A potential role of tannins in the control of American Foulbrood

Abstract

Aim of study: to evaluate the use of tannins extracts in the control of the American Foulbroodpathology; and investigated if these extracts present levels of toxicity on Apis melliferaArea of study: Paenibacillus larvae Strains C1 and C2 were from Balcarce, province ofBuenos Aires (37°52?S-58°15?W), strain C6 from Rio Cuarto, in Cordoba province(33°08′00″S 64°21′00″O) and strain C9 from Concordia in Entre Rios province(31°23′32″S 58°01′01″O). Bees larvae used for toxicological assays were collected in SantaPaula experimental apiary, Mar del Plata (National Route 226, Km 10, Argentina)(37°55′48″S 57°40′59″O), belonging to the Centro de Investigación en Abejas Sociales (CIAS- IIPROSAM) from UNMdP.Material and methods: The Minimal Inhibitory Concentration (MIC) of 5 different tanninextracts were obtained by agar diffusion method on four P. larvae strains; using the MICvalue, the toxicity test on Apis mellifera larvae was performed afterwards.Main results: The MIC value presented a range of 6.9 to 898.6 µg/mL; and three tanninextracts do not present toxicity against bee larvae. Once the test was finished, the larvae fedwith the extracts that did not show toxicity, showed a significant increase in weight. Research highlights: The tanning extracts show a good antimicrobial activity against bee larvae.