Oral and contact toxicity of the extract obtained with hexane from Achyrocline satureioides on larvae and adult honey bees

Aim of study: To evaluate the antimicrobial activity hexanic extract (HE) Achyrocline satureioides on Paenibacillus larvae - a gram-positive spore-forming bacillus that affects larval stage and causes American Foulbrood (AFB) its oral contact toxicity adult honey bees.Area A. plants were collected in Santa Monica (32° 05’ 29” S, 64° 36’ 54” W, Córdoba. Argentina). The adults Apis mellifera obtained from experimental apiary University Córdoba, Spain.Material methods: P. 9 was previously isolated identified Laboratory General Microbiology (Dept. Microbiology, National Río Cuarto, HE by liquid-liquid extraction. minimum inhibitory concentration (MIC) determined microdilution method. This 2 ½ MIC used for vitro tests. Oral tested larvae, feeding them with both concentrations HE, while bees spread to determine toxicity.Main results: showed activity, 0.4 μg/mL. presented very low at MIC, survival percentages be around 95% larvae.Research highlights: results show this could development an alternative product safe effective treatment AFB.