First results on the efficacy of different fungicide treatments applied to rapeseed according to sowing dates in Autumn 1998 | Premiers resultats sur l'efficacite de differents traitements fongicides sur colza compte tenu de la date de semis a l'automne 1998

brassica napus chemical control control de enfermedades cultivos de invierno culture d'hiver date de semis disease control efficiency eficacia enfermedades fungosas fecha de siembra fungal diseases herbicidas herbicide herbicides leptosphaeria maculans lutte chimique maladie fongique north rhine-westphalia oil crops peronospora parasitica plantas oleaginosas rin del norte-westfalia sowing date winter crops