Though not as well known as the Hendrickson and Sulphur hatches of the Ephemerella
genus, Drunella cornuta
(Olive Morning Dun or Large Blue-Winged Olive) is nonetheless an important Eastern hatch.
Lloyd Gonzales, in his book Fly-Fishing Pressured Water
, notes that this attractive olive-green mayfly can provide good-to-excellent morning fishing in the faster sections of many streams. He also mentions that it can hatch in surprising numbers and usually faces less competition for the trout's attention than many of the spring or evening-emerging ephemerellids. Yet, cornuta
and its sister species have largely escaped the limelight. The renowned twilight hatches of big Ephemera
drakes and many other popular mayfly species command fly fisher's attention at this time of year. As the days lengthen, fishing all of the available mayfly hatches would require a pretty long day astream, so most anglers choose to focus on the late afternoon and evening activity.
Nature seems to have several recurrent color themes, and one of these is gray-winged/olive-bodied aquatic insects. Perhaps this explains why the name "Blue-Winged Olive" is often held up as the poster child for common name confusion. It has been freely applied to a multitude of mayflies in various families, genera, and species. Prior to having a well-established common name, this mayfly was referred to by Gonzales as the Olive Morning Dun. However, it has already been added to the long list of "BWOs" on many Eastern/Midwestern hatch charts.
Drunella cornuta Fly Fishing Tips
Many standard "BWO" mayfly dun and emerger patterns in size 12-16 can work well during the emergence, though the brighter (nearly chartreuse) body color of freshly emerged duns can be worth imitating at times. Rises in fast water can be dramatic and splashy, much like the rises to some emerging caddisflies. "Dead-drifted" nymph imitations work very well before, during, and even after the emergence. Although Drunella
nymphs are rather awkward swimmers, swimming nymphs can be very effective where faster water breaks into pools or eddies.
Posted by Reify
on Apr 21, 2014
Last reply on Apr 24, 2014 by Brookyman
4/21/14 - Fished the Brodhead today at the last park before last bridge on PA 191 - downstream of huge riffle section so is a great tretch for this species. I didn't get there until around 1:00 PM, took a nap and started fishing at 2:00 and there were still cornuta coming off sparsely but steadliy - until 3:30 PM. Sparse rises, but I was entertained. Is that normal or could it be because the water is unusually cold this year. Are the males and females of the same size or is one larger - and of slightly more pale coloration at take-off from surface? It almost looked to me to be two different flies, but I'm sure they weren't.
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