I found this on the same site !!
Smoking Out Bee Mites
By Sean Adams
August 28, 1997
Calming bees with smoke is a long-established beekeeping practice. Now scientists have found that smoke from burning certain plants contains natural chemicals that control honey bee mites. It may have potential as an alternative to using chemicals to control varroa mites, the domestic honey bee’s worst threat.
Frank Eischen with USDA’s Agricultural Research Service in Weslaco, Texas, has tested smoke from 40 different plants to control varroa mites. The most promising are dried grapefruit leaves and creosote bush, a woody perennial. Creosote bush smoke drove 90 to 100 percent of the mites off bees after a one-minute cage test. Grapefruit leaf smoke drove off 90 to 95 percent of the mites in 30 seconds. The findings are preliminary: more research is needed before scientists could recommend that beekeepers use these plant smokes to control mites.
The ARS scientists, at the agency’s Honey Bee Research Laboratory in Weslaco, haven’t yet analyzed the active chemicals in the smoke. And they don’t know how the smoke controls the mites, but believe it either irritates or confuses them.
Varroa mites began infesting honey bee colonies in the United States in the 1980s. The mites attach to bees and feed on their blood. If the infestation is severe and left untreated, the mites can kill the entire colony.
The standard treatment for the mites is fluvalinate, a synthetic pyrethroid harmless to the bees. Beekeepers put fluvalinate-impregnated strips in their hives to kill mites. But they can only use the strips when bees are not collecting nectar and pollen. Otherwise, the chemical could contaminate the honey. Also, European researchers have reported that mites are developing resistance to fluvalinate.