TRACHAEL MITES and MAKING MENTHOL WORK
- Spring 1996
SCIENTIFIC AG CO.
P.O. Box 2144
Bakersfield, CA 93303
Trachael mites caused significant problems for some beekeepers during the winter of ’95-’96. Trachael problems increase when colonies go through a prolonged broodless spell, esp. during cool or cold weather. Out-of-state bees wintered in California’s central valley are the most susceptible but in some years (this year) problems occur in southern California. Feeding pollen patties without controlling trachael can be a waste of time and money, as some beekeepers found out this year.
Trachael infested colonies can (and usually do) go into winter with excellent (high) populations. There are plenty of bees in the hive in November, but dwindling occurs in December and January and by the time almonds start blooming many colonies are no-go’s. After the bees are well brooded up in the spring, the colony can out-run the trachael. The almond grower may be hurt more than the beekeeper by trachael unless the beekeeper is docked for sub-standard colonies (as some beekeepers were).
When colonies are making abundant honey in the summer, the effects of trachael are minimal and beekeepers can be lulled into thinking they have no problems. The trachael are there, but since new bees are coming on all the time, they aren’t considered. Once brood rearing stops in the fall, trachael populations can cause considerable damage. Keeping trachael populations suppressed in the spring is the key to controlling this pest.
“With healthy colonies, get grease patties on ASAP, or sooner. That’s solid vegetable shortening and sugar – at a 2:1 ratio. Once on, leave it there until the honey flow starts. Actually since it’s only grease and sugar leave it on all season. You won’t hurt your honey, and you’ll offer good protection all season long.” (Bee Culture, Feb. 1996, p. 72; see also, March issue pp 177-178) . Good advice.
There is some evidence that trachael mites spread other “mystery” viral and/or bacterial diseases – the mites inoculate bees with these diseases. All the more reason to control trachael. TM added to patties appears to reduce the harmful effects of trachael by keeping bacterial (but not viral) diseases in check. Keep TM in the patties as long as possible but TM is not recommended during a honey flow.
The exact mechanism for the effectiveness of grease patties against trachael (and the increased effectiveness of TM-grease patties) is not completely known. What is known is that it works and that beekeepers with the fewest trachael problems are those that use grease patties and that keep the patties in their hives as long as possible.
TAKTIK (aka Amitraz)
Evidence is coming in that Taktik (or Amitraz) is of little or no help in controlling trachael. If you’re using this material you may be kidding yourself.
Most beekeepers are leery of relying solely on menthol for trachael control because they have either experienced first-hand or heard reports that it gives erratic control. That menthol is only effective within a limited temperature range is a major reason for failures with this useful material.
Also, most beekeepers (like most people) like something that is quick and easy – pop open a hive, throw something in and go on to the next hive. This approach doesn’t work with menthol.
A number of beekeepers are getting excellent trachael control with menthol. It takes time, patience and planning to make menthol work but such efforts can be quite rewarding. Best of all, menthol is legal.
The following section gives tips on making menthol work.
MAKING MENTHOL WORK (Spring 1996)
Much of the original work on menthol was done by the USDA’s Dr. Bill Wilson who experienced erratic control in certain situations. Canadian workers expanded on Dr. Wilson’s work and the material herein was obtained from Steve Taylor, Taylor Honey Co., Montana (406)566-2673 and from the Canadian workers that Taylor talked with: Don Peer (306)862-5293, John Gruzka (306)953-2790 and Bill Hamilton (306)862-4194. As will be seen, having an accurate weather forecast can be important in making menthol work and the climate in Montana and Canada may be more conducive to menthol effectiveness although there are certainly ample times (or areas) in California where the right conditions exist.
Feb. 2001: Jan Dormaier, Hartline, WA does trachael analysis for $25/100 bees. Call her at (509)639-2577
MATERIALS (to treat around 800 hives)
12″ X 18″ corrugated cardboard “squares”.
(cut from 1′ wide roll).
25# Crisco (or solid vegetable shortening); can get in barrel from Costco or fast-food place.
Heat Crisco until it liquifies, then dump menthol in and mix (don’t do in a populated area)
Let cool to just before gelling and throw in cardboard squares.
When squares are thoroughly soaked, remove them, let them drip-dry, then place them in a (old) freezer until ready to use.
Note: Jim Rodenberg (406)653-2565 has successfully shrink-wrapped the boards without freezing them.
When ready to treat, put the freezer on back of the truck and take to field.
TIME OF YEAR
The spring treatement is all-important. According to Eric Mussen, “Spring alone is very good, but fall only is a waste of time and money.”* ”Spring” can vary from January in southern California to June in Montana.
Spring treatments are more effective for 2 reasons: you’re suppressing trachael during the summer and you’re treating a smaller number of bees than you would in the (early) fall.
Temperature is very important. Temperature should be 65 – 75ºF (70º is ideal). Too cool and the menthol doesn’t fume; too warm and bees are driven off the brood.
The boards are most effective when they are first put in the hives and lose much of their effectiveness within a few days (bees should eventually chew up and remove the cardboard). Treating late in the afternoon, when all or most of the bees are home, is best since you will be giving a lot of bees a good dose.
PLACEMENT OF CARDBOARD
Place the cardboard squares on the bottom board, corrugations up. If you place under the lid, you risk driving the bees out, esp. on a warm, sunny day; if weather is cool or cloudy under-lid placement may be O.K. Some northern beekeepers close any top entrances when treating in the spring.
TREAT ALL HIVES?
In Canada, beekeepers send a 300+ bee sample (taken under the lid) from a 40 hive apiary in for a trachael count in the spring (May, in Canada). Most beekeepers treat only apiaries that have a trachael count of over 3% (out of 100 bees from the original 300-bee sample).
It would be nice to establish a precise treatment level for trachael. Treatment levels for most California crops have been established over the past 20 years mainly through U.C. research and establishment of such levels has greatly reduced bee losses to pesticides. Not incidentally, the funding for this treatment-level research has come from grower assessments.
* from 2 page trachaei write-up in Jan./Feb. 1996 newsletter from the U.C. Apiaries; if you’re not getting this newsletter write to Dr. Mussen, Entomology Dept., U.C. Davis, CA 95616 for current subscription rate. 1 kernal of information gleaned from this publication (or any of the other bee publications) can pay their subscription costs many times over.