One of those September pursuits is the ephoron leukon hatch, or the white mayfly. It's not as common in its emergance in southeast Minnesota streams as it is on streams in Wisconsin, but if you know what you are looking for, you can find it. There are a few key things to consider if you want to fish this late season hatch. The ephoron leukon nymph is a burrowing nymph that thrives in the banks and beds of streams with silt, mud, and the likes. In years that have summer floods, unlike this one, the hatch is typically not as strong as it is otherwise. Water and air temperatures matter a great deal. When the weather cools off from the desired Indian Summer effect, the hatch gets stronger. It's also an evening hatch with a sometimes very small window of opportunity.
The few bugs that I saw bouncing around, and these adults do bounce like caddis on the riffles, didn't come off until 6:15 or so this past week. I was off the water an hour later as darkness set in, and visibility of even a larger mayfly was nearly impossible. This is when wearing a small head lamp or having one of the small lamps that slide on to the bill of your hat comes in very handy.
Patterns that I have used to successfully catch trout during this hatch are pretty simple, really. For dry fly lovers, this is a pretty large mayfly as mayflies go, and trout will not hesitate to smash these flies. I tie dries in a parachute with white poly-pro for added buoyancy on a size 12 dry fly hook. I'll mix in some #14 dries as well. If visibility is an issue,consider using some pink antron for your posts. The color of the body ranges from cream to white. One of the more successful ways to fish this dry is to add a dropper. A #12-14 Hare's Ear will work very well. Give the fly some movement. Skate it and skitter it like a caddis, and don't be afraid to give it a lift at the end of the run.
Choice of gear is essentially up to each person, but I prefer at least a 9' rod for high sticking, mending, lifting, and skittering the dry. I used a three weight rod this past week, and it was more than adequate. A four to five weight rod of similar lenghs would be a good choice also.
The ephoron leukon hatch probably gets very little notice or discussion in southeast Minnesota, but it is a fun late season hatch that typically gets the trout feeding, especially some of the larger fish.