La résistance de Botrytis cinerea aux benzimidazoles et aux imides cycliques: situation dans les vignobles alsaciens, bordelais et champenois¹

Abstract

Dans les vignobles alsaciens, bordelais et champenois des experimentations sont entreprises pour suivre l'évolution des phénomènes de résistance de Botrytis cinerea aux fongicides. Dans le cas des benzimidazoles (bénomyl, carbendazime, méthylthio‐phanate), toutes les souches présentent un haut niveau de résistance et en 1980 leur fréquence moyenne était de 63 %. Ceci implique que le réemploi des benzimidazoles est improbable dans un proche avenir. Avec les imides cycliques (iprodione, procymidone et vinchlozoline) la situation est moins critique car il n'y a pas d'inefficacité notoire, bien que des souches résistantes soient présentes dans la nature. Ceci peut s'expliquer par le fait que les niveaux de résistance sont bas; cependant des souches hautement résistantes sont décelées et dans l'avenir il faudra surveiller leur évolution.

Control of low-level dicarboximide-resistant strains ofBotrytis cinereaby dicarboximide fungicides

“…In practice, B. cinerea can establish infection both from conidia, dispersed by air currents, and from mycelium, when for example infected petals fall on to healthy leaves. Although the relative importance of conidial v mycelial infections will differ depending on circumstances, our finding at least partially explains how disease control can apparently often be achieved despite the presence of low-level resistant strains (Leroux et al 1982;Lorenz & Eichhorn 1982;Schiiepp et al 1982;Beever & Brien 1983). The conclusion that iprodione can provide at least some control of resistant strains differs from that of others who have investigated this problem (Kat an 1982;Pappas 1982;Takeuchi & Nagai 1982;Panayotakou & Malathrakis 1983).…”

“…'To whom correspondence should be addressed. Received 25 July 1983;revision 29 September 1983 without causing obvious loss of disease control (Lorenz & Eichhorn 1982;Leroux et al 1982;Schiiepp et al 1982;Beever & Brien 1983). In contrast to this situation, high-level resistant strains (EC,• values for mycelial growth >5 mg/litre) have seldom been recovered from the field (Beever & Brien 1983) although they can be readily isolated in the laboratory (Leroux et al 1977).…”

A survey of resistance to the dicarboximide fungicides inBotrytis cinerea

“…There have subsequently been reports of low-level resistant strains outdoors in England (Fletcher & Griffin 1981), in France (Leroux et al 1981a), andin Switzerland (Schiiepp et al 1981) but to our knowledge no reports of major breakdown of disease control in outdoor crops, (Maraite (pers. comm.…”

Sensitivity of populations ofBotrytis cinerea to triazoles, benomyl and vinclozolin

“…Protectants are not affected by development of resistance because of their multi-site effects, whereas benzimidazoles selected rapidly for highly resistant pathogen populations [Bollen and Scholten, 1971;Schuepp and Lauber, 1977]. Dicarboximides, which generally replaced the benzimidazoles during the late 1970s and early 1980s, also severely suffered from resistance development [Holz, 1979;Lorenz and Eichhorn, 1980;Leroux et al, 1982].…”