Fungicide resistance in Botrytis cinerea: updates on resistance mechanisms and management
Résumé
Resistance to fungicides is an evolutionary process resulting from the selection of advantageous genotypes in naturally diverse populations. Up to nine fungicide modes of action are authorized to control grey mould caused by Botrytis cinerea, according to the crop and the country. Out of them, six have encountered specific resistance, with variable frequencies in populations and possible consequences for field fungicide efficacy. Moreover, multidrug resistance (MDR) is caused by fungicide efflux and allows a weak resistance towards eight unrelated modes of action. Here, a review is given of the fungicide resistance status of B. cinerea, via the examples of French and Italian vineyards and some other crops. Recently developed resistance and recent findings concerning the associated resistance mechanisms are focused upon, and more particularly on fenhexamid, SDHI and multidrug resistance. The importance of properly quantifying resistance costs will be stressed, as well as the impact of fungicides on population structure. Finally, anti-resistance strategies will be presented and examples of managed resistance will be discussed in a more general manner, with the aim of extending this knowledge to other crops and countries undergoing similar resistance problems.