This article was included the book “Modern Terrestrials” by Rick Takahasi and Jerry Hubka. It was just released this fall. It was included in the Fishing Terrestrial: Tips from the Masters section. This is the version I wrote and edited myself (with some help from Beth and Susan). If you compare it to the version in the book you will notice that the editors at Stackpole Books did some further editing.
Doug Swisher and Carl Richards introduced the idea of super hatches in in their book Selective Trout in the early 1970’s and Western Green Drakes were included on that list. Being the largest mayfly to emerge in the Roaring Fork Valley river system this mayfly belongs as part of this group. The trout on the Frying Pan and Roaring Fork really key into this mayfly. They usually begin to appear in late June or early July. The hatch then moves up river and is in the Frying Pan during early August. This year they were still present in earlier October. As an angler, once you see a few green drakes you can usually begin fishing your green drake patterns and have success. Often green drakes will hatch simultaneously with other insects, especially pale morning duns. During these complex hatches, the fish will usually respond to green drakes, although having your PMD patterns is a good precaution for those fish that are keying on that mayfly. This is the premier hatch on the Frying Pan and some of the best fishing of the season can be had when this mayfly appears.