White Fly
The White Fly is an essential trout fly that imitates adult ephoron mayfly (white fly). It supports White Fly fly pattern, dry fly for trout, and how to fish White Fly searches.
Imitates: Adult Ephoron mayfly (White Fly)
Quick Reference
- Best Sizes
- #12-16
- Best Season
- Late summer (July-September)
- Best Conditions
- Mass evening hatches on Susquehanna, Yough, White Clay, Lower Potomac
- Water Temp
- 65-78°F
- Recommended Tippet
- 4X-5X
How to Rig It
Single dry on a 9 ft 4X leader. During peak emergence trout get so aggressive a small dropper is unnecessary.
How to Present It
Cast across and slightly down. Mend once and let the fly drift through the feeding lane — White Fly takes are violent.
Why It Works
When Ephoron emerges in summer, every fish in the river feeds at once for about an hour. The all-white silhouette is unmistakable to trout, smallmouth, and panfish alike.
History
Eastern anglers wait all year for the White Fly hatch on the Susquehanna and Lower Yough. Drift boats fill the river at sunset in late July.
Pro Tip
Be on the water at last light with a headlamp. The hatch turns on fast and ends in 60-90 minutes — miss the window and you miss the whole show.
Frequently Asked Questions
When does the White Fly hatch?+
Late July through mid-September, peaking in August. Always at last light, often after sunset.
What rivers have a White Fly hatch?+
The Susquehanna is the most famous, but the Lower Yough, White Clay, and Lower Potomac all see strong emergences.
Not sure if White Fly is right today?
Get a fly recommendation based on live water temp, flow, sky, and time of day for any river in the US.
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