Comparative study of tylosin, erythromycin and oxytetracycline to control American foulbrood of honey bees

摘要

The efficiency of tylosin and erythromycin was evaluated and compared to oxytetracycline hydrochloride and Terramycin (5.5% oxytetracycline hydrochloride) for the control of American foulbrood (Paenibacillus larvae larvae) in infected Apis melliferacolonies in Argentina. Oral acute toxicity tests were performed for adult bees by calculations of LD50 values at 24, 48 and 72 h, using dimethoate as the reference compound. All the antibiotics tested showed no toxicity for adult bees, with LD50 values>100μg per bee. The times of degradation in honey were analysed for tylosin and erythromycin through HPLC and bioassays, respectively. Erythromycin, as ethyl succinate, was not effective for the control of P. l. larvae at any of the tested doses (50-1600μg a.i./bee) and its degradation time in honey was about 35-40 days. Tylosin, tested as tartrate at 75-2400μg a.i./bee, was highly effective for P. l. larvae control, and also suppressed disease symptoms for 1 year after treatment. The degradation time of tylosin in honey was about 60 days. P. l. larvae was effectively controlled by oxytetracycline hydrochloride and Terramycin, but in all cases, colonies exhibited disease recurrence from 5 to 10 months after treatment. It is concluded that tylosin tartrate is a valuable alternative for controlling P. l. larvae in apiaries in Argentina.