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An in vitro evaluation of tagetes minuta essential oil for the control of the honeybee pathogens paenibacillus larvae and ascosphaera apis, and the parasitic mite varroa destructor / Martín J. Eguaras in The journal of essential oil research, Vol. 17 N° 3 (Mai-Juin 2005) 

Public ISBD [article]  in The journal of essential oil research > Vol. 17 N° 3 (Mai-Juin 2005) . - pp. 336-340 Titre : An in vitro evaluation of tagetes minuta essential oil for the control of the honeybee pathogens paenibacillus larvae and ascosphaera apis, and the parasitic mite varroa destructor Type de document : texte imprimé Auteurs : Martín J. Eguaras, Auteur ; S. Fuselli, Auteur ; L. Gende, Auteur Année de publication : 2006 Article en page(s) : pp. 336-340 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Tagetes  minuta  Asteraceae  Bioactivity  Apis  mellifera  Honeybee  pathogens  Ascosphaera  apis  Paenibacillus  larvae  Parasitic  bee  mite  Varroa  destructor  Essential  oil  composition  (Z)-β-ocimene  (Z)-ocimenone Résumé : Biological activity was evaluated of the Tagetes minuta essential oil in different in vitro laboratory experiments on the mite (Varroa destructor), honeybees (Apis mellifera), the bacterium that causes the American Foulbrood (Paenibacillus larvae), and the fungus that produces chalkbrood (Ascosphaera apis). Two methods of complete exposure were used for mite lethality test: by spraying in Burgerjon's tower with 10 mg of active ingredient in solution with distilled water and emulsion, and in unmodified Petri dishes (60 x 20 mm) with oil (different concentrations) diluted in 1 mL of ethanol. Ratio selection was obtained as: LD50 of Apis mellifera/LD50 of V. destructor. Determination of Minimal Inhibitory Concentrations (MIC): to P. larvae was tested at concentrations of 25, 50, 100, 150, 200, 250, 350, 450, 500, 600, 650, 700, 800 and 1000 ppm. An A. apis strain was grown on agar MY20 supplemented with variable concentrations (between 0–800 ppm) of T. minuta oil was evaluated. Results obtained in tests of total exposure showed that the concentration was able to kill 50% of mites in 24 h (DL50) and was estimated to be 4.37 mg/cage. The efficacy after spray treatment reached 56%. The ratio selection was 3:11. Against P. larvae, the oil showed MIC values ranging from 700–800 μL/L depending on the tested bacterial strains. Tagetes minuta oil in agar MY20 inhibited mycelial growth of A. apis above concentrations of 200 ppm (p = 0.0001). Oil concentrations of 700 and 800 ppm achieved maximum growth inhibition of A. apis (67% of growth inhibition on average). Tagetes minuta oil demonstrated in vitro antibacterial, antifungical and miticide activity, although this oil shows a moderate inhibitor effect compared with other essential oils of native plants from Argentina. However, this oil presents a ratio selection that would allow it to be used in field conditions with a good safety margin. It is possible that this oil can be used in combination with others, in integrated pest management strategies in bee colonies. ISSN : 1041-2905 En ligne : http://www.tandfonline.com/doi/abs/10.1080/10412905.2005.9698924#.Ui8at2F2_n4 [article] An in vitro evaluation of tagetes minuta essential oil for the control of the honeybee pathogens paenibacillus larvae and ascosphaera apis, and the parasitic mite varroa destructor [texte imprimé] / Martín J. Eguaras, Auteur ; S. Fuselli, Auteur ; L. Gende, Auteur . - 2006 . - pp. 336-340. Génie Chimique Langues : Anglais (eng) in The journal of essential oil research > Vol. 17 N° 3 (Mai-Juin 2005) . - pp. 336-340 Mots-clés : Tagetes  minuta  Asteraceae  Bioactivity  Apis  mellifera  Honeybee  pathogens  Ascosphaera  apis  Paenibacillus  larvae  Parasitic  bee  mite  Varroa  destructor  Essential  oil  composition  (Z)-β-ocimene  (Z)-ocimenone Résumé : Biological activity was evaluated of the Tagetes minuta essential oil in different in vitro laboratory experiments on the mite (Varroa destructor), honeybees (Apis mellifera), the bacterium that causes the American Foulbrood (Paenibacillus larvae), and the fungus that produces chalkbrood (Ascosphaera apis). Two methods of complete exposure were used for mite lethality test: by spraying in Burgerjon's tower with 10 mg of active ingredient in solution with distilled water and emulsion, and in unmodified Petri dishes (60 x 20 mm) with oil (different concentrations) diluted in 1 mL of ethanol. Ratio selection was obtained as: LD50 of Apis mellifera/LD50 of V. destructor. Determination of Minimal Inhibitory Concentrations (MIC): to P. larvae was tested at concentrations of 25, 50, 100, 150, 200, 250, 350, 450, 500, 600, 650, 700, 800 and 1000 ppm. An A. apis strain was grown on agar MY20 supplemented with variable concentrations (between 0–800 ppm) of T. minuta oil was evaluated. Results obtained in tests of total exposure showed that the concentration was able to kill 50% of mites in 24 h (DL50) and was estimated to be 4.37 mg/cage. The efficacy after spray treatment reached 56%. The ratio selection was 3:11. Against P. larvae, the oil showed MIC values ranging from 700–800 μL/L depending on the tested bacterial strains. Tagetes minuta oil in agar MY20 inhibited mycelial growth of A. apis above concentrations of 200 ppm (p = 0.0001). Oil concentrations of 700 and 800 ppm achieved maximum growth inhibition of A. apis (67% of growth inhibition on average). Tagetes minuta oil demonstrated in vitro antibacterial, antifungical and miticide activity, although this oil shows a moderate inhibitor effect compared with other essential oils of native plants from Argentina. However, this oil presents a ratio selection that would allow it to be used in field conditions with a good safety margin. It is possible that this oil can be used in combination with others, in integrated pest management strategies in bee colonies. ISSN : 1041-2905 En ligne : http://www.tandfonline.com/doi/abs/10.1080/10412905.2005.9698924#.Ui8at2F2_n4