The big news here is that Varroa has become resistant to fluvalinate treatments. This was reported in my letters dated February 28 and March 20 and 23, 1997. 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); more recent information indicates that this is no longer true for Switzerland. 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 importing queens.
2. The author further states that Apistan® has not gone bad as a product; it still functions well (99 percent control) in areas where resistance has not appeared. He says 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 he says. 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. It may have come by way of queens imported from Italy in the Maine-et- Loire region. In the Côte d’Or it could have resulted from migratory movement from the southeast. Principal migratory routes appear to be through the Garrone and Saone valleys. Many rural areas are not affected by migration (called transhumance here) and thus, it is thought that resistance will spread very slowly through the country. A map accompanying the article shows only 14 of 98 départments are affected so far. As I have been told in my meetings here with beekeepers, however, the south (Provence-Alpes-Cote d’Azur region) is very much affected. The article concludes that use of Klartan® (European relative of Maverik® marketed in the U.S.) in or near areas of resistance is a huge risk as some beekeepers in Italy have lost hundreds of colonies while using this material.
Treatments available in 1997 to beekeepers include Apistan® in areas where resistance has not appeared, according to the article. If resistance is suspected, CNEVA, the veterinary service, (see my letter dated February 28, 1977) and the company distributing Apistan® called Swarm, can be contacted to determine if it is present. Beekeepers who migrate long distances are also urged not to use Apistan® or other fluvalinate formulations. The issue of what beekeepers should use instead, however, is not addressed in the article. As I have related in an earlier letter to the Apis-L list (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 (see my letter dated March 23, 1997) 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. A company called Laboratoires Biové, Rue de Lorraine, 62510 Argues, tél 3 21 98 21 21, fax 3 21 88 51 95 is distributing this material.
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®. In a reprise of the CNEVA meeting in Sofia- Antipolis (see my letter to the Apis-L list 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.