FIELD STUDIES ON THE EFFECTIVENESS OF SOME ESSENTIAL OILS AGAINST Paenibacillus larvae subsp. larvae, THE CAUSAL AGENT OF AFB DISEASE*
Graciela N. Albo1; Elsa Cerimele2; María S. Re2; Marisa De Giusti3 and Adriana M. Alippi4
1 Curso Zootecnia AMG, 2 Curso Fitoquímica, 3 CIC and UNLP, 4 CIC and Laboratorio de Fitopatología, Facultad de Ciencias Agrarias y Forestales, calles 60 y 118, c.c. 31, Universidad Nacional de La Plata, 1900 La Plata, Argentina.
* Poster presented at the XXXVI Apimondia Congress, Vancouver, Canada, September 12-17,1999.
Laboratory and field trials were conducted to evaluate effectiveness of essential oils from lemon grass, thyme, oregano and savory in preventing and controlling infections of American Foulbrood (AFB) in Apis mellifera ligustica colonies.
LD50 values for oral acute toxicity tests on adult bees were calculated verifying that the essences were non toxic.
Two field experiments were designed, during two consecutive years, one as curative and the other as preventive. Treatments were applied as candies and time of consumption was measured.
Protection against infection by AFB was compared with results obtained using the antibiotic tylosin (control of effectiveness) and AFB-infected inoculated controls.
Disease recurrence was also evaluated up to one year after treatments.
Up to now, field results are not conclusive, since doses and methods of administration tested were not adequate to eliminate AFB infections completely.