I'd like us to consider a concise, broadly applicable strategy to live
with parasitic mites of honey bees. There is a lot of information
available, and we're a lot better equipped now than a few years ago, but
still there appears to be a lack of consensus about basic things such as
treatment or damage thresholds, or spring cf. fall treatment.
Although there are glimmers of hope for a symbiotic relationship between
bees and varroa, they seem uncomfortably far in the future, considering
the likely loss of relatively good chemical controls, and the risk of
honey contamination from other, relatively bad chemical controls.
It would be good to have a model for sustainable management (one with a
low likelihood of failing within a few years). Below is an attempt that
I offer for discussion. It's based on some experimental results, some
basic principles of pest management, and some choices (for lack of
anything better). It has not been demonstrated to work. The control
products are those available for commercial operations in Canada and in
some European countries (Bayvarol can be substituted for Apistan as far
as the strategy goes, I think). I've omitted drone brood removal, heat
treatment and lactic acid as too labour intensive, dusts or fragrant
oils as unsubstantiated ? and other chemicals such as amitraz as
undesirable for various reasons, although I'd like to hear from anyone
who feels another product is justifiable for general use. An equivalent
"high labour" version of a strategy would be easier, since more options
are available.
I'd appreciate hearing from those of you with varroa experience, with
comments on how you think specific parts of the strategy compare to what
is the current practice in your area (including the probability of
development of resistant varroa). Options, new ideas, criticism welcome.
Kerry Clark, Apiculture Specialist
B.C. Ministry of Agriculture
1201 103 Ave
Dawson Creek B.C.
V1G 4J2 CANADA Tel (604) 784-2225 fax (604) 784-2299
INTERNET [log in to unmask]
FOR DISCUSSION
Strategy for sustainable, integrated management of bee mites
Assumptions: varroa and tracheal mites are established in an area.
tolerable tracheal mite infestation:
15 % of bees in an apiary sample in fall.
tolerable varroa infestation: 100/colony spring (=15/d1Api)
(15 varroa on a sticky board on day 1 of Apistan exposure)
1000/colony fall (= 150/d1Api)
varroa will increase as modeled in Fries '94.
colonies must be treated to survive.
adequate treatment: 90 % reduction,
(once per year when reinfestation is minor,
twice per year when reinfestation is major)
commercial beekeeping (cost, labour minimized)
General Advice: non-chemical strategies against tracheal mites: consider
mite resistant stock, installation of vegetable oil patties (March
through June), increased requeening and hive splitting with removal of
splits after a few days flight. Check varroa drop (5 to 10 hives/
apiary) on first day of each treatment (as below). When tolerable mite
populations are exceeded, continue treatments. Coordinate regionally:
mite checks, treatment material and timing. Monitor efficacy.
Short-treatment option (reduces treatment to fit lower varroa levels):
Based on mite fall on first day of treatment, reduce treatment A or B:
Less than 100 v mites: Apistan, leave only 2 weeks.
Formic, apply 120 ml/ 3 doses.
100 to 500 v: Apistan, leave 4 weeks.
Formic, apply 160 ml/ 4 doses.
Over 500 v mites: Apistan, leave 6 weeks.
Formic, apply 200 ml/ 5 doses.
1. Short winter region: (bees forage early March through October)
For 1 treatment/year, alternate years, one of A, one of B.
For 2 treatments/year, use one A and one B per year.
Spring A: 2 Apistan hive strips, installed Feb. 1 through March 10,
Fall A: 2 Apistan hive strips, installed Sept 1 through Oct 10
Spring B: 200 ml formic acid, dispensed continuously or in 5 doses,
over 3 weeks in March,
Fall B: 200 ml formic acid, dispensed continuously or in 5 doses,
over 3 weeks in September,
2. Long winter region: (bees forage mid April through August)
For 1 treatment/year, alternate years, one of A, one of B.
For 2 treatments/year, use one A and one B per year.
Spring A: 2 Apistan hive strips, installed April 1 through May 10,
Fall A: 2 Apistan hive strips, installed Sept 1 through Oct 10
Spring B: 200 ml formic acid, dispensed continuously or in 5 doses,
over 3 weeks in May,
Fall B: 200 ml formic acid, dispensed continuously or in 5 doses,
over 3 weeks in September.
Thanks
KC
|
