Caddis Hatches on Michigan Trout Rivers
Mother's Day caddis, summer evening emergences, October caddis, and the patterns that fish through the season.
Caddis are the most consistently present trout food on Michigan rivers from May through October. Chris Izworski covers the major caddis emergences, the patterns that work, and how to fish them on the AuSable, Pere Marquette, and Boardman.
The overlooked workhorse
Michigan trout anglers focus heavily on mayflies and tend to undervalue caddis. The mistake is real: caddis populations on most Michigan rivers significantly outnumber mayfly populations, and trout eat them in every life stage (larva, pupa, adult, egg-laying female). The Mother's Day caddis hatch in early May is a defined event, but caddis emerge continuously through the summer in smaller daily flushes that often produce the only surface activity of an otherwise quiet evening.
Caddis species in Michigan include the grannom (Brachycentrus americanus, Mother's Day caddis), the spotted sedge (Hydropsyche), the green sedge (Rhyacophila), and the October caddis (Dicosmoecus, present on some rivers). Hook sizes range from 14 (Mother's Day grannom) to 18 (small summer caddis). Body colors range from olive to tan to dark gray depending on species.
The May caddis event
The Mother's Day caddis hatch (Brachycentrus americanus, grannom) is one of the few caddis emergences in Michigan that produces a defined event with crowds of anglers on the water. It typically peaks in the second week of May on the AuSable, the Pere Marquette, and the Boardman. The hatch is dense enough that on a peak afternoon, the air over the river is visibly full of fluttering size 14 grannom adults.
Trout key heavily on the emerging pupa just before the adults reach the surface. A LaFontaine Sparkle Pupa in size 14 fished on a swing or as the dropper in a dry-dropper rig outproduces dedicated adult patterns during the peak emergence. Once the adults are on the water in numbers, switch to an Elk Hair Caddis or X-Caddis in size 14 with olive or tan body.
June through August evening hatches
Through June, July, and August, caddis emerge daily in the late afternoon and evening on most Michigan rivers. The species shift through the summer (Brachycentrus gives way to Hydropsyche, then to smaller summer species), but the fishing pattern stays consistent: trout rise to caddis from about 7:00 PM to dusk in moderate to fast water. The bigger mayflies of May give way to caddis as the dominant surface food.
An Elk Hair Caddis in sizes 14 to 18 covers most summer caddis situations, with the size depending on what is in the air. Carry tan, olive, and dark gray body colors. The X-Caddis is a low-riding alternative for selective fish. For egg-laying female caddis, an Iris Caddis or diving caddis pattern fished just below the surface works after dark when the spent adults return to lay eggs.
Pupa and larva imitations
Caddis pupae rising through the water column during emergence are heavily eaten and underfished. A Soft Hackle Caddis Pupa in tan or olive, sizes 14 to 16, fished on a downstream swing through the heart of an emergence is one of the most effective trout-catching tactics on Michigan rivers. A LaFontaine Sparkle Pupa in size 14 covers the same situation with a slightly more imitative profile.
Caddis larvae (cased and uncased) are present subsurface year-round. A Green Rock Worm pattern (Rhyacophila imitation) in size 14, fished dead-drift on an indicator or tight-line rig, produces fish during periods when nothing is hatching. On rivers like the Pere Marquette and the Boardman with dense caddis populations, an uncased larva pattern is one of the most underrated subsurface flies in Michigan.