wait. And so it goes hopscotching down the row of hives.
Some things I learned are: 1) Hole placement is more critical than I first expected. I had used a homemade template based on the instruction sheet and some of the holes were drilled into handholds which caused me to have to hold the unit in place instead of leaving it to prep the next dose. The instructions say drill the hole 3 to 4 inches up from the bottom . I will drill future holes either above or below the handholds in the lower box – if you use cleats drill above or well below. 2) The tube that sends the vapor into the hive is copper and about 3/4″ in length. That makes sense since it is going into a hive body with a thickness of 3/4″. Longer and it could bottom out on a frame inside. It makes sense but I’d like the tube to be made of a harder metal than copper if possible – I am uncomfortable with the possibility of bending the copper tubing. 3) You will need an acid/vapor PPE mask as you will be in close proximity of the OA vapor. There is no getting around this. I currently use a 3M 7502 mask with organic vapor/ acid gas filters – $13.99 on Ebay, and non vented safety goggles – $7.99 Ebay. The mask worked great and I never even got a whiff while standing behind the hive administering the OA vapor. (more on this later)
Some of the nice things about the unit are: 1) Its speed. I usually just stood there behind the hive for 20 seconds and let it do its thing. 2) The plume of vapor into the hive is thick and sudden. The bees don’t have the “warning time” they did with pan type vaporizers to start fanning. Bang, it’s in there and done. Most of the hives didn’t object any more than they did with the pan vaporizer but a couple did. All hives settled down soon afterwards. 3) The almost constant 230C temperature ensures the OA is properly sublimated. I always suspected the gradual warming of the OA with the pan vaporizers may have wasted some of the OA as it was evaporated, boiled off, or was otherwise consumed instead of sublimated thus diminishing the dose. The ProVap110 ensures the OA always hits the pan at exactly 230C. 4) I often lose my biggest and strongest hives over the winter. I’ve always suspected it might be related to inadequate OA treatment reaching the upper boxes. Now I can treat the hive via a 1/4″ hole placed anywhere, in any box, instead of just underneath the hive. And don’t worry about drilling 1/4″ holes in your woodenware, the bees will propolize it soon enough or you can use a golf tee or dowel rod to plug. 5) It would be nice to have a half dozen of the “caps.” to prepare in advance. It’s not essential; that’s just my OCD speaking.
General comments: Most efficient use would necessitate a planned layout of the hives in the bee yard. If you scatter your hives around here and there you’ll waste time in transit. I have basically three different zones in my home yard. This meant driving the truck to three different positions and repositioning the drop cord each time. I think keeping your hives within a 100 foot radius and using a 100 foot drop cord might be ideal. Having plenty of IPM boards available is also a great time saver as transferring them hive to hive is a time waster. Luckily I have plenty to use in case of a severe winter but others may not. The hives with solid bottom boards were easiest to treat.
Now, here’s an interesting thing: The visible escaping particulate using the ProVap110 was noticeably less than when using pan type vaporizers. I can’t really account for why this is other than the bees don’t have the 2 – 4 minutes to start fanning before the deed is done. I actually used the ProVap110 in the first two hives and thought, “Did it work?” So I loaded the ProVap110, held it downwind, and flipped it to see if it was sublimating the OA. Yes, it was working and it’s done in about 20 seconds. If you look at the video, at the end the guy does exactly this and you can see how thick the plume is and how fast it comes out. Anyway, my point is, there appears to be less particulate escaping the hive than with pan vaporizers – and that’s a good thing!
Cleanup is a breeze. A little water to wash out the areas where the OA comes in contact was quick and easy. The unit itself cools off quickly when unplugged which is good and bad. Good for safety once you are done but moving into different bee yard zones meant having to wait the 2 – 3 minutes for the unit to return to operating temperature. I’m convinced I can shave 30 minutes off my first effort implementing some of the changes mentioned above.
I am satisfied with the unit over the pan type vaporizers for a few reasons: time efficiency, proper sublimation, flexibility in selecting placement of the area the OA is administered, and ease of use. I’d recommend it to anyone that starts to feel that pan-type vaporizing is taking too much of their bee management time that could be better spent more productively.
Aside from a single white morning this winter, we have had very little snow in Virginia. The weather is unusually warm and the bees seem to get a flying day once a week or so. I suspect the insect population will be robust this year, from small hive beetles to other assorted insects, due to our lack of cold weather. Soon the bees will start ramping up for spring, and I have been keeping an eye on the mite populations in Mars and Jupiter.
I have screened bottom boards on Mars and Jupiter and count the mites every few days to determine the average daily mite drop. It is nice to track this number through the winter and have a sense of overall hive infestation. As you can see, the mites were high in Mars and had starting creeping up in Jupiter in mid-November. I did an oxalic acid dribble (OAD) on Nov 28 to knock them back. Oxalic acid is an organic compound found in rhubarb, spinach, and a number of other plants. Varroa mites react poorly to it, while the bees have a natural tolerance. I treated every hive in the apiary, which is recommended since the bees (and mites) will drift from hive to hive.
Right now the mite counts are low, around 1 to 2 mites per day. Soon, as the hives start to raise new workers, the mites will increase. Last year the uptick started in mid-February, so we’ll see when it starts changing this year.
The Varroa Problem
Speaking of our most dreaded pest, it appears that nationwide mites are starting to show some resistance to the most common synthetic pesticide, amitraz. I wouldn’t touch the stuff, but many commercial beekeepers use it. This could create some serious trouble for these outfits as well as crops such as almonds that heavily depend on bee pollination. The situation prompted Randy Oliver at Scientific Beekeeping to create a series of articles calling for a new focus on developing mite-resistant honey bees. Visit his articles by publication date page to see the series so far: part 1 through part 4 as of this posting.
The articles provide an in-depth look at why varroa mites are a problem and what we should do about it. Varroa is a vehicle for deformed wing virus (DMV) and other viruses, and as the mite population increases it spreads DMV and other ills among the bees. Colonies will typically collapse from these viruses before the mites become a serious threat.
The most interesting section for me is part 3, where Randy discusses why varroa mites and DMV are getting progressively more virulent. Since commercial beekeepers tend to use bees bred mainly for growth and honey production, the resistance to varroa and DMV in these bees is rather low. This coupled with the fact that hives are kept close to each other encourages more dangerous forms of the virus to develop. If a hive collapses quickly, other bees will rob it out and bring the mites and viruses back to their hives.
If beekeepers insisted on more mite-resistant stock, the virus would spread less quickly. Hive collapses would be more likely to occur during winter, rather than before it. Virus and mite transmission would then more frequently occur in swarms and splits, which would favor less virulent strains of the virus.
Randy does a better job explaining the science (which I may not have completely correct), the point is that the majority of beekeepers would need to insist on mite-resistant stock. In fact, according to Randy, that is exactly what happened in South Africa. The beekeepers there did not have the resources to purchase miticides when varroa arrived. After devastating losses for a few years, the bees recovered and now beekeepers in South Africa do not generally worry about varroa mites. We are unlikely to eliminate the mites, we need to evolve into a more stable relationship between honey bees and mites.
It is a great series, and I look forward to future installments. Check it out.
The Times They are a-Changin’
This 1964 song by Bob Dylan was the title track on the album of the same name. Dylan wrote the song to capture the feeling of change in the 60’s, and numerous bands have performed the song as a cover since then. In 1984, Steve Jobs recited the second verse of the song during the Apple shareholders meeting, where he famously unveiled the Macintosh computer.
For this post, the times are changing for me in a number of ways. Aside from the seasonal change of the bees as we move from winter to spring, I just left my prior job this past week after over five years with the company. My new position starts on Monday, February 6, so cross your fingers for me.
We can also hope that the sense of change will take hold in the beekeeping world. It is difficult for any one beekeeper, especially a hobby beekeeper, to make an impact on the genetics of North American honey bees. We need the major queen breeders to start selecting for mite resistance, something they tend not to do today. So keep your eyes open and don’t speak too soon, cause the times they are a-changing.
May you prosper and find honey.