Why Is the Dormant/Delayed-Dormant Season Important in an IPM Program?
Oil applied during the dormant period damages walnut trees. However, oils can be safely used in some varieties during the delayed-dormant season, but timing must be precise because injury can also occur between budbreak and shoot elongation. The main targets of delayed-dormant oil applications are scale (European fruit lecanium, frosted scale, walnut scale) and mites (European red mites). However, if you observe high rates of parasitization, you may delay treatments until after crawlers emerge in late spring when oil treatments are safer.
