LABORATORY AND FIELD STUDIES ON THE EFFECTS OF THE ANTIBIOTIC TYLOSINON HONEY-BEE APIS-MELLIFERA L (HYMENOPTERA, APIDAE) DEVELOPMENT AND PREVENTION OF AMERICAN FOULBROOD DISEASE

Laboratory and field studies were conducted to determine the effective ness of the antibiotic tylosin in preventing and controlling infection s of American foulbrood disease (AFB) of honey bees. Studies conducted on immature worker bees maintained in the laboratory revealed that ho ney bee larvae could tolerate quite a range of doses of antibiotic in their diet, Intermediate doses of tylosin protected very young larvae from becoming infected by Bacillus larvae at a concentration of 1.5 x 10(8) spores/ml of diet. Antibiotic treatment had no measurable effect s on larval or pupal developmental rates until the dose reached a leth al level. Bees in field colonies readily consumed tylosin in powered s ugar, up to a level of 800 mg/7 g sugar. No negative colony effects we re noted at any dosage rates. Protection against infection by American foulbrood was compared to results obtained with 200 mg Terramycin, th e standard dose of the only substance currently registered for foulbro od control. Both 200 mg Terramycin and 100 mg tylosin protected the co lonies for up to 3 weeks. A 200 mg dose of tylosin protected the colon y for an additional week, Doses of 100 mg or more of tylosin were adeq uate to eliminate signs of AFB infection in overtly diseased colonies. (C) 1996 Academic Press, Inc.