Beekeepers no longer have to rely solely on chemicals to battle the pesky varroa mite, thanks to a new control developed by an Agricultural Research Service scientist. Entomologist Jeff Pettis and colleagues at the agency's Bee Research Lab in Beltsville, Md., developed the Beltsville Screen Insert to help thwart the mite.

Honey bees produce $270 million of honey, beeswax and other hive products and pollinate nearly $10 billion worth of crops annually. Varroa mites attach to bees and feed on them, reducing their population and inhibiting their productivity. The screen will be a boost to both hobby and commercial beekeepers who produce honey and rent their colonies for pollination services.

The screen separates the mites from the bees by creating a 1.5-inch gap between the bottom board and hive bottom. When bees groom each other, they sometimes knock the mites off. Smoke and chemical treatments applied by beekeepers also help remove the mites. The insert's wire mesh allows the mites to fall through the screen and onto the hive bottom, so the mites can't reattach to bees as they enter and leave the colony. After taking monthly samples of the fallen varroa, it was found that the screen reduces varroa populations by 15 percent.

Varroa mite infestations have become such a serious problem that maintaining bee colonies without chemical treatment is virtually impossible. Currently, the only pesticide approved for general use for varroa mite control is Apistan, a strip that contains the chemical tau-fluvalinate. But varroa mites have begun to show resistance to the chemical, so scientists are looking for alternatives such as the screen.

The screen reduces the reliance on synthetic chemical pesticides while still helping control the mites. Researchers are continually developing and improving the screen, but it is already being sold in the Brushy Mountain beekeeping supply catalog.