Beneficial Microbes May Guard Bees' Health

By Marcia Wood
August 11, 1998

Helpful microbes that live in the hives, stored food and bodies of healthy honey bees might hold the key to protecting tomorrow's bees from chalkbrood disease.

The disease, caused by the harmful Ascosphaera apis fungus, can be costly to beekeepers, growers and consumers. That's because healthy honey bees are needed to pollinate crops ranging from apples to zucchini.

There are no chemicals registered in this country for controlling chalkbrood. But microbes such as certain bacteria, yeasts and molds apparently produce compounds that inhibit growth of the fungus, according to microbiologist Martha A. Gilliam of the Agricultural Research Service's Carl Hayden Bee Research Laboratory, Tucson, Ariz.

Gilliam has combed hives of healthy honey bees in the United States and abroad in her search for beneficial microbes that might become the basis for a commercial product for battling chalkbrood. To date, promising candidates include certain Penicillium, Aspergillus, and Bacillus organisms.

Chalkbrood attacks bees when they are still white, worm-like larvae. Bee larvae emerge from pinhead-size eggs laid by the queen bee. Later, larvae transform into cocoon-forming pupae. Young bees emerge from the pupal cocoons.

Larvae can become infected when they eat pollen contaminated by the fungus. Also, the nurse worker bees that tend the colony's young, or "brood," may inadvertently spread the fungus to the developing bees.

Larvae attacked and mummified by chalkbrood look like tiny sticks of chalk. Mummies may be white, black, or greyish and mottled. The August issue of the ARS monthly magazine, Agricultural Research, has details about the chalkbrood research. See it on the World Wide Web at:

/is/AR/archive/aug98/bees0898.htm

Scientific contact: Martha A. Gilliam, USDA-ARS Carl Hayden Bee Research Center, 2000 E. Allen Rd., Tucson, AZ 85719; phone: (520) 670-6380, ext. 121, fax (520) 670- 6493, templin@tucson.ars.ag.gov.