What's going on with Hopguard?

[johng]

I did not know they were working on a longer lasting strip. I think if they could come up with one it would be a very good product. I have used the product and that is really the only complaint I have is it just does not last long enough. You get a good mite drop the first couple days then its done. If they could get it to last just half a brood cycle that would be a big improvement. Then just two treatments should knock the mites back pretty good.

One good thing about hopsgaurd is it a contact miticide so you don't have to worry about temperature. Formic has such a narrow temp range that it is hard to find a good time of year to use it here in the S.E.

[jmgi]

Just wondering if the mites could ever become immune to Hopguard, I understand that they have already become that way with some other earlier treatment products? John

[sqkcrk]

Section 18 approval has been granted for NY.

[Kieck]

Organisms face two possibilities when faced with a selective pressure: adapt ("become resistant") or go extinct. Hopguard would be a selective pressure.

In general, the stronger a selective pressure, the more rapidly adaptation spreads through the species. Or the more quickly a species goes extinct. More people using a product more often puts a greater selective pressure on the species if that product causes harm to the target species.

Extinction is the certain end to each species, just as death is the certain end to each individual.

Given what I know and expect of Varroa, I doubt Hopguard will cause the extinction of them.

[the doc]

i think the method of action is related of the permeability of the exoskeleton of the mite (carapice?) is more permeable to acidic compounds than the honeybee and lowers the pH of the mite to lethal levels. The principle is the same as why organic acids such as formic and oxalic also work. I have heard a theory that for the mite to develop resistance to acids and pH changes would substantial and essentially would no longer be a varroa mite.

[jim lyon]

i think the method of action is related of the permeability of the exoskeleton of the mite (carapice?) is more permeable to acidic compounds than the honeybee and lowers the pH of the mite to lethal levels. The principle is the same as why organic acids such as formic and oxalic also work. I have heard a theory that for the mite to develop resistance to acids and pH changes would substantial and essentially would no longer be a varroa mite.

It makes sense to me. We have never noticed resistance using any of these compounds.

[Kieck]

I have heard a theory that for the mite to develop resistance to acids and pH changes would substantial and essentially would no longer be a varroa mite. -the doc

Such a theory did not come from an evolutionary biologist, I'm confident. Evolutionary biologists are the ones who study such sorts of things.

I've heard similar beliefs expressed plenty of times before this. In my opinion, some folks like to believe such things to reassure themselves. What ends up happening remains to be seen, of course, but bear in mind that a number of organisms have adapted to survive in very acidic environments. If the mechanism of effect is what you describe, a simple mutation to reduce the permeability of the exoskeleton, or maybe just selection of the mites with the thickest cuticle on their exoskeletons, might be enough to provide "resistance" to such a treatment.

[the doc]

No I definitely agree with you and i am certainly no expert. One encouraging sign is that there is a fairly prolonged history of acid use without obvious resistance to it.

[jmgi]

Kieck, I'm not a scientist, so its hard for me to understand how selective pressure (Hopguard) on the mite will cause it to adapt by changing itself physiologically. I see it this way, in any species there are individuals that have subtle differences genetically, some of which may make it weaker against an outside pressure, and some that are stronger against it. More people suddenly using Hopguard and using it often I would think should have a devastating effect on the mite population in general from the start, as the mites are killed by it almost instantly upon contact. It does not appear when looking at the effects of other acids on the mite, that they have a resistance to them, and so I think one could safely say that Hopguard is capable of killing any varroa mite out there as long as they come into direct contact with it, the key being contact. With the current method of delivering Hopguard to the colony, there is no way to have 100% contact, one reason being the product evidently drys out quickly on the strips, and mites on the brood are unaffected. I agree that extinction is not possible here, but I do see where Hopguard can do significant damage to the mite population, especially if the product is improved to have a longer effective period in the hive. John

[Daniel Y]

actually extinction is not impossible. that has been proven. it is just not common or likely.

Part of the problems is that Hopguard or any other pesticide may be lethal quickly at the adequate dosage. This is not the cause of the problem obviously since dead mites do not reproduce. the problem is in the proper dosage. To often the dosage is improper, both form improper use or in every single case it is used the drying up as it is described above. A dosage dwindles. it is only proper when it is first applied. it then had a period it is improper. and it is here that the problem begins if the pesticide is not 100% effective. that means it is lethal to 100% of the mites 100% of the time. This can make proper application more complicated. more complicated increases the use of it improperly. Improperly does not kill mites it exposes them. exposure causes immunity. Only death prevents immunity. and yes a single organism exposed will develop immunity. it is not a genetic thing. it is a biological resistance that develops in an organism in it's life span. It will now reproduce and there is nothing that will kill it. Not even a proper dosage. That is the general picture anyway.

[jmgi]

Daniel Y, you are correct, there is a proper dosage that kills the mites but does not damage the bee, hopefully. What you say sounds like a logical progression of thinking, but as I said earlier I'm no scientist, therefore I can't dispute much of anything you said, you could be entirely correct on the matter. I hope that your last couple sentences don't become reality, or we will not have gotten anywhere. John

[chickenia]

Would there be an added benefit to rotate treatments, ex: Hopguard AND Apivar? Three treatments a year for Hopguard, instead...use Apivar for the second treatment with the added benefit that it lasts longer???? Just wondering here

[jim lyon]

I dont pretend to understand exactly how resistance works in a mite. Surely every type of treatment that we use results in some sort of resistance mechanism within a mite at some unknown rate. Whether it be behavioral, physical or something else. What hasnt entered the discussion, though, are the resistance capability and adaptability that bees are developing at the same time. It is clear to me that varroa dont have the same impact on hives that they first did over 20 years ago.

[jmgi]

Yea Jim, I just wish the bees resistance capability would hurry up a bit, I'm running out of time here. John

[Ddawg]

Does anyone have experience with hopguard on first year hives that started as packages?

Last year was my first year as a beek with a first year hive started from a package. In July I had 24hr mite drop counts in the hundreds, I treated with three successive Hopguard treatments. After each treatment there were more mites than I could count on the mite boards, the hive really took off. A week after the last treatment I got a zero mite count. The hive was thriving, then swarmed in October. (due to rookie management).
But overall I was satisfied with Hopguard and plan on treating my surviving overwintered hive (that a bought as a Nuc and never had any mite issues) soon.

[Kieck]

I'd like to touch on the adaptation or evolution of resistance again, hopefully briefly.

First, even the most effective treatments are not absolutes. They often list something like, "97 percent kill," or similarly high percentages. What that means is that some do survive it. If they survive for a reason other than random chance, "resistance" is born.

That resistance may come from many forms. An animal that detects an impending selective force, dodges it, and returns later could be said to have adapted to that particular pressure.

Now, a treatment that kills 99 percent of the pest is a stronger selective pressure than one that kills 50 percent of the pest population. A treatment that kills 50 percent and is used in 10,000 hives is a stronger selective pressure than a treatment that kills 50 percent and is used in 1000 hives. Remember that the stronger the selective pressure, the more rapidly resistance (or extinction) should be expected.

Alternating products reduces the spread of resistance because it reduces the selective pressure of a single form of treatment (unless cross resistance or similar factors come into play).

Keep in mind in all of this that we are discussing a specialized parasite that already demonstrated the genetic and behavioral plasticities to shift to another host species. That provides evidence of the mites' abilities to adapt and evolve.

[sqkcrk]

Whatever mite control material you use follow the label directions. They are there for a reason. If Hopgaurd calls for three applications, don't put on one and then something different, and then Hopgaurd again. It is a good idea to use one miticide and then the next time you treat use something else the next time you treat.

[jmgi]

Kieck, what host did the varroa mite originate on before the European honeybee? John

[sqkcrk]

Apis cerana and Apis dorsata.

[Kieck]

Apis cerana was the host. Once A. mellifera was introduced the region in Southeast Asia where the eastern honeybee lived, the mites made the jump to a new host.