A common consequence of using agricultural fungicides is the development of resistance by fungal pathogens, which undermines reliability of fungicidal effectiveness. A potentially new strategy to aid in overcoming or minimizing this problem is enhancement of pathogen sensitivity to fungicides, or “chemosensitization.” Chemosensitization can be accomplished by combining a commercial fungicide with a certain non- or marginally fungicidal substance at levels where, alone, neither compound would be effective. Chemosensitization decreases the probability of the pathogen developing resistance, reduces the toxic impact on the environment by lowering effective dosage levels of toxic fungicides, and improves efficacy of antifungal agents. The present study shows that the antifungal activity of azole and strobilurin fungicides can be significantly enhanced through their co-application with certain natural or synthetic products against several economically important plant pathogenic fungi. Quadris (azoxystrobin) combined with thymol at a non-fungitoxic concentration produced much higher growth inhibition of Bipolaris sorokiniana, Phoma glomerata, Alternaria sp. and Stagonospora nodorum than the fungicide alone. The effect of Dividend (difenoconazole) applied with thymol significantly enhanced antifungal activity against B. sorokiniana and S. nodorum. Folicur (tebuconazole) combined with 4-hydroxybenzaldehyde (4-HBA), 2,3-dihydroxybenzaldehyde or thymol significantly inhibited growth of Alternaria alternata, at a much greater level than the fungicide alone. In addition, co-application of Folicur and 4-HBA resulted in a similar enhancement of antifungal activity against Fusarium culmorum. Lastly, we discovered that metabolites in the culture liquid of Fusarium sambucinum biocontrol isolate FS-94 also had chemosensitizing activity, increasing S. nodorum sensitivity to Folicur and Dividend.
Keywords: chemosensitization, plant pathogenic fungi, agricultural fungicides
Citation: Dzhavakhiya V, Shcherbakova L, Semina Y, Zhemchuzhina N and Campbell B (2012) Chemosensitization of plant pathogenic fungi to agricultural fungicides. Front. Microbio. 3:87. doi: 10.3389/fmicb.2012.00087
Received: 19 December 2011; Accepted: 21 February 2012;
Published online: 09 March 2012.
Edited by:Jong H. Kim, United States Department of Agriculture – Agricultural Research Service, USA
Reviewed by:Michael Wink, Heidelberg University, Germany
Copyright: © 2012 Dzhavakhiya, Shcherbakova, Semina, Zhemchuzhina and Campbell. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
*Correspondence: Vitaly Dzhavakhiya, Laboratory of Molecular Biology, Russian Research Institute of Phytopathology, VNIIF, B. Vyazyomy, Moscow Region 143050, Russia. e-mail: email@example.com