Suite à l'activité de ses groupes de travail en 1997, le FRAC publie son bilan et ses recommandations pour prévenir ou maîtriser les risques de résistance de champignons phytopathogènes aux fongicides.
Vis-à-vis des IBS (Inhibiteurs de la biosynthèse des stérols), les recommandations ne changent pas sur céréales, betterave, vigne, pommier, bananier et fruits après récolte (la situation vis-à-vis des résistances est stable ou varie légèrement selon les parasites).
Vis-à-vis des phénylamides (anti-mildiou) la situation est stable sur pomme de terre et vigne, la résistance est confirmée sur tabac et laitue sans gros problèmes d'efficacité ; les recommandations ne changent pas.
Vis-à-vis des anilinopyrimidines pas de problème aujourd'hui mais il faut prévenir les risques : limiter le nombre d'applications (Botrytis, Venturia ) et réfléchir leur positionnement (surtout Venturia ).
Vis-à-vis des strobilurines, sans problèmes aujourd'hui sur plantes, il faut prévenir les risques : limiter le nombre d'applications (séquences de strobilurines successives), alterner ou mélanger avec des fongicides à autre mode d'action.
Vis-à-vis des imides cycliques (dicarboximides) comme vis-à-vis des benzimidazoles, l'existence des résistances est connue depuis longtemps ; les recommandations d'usage restent valables.
Subsequent to the activities of its different working groups in 1997 the FRAC takes the opportunity to publish a review of these activities and to provide recommendations for the prevention and control of the risks of fungicide resistance in plant pathogenic fungi.
As far as SBI (sterol biosynthesis inhibitors) are concerned, the recommendations are the same for cereal, sugar beet, grapevine, apple and banana crops, as well as for post harvest fruits, since, depending on the parasite in question, the situation of resistance is either stable or improving.
Turning to anti-mildew products (phenylamids), the situation is stable for potato and grapevine crops. Although the question of resistance is confirmed on tobacco and lettuce crops, the efficacy of the products is not as yet called into question : the recommendations remain unchanged.
There is currently no problem as far as anilinopyrimidins are concerned, but future risks must not be ruled out and must therefore be prevented : the number of applications (Botrytis, Venturia) should be limited and great thought must be given to the positioning of the application, particularly for Venturia.
Although strobilurins currently give no cause for plant alarm, future risks must not be overlooked, and must therefore be prevented, by limiting the number of applications (successive sequences of strobilurins) an by alternation or mixing of different fungicides.
Finally, as far as cyclical imides are concerned, (dicarboximide) and also benzimidazol, whose resistance has been known for some time now, the established recommendations remain on the agenda.
