Wisconsin trout stream mayfly hatches & caddis hatches

My Favorite Wisconsin Trout Stream Fly Hatches

Below are listed the more common Wisconsin mayfly hatches I have fished over the years on the NorthWest Wisconsin freestone trout streams (such as the Namekagon River, Bois Brule and White River). The X's represent individual weeks within a given month and the approximate emergence time for each mayfly. The hatch dates will vary from year to year depending on the weather, the type of stream and depending where the trout stream is located within Wisconsin.

Wisconsin Trout Stream Mayfly Hatches

Common Name	Scientific Name	Mar	Apr	May	Jun	Jul	Aug	Sep
Hendrickson	Ephemerella subvaria		--XX	XX--
Hendrickson / Sulphurs	Ephemerella invaria / rotunda			--XX	X---
Sulphurs (Pale Evening Dun)	Ephemerella dorothea			--XX	X---
Little Dark Hendrickson	Ephemerella needhami			---X	XX-
Sulphur	Epeorus vitreus			---X	XX-
March Brown / Gray Fox	Maccaffertium vicarium (formally Stenonema)				XXX-
Light Cahill	Stenacron interpunctatum				XXX-
Darth Vader	Serretella deficiens				XXX-
Speckled Winged Dun	Baetisca laurentina				XXX-
Brown Drake⁽¹⁾	Ephemera simulans				XXX-
Michigan Caddis⁽¹⁾	Hexagenia limbata				--XX	X---
Mahogany Dun	Isonychia bicolor				---X	XXXX	XX--
Tricos	Tricorythodes minutus					-XXX
Large Rusty Spinner⁽¹⁾	Hexagenia atrocaudata					--XX	X---
Little Yellow Quill	Leucrocuta hebe					---X	XXX-
White Fly⁽¹⁾	Ephoron leukon						XXX-
Blue Wing Olive (BWO)⁽²⁾	Baetis (?)	XXXX	XXXX					-XXX

Notes:
(1) - indicates mayfly nymphs that burrow in sand, silt and muck. The densest hatches for these insects will occur in those stretches of the stream.

(2) - there are several mayflies species that all fall under Blue Wing Olives (BWO) and hatch at different times during the season. Some I see are too sporatic to really get the trout's attention.

Wisconsin Trout Stream Caddis Hatches (Sedge)

I don't know the scientific names for most of the dominant caddisfly hatches, but do not under-estimate the importance of these little fluttering critters. On many of the Wisconsin freestone streams that I frequently fly fish for trout there are numerous caddisfly hatches that trigger heavy trout feeding. Some of my favorite caddisfly hatches are the Grannom (Brachycentrus), Green Sedge (Rhyacophilia), Dark Green Sedge (?), Little Black Sedge (Chimarra), Spotted Sedge (Hydropsyche), Ginger Sedge (?) and Great Brown Sedge (Pycnopsyche). You can find caddis on the rivers pretty much all summer long from East Coast to the West Coast. I prefer tightly wrapped wool for the larva stage, Gary LaFontaine's Emergent Sparkle Pupa or a small bead head, gold-ribbed hare's ear for the emerging caddis, and elk hair caddis, or diving bead head caddis for the adults.