The Blue Winged Olive Barbless is a highly effective, dry fly for trout and grayling feeding on Blue Winged Olive duns. On UK rivers the natural is strongly associated with summer and often becomes important later in the day.
Fish it upstream on a leader when olive-bodied duns with blue-grey wings are present. Aim for an accurate, drag-free drift and match the hook size to the naturals. Fish it with confidence and be ready for the rod to bend.