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