I attended the 31st Congress of FNOSAD (Federation Nationale des Organisations Sanitaires Apicoles Départmentales), held this year in the Departement of Bouches du Rhone in the village of La Ciotat, March 21-23, 1997. The meeting is held every year in a different venue; this year’s theme was “En apiculture, que faire pour bien fare.” I am presently not clear about the translation, however, it has to do with keeping healthy bees as most of the meeting concerned what are called here, “sanitary issues,” surrounding apiculture. In addition to talks there were exhibitors, including Brian Sherriff from the United Kingdom.
Most impressive was the exhibit by the French equipment manufacturer, Ets Thomas Fils. It consisted of a modified trailer with a complete extracting and packing facility inside. The Thomas team parked the trailer, opened the sides, deployed an awning and removed a number of stainless steel holding tanks for display. They turned on the power and the machines permanently mounted to the trailer started pumping and running. In addition, a video monitor of the operation was also available on the side of the trailer. Thomas’ forty-eight page slick paper catalog is something to behold. Many things can be found here that are not routinely present in U.S. suppliers’ catalogs, such as several kinds of foundation mills.
Predictably most of the discussion at the meeting had to do with Varroa mites and their resistance to fluvalinate and Apistan® treatments. The latest issue of the Revue Française D’Apiculture (No. 571,. March 1997, pp 115-117) contains an article by Jérome Trouiller, University of Udine (Italy). According to Mr Trouiller, data over the last three years of research attempts to shed some light on the appearance of resistance.
1. Spontaneous appearance of resistance is a rare phenomenon the author states. The site of the resistance was first in Italy (probably Sicily). Data beginning in 1991 shows a step by step spread of resistance from southern to northern Italy. The Alps appear to be an effective natural barrier (resistance has yet to appear in Switzerland or Austria–see addendum below). It is logical that the phenomenon has appeared in Slovenia and in southern France where the Alps are not very high. The roles of beekeeper movement and climate have probably also affected the process. Spread of resistance has probably been enhanced by robbing and drifting adults and importation of queens.
2. The author further states that Apistan® has not gone bad as a product; it still functions well (99% control) in areas where resistance has not appeared. There is no such thing as partial resistance by mites and data show that in six different European countries where tests have been made Varroa continues to be controlled. In Austria, where Apistan® has been used since 1989, the treatment is still functional, as it is in most of France. Use of Apistan® contrary to the labeled procedure could accelerate the resistance. All beekeepers are urged to follow the labeled instructions. In areas where resistance has not appeared, there is no reason to use alternative treatments.
3. The resistance so far is in the south and east of France, according to the article, and. it came by way of queens imported from Italy in the Maine-et-Loire region. In the Cote d’Or it resulted from migratory movement from the southeast. Migratory sources appear to be through the Garrone and Saone valleys. Many rural areas are not affected by migration and thus, it is thought that resistance will spread very slowly through the country. A map accompanying the article shows only 14 departments affected so far. As I have been told in my meetings here with beekeepers, however, the area of Provence-Alpes-Cote d’Azur is very much affected. The article concludes that use of Klartan® (European relative of Maverik®) in or near areas of resistance is a huge risk as some beekeepers in Italy have lost hundreds of colonies in this manner.
Treatments available in 1997 to beekeepers include Apistan® in areas where resistance has not appeared, according to the article. The issue of what beekeepers should use instead, however, is not addressed. As I have related in an earlier letter (March 20, 1997), this is leading to a situation where every beekeeper is developing his own treatment regimen. Finally, the article suggests that it is possible for resistance to disappear over time if use of fluvalinate is discontinued.
One alternative material now being sold and advertised heavily at the FNOSAD meeting is Apivar®; which is a plastic strip impregnated with an active material called amitraz. Some beekeepers may remember that a similar product called Miticur® was headed for the market in the U.S., but abruptly withdrawn in 1993. There was an animated discussion with the regulatory people of the veterinary service (CNEVA) concerning materials to use. Two are registered and have labels or AMMs, Apistan® and Apivar®. There appears to be an interesting battle brewing between the distributors of these two products. In a reprise of the CNEVA meeting in Sofia-Antipolis (see my letter of February 28, 1997), beekeepers asked questions about the efficacy of a wide variety of materials including Apivar® and “extemporaneous treatments” and the possibility of getting many of the latter labelled in France. Of special concern was the fact that treatments now used in Italy are not yet legal in France. Officials stated that efficacy and residue data had to be gathered before these treatments could be used.
Both formic and oxalic acids are being used as alternative treatments according to Jean-Daniel Charriére from Liebfeld in Switzerland who gave a talk on the issue. However, although effective for hobby beekeepers, Dr. Charriére says his advice is generally not applicable for most commercial beekeepers because of the number of treatments necessary and the fact that before treatment is applied, an economic threshold of mites must be determined (one mite per day natural fall in July, five mites per day natural fall in August). His integrated control technology also includes trapping mites in drone brood in the spring, something not practical in most commercial operations.
According to Dr. Charriére, oxalic acid’s mode of action is not known. It could be by contact or systemic. Like most organic acids, control is better when there is no brood. It is present in honey naturally and is not a wax contaminate. However, it is extremely hazardous (must wear a mask) and laborious to apply. In summary, Dr. Charriére said oxalic acid might open the door to a new “organic” market, but cautioned beekeepers to carefully choose their treatments and not think of them as miracle cures. The following was received subsequent to my distributing this information:
Date: Sat, 12 Apr 1997 20:53:27 +0100
From: Hans-Ulrich THOMAS (email@example.com)
I have to correct you on this one. I live in Zurich, Switzerland and very close to us resistent mites have been found. The mites were tested in Udine and found resistant.
The culprit was a local beekeeper who owns a weekend house in the Italian speaking part of Switzerland (Tessin). He transferred some hives from there and that’s how the problem started.
However, there must also be some other sources, because resistant mites show up at other places in the area. It could be caused by imported queens from Italy or misuse of Klartan.
I own 14 hives and follow the treatment scheme explained by J.-D.Charriére. It works very well. After the honey flow is over, usually beginning of August around here, I first feed my bees 8 liters of sugar water and then apply a formic acid treatment. This will allow the buildup of a healthy winter bee population. In November when there is no brood around any more I spray the bees with oxalic acid. Time needed for this is about 10 minutes with our local type of hives. This combined treatment has an efficiency of about 98-100%. Quite remarkable!
Best regards and few varroas
Two students from the French National Institute of Agricultural Research (INRA) also gave presentations of their work at the FNOSAD meeting. They are trying to see what mechanisms can be found in Apis mellifera which make bees tolerate some level of Varroa infestation. Several have been found in Apis cerana, the original host of Varroa. They include temperature differences in drone brood that perferentially attracts Varroa, grooming behavior both from adults and infested brood, and varying reproductive success of female mites. Another major focus of this research is to find a chemical signal within the Varroa population which would tend to keep it in check. The role of aggregation and attractive pheromones (kairomones) may be key ingredients in this search.