TRAIL — A 14-inch trout rolls on the surface of the upper Rogue, and fly-fisher Chuck Campana is prepared to see whether this fish wants one more serving of the bug world's equivalent of a T-bone steak.

TRAIL — A 14-inch trout rolls on the surface of the upper Rogue, and fly-fisher Chuck Campana is prepared to see whether this fish wants one more serving of the bug world's equivalent of a T-bone steak.

Campana casts an imitation salmonfly — a concoction of foam, feathers and thread that's the size of a hummingbird and about as heavy.

The fly plops on the surface with all the stealth of a plane crash. And like an obese kid headed for fat camp, the trout can't resist one last mega-meal.

Campana rarely fishes for critters this small, and he rarely uses flies this big.

"It's pretty enjoyable," says Campana, 78, of Sacramento. "I'd be steelhead fishing if it wasn't for this. I've been coming here more than 25 years just for this. That's how much fun it is for me."

This is the magic of the salmonfly hatch, a combination of massive flights of macro-bugs and binging rainbows that turn steelheaders into trout bums for one magical month on the Rogue.

Salmonflies now plying the skies over the far upper Rogue are the biggest of the water-born insects here, and their annual hatch triggers a feeding frenzy in the Rogue Basin's trout waters that is unmatched by any other hatch.

It's all about casting huge, orange-bodied dry flies to get rainbows to pick the artificial from among the rafts of real flies up to 21/2 inches long that are floating on the surface.

"The best part about it is the take on the top," Campana says. "The grab is the whole thing."

Their presence in June — between the winter and summer steelhead runs — makes them a perfect bridge for steelheaders segueing from one addiction to another. It's also a hatch of choice for the myopic trout-lovers relishing a change from casting tiny dry flies or nymphs.

"It starts Memorial Day weekend and ends roughly the Fourth of July," says Dave Roberts, an Eagle Point fly-fishing guide who has tossed salmonflies toward Rogue trout for 30 years.

Roberts this week is fishing out of his driftboat along the upper Rogue, offering salmonflies to resident rainbow, native cutthroat trout and a few early-run summer steelhead.

"It's easy fishing and it's fun," Roberts says. "Who needs a better reason than that?"

Others are practicing catch-and-release fishing for resident wild rainbows in the Applegate River, a major Rogue tributary. The far upper end of the stream below Applegate Dam has been best.

"I've had people come in here and clean me out of stoneflies just for the Applegate," says D.J. Macdonald, owner of Southern Oregon Fly on West Main Street in Medford.

But most salmonfly disciples focus on the upper Rogue's so-called "Holy Water," the impoundment between Lost Creek dam and the Cole Rivers Hatchery water intake.

This eight-tenths-of-a-mile stretch is stocked with thousands of rainbows annually. It's all catch-and-release fishing, with only traditional fly-casting gear and barbless flies.

It also is the salmonfly's Mecca.

Bugs that hatch in the Rogue fly upstream until they hit the dam's edifice, and the stoneflies hover the thickest at the dam's water outlet.

Fly patterns start with the Rogue Foam Stone, a size No. 4 fly that emphasizes the salmonfly's orange body and pterodactyl-like wings that give the bug its scientific name, Pteronarcys californica. The smaller and more sparse Clark's Stonefly is another Rogue Basin staple, as is the "Stimulator" — and even a dry golden stonefly as a change of pace.

But to match this hatch, anglers here favor the Rogue Foam Stone.

"If you go out to the Holy Water and there's 20 guys fishing stoneflies, 18 of them have this fly on," Macdonald says.

Stoneflies spend most of their lives underwater filter-feeding on organisms. Just before they hatch, the nymphs crawl out of the water, dry their wings and fly to a nearby tree for mating.

The females, which are larger, then fly over the river, splat on the surface and broadcast their eggs.

The action is hottest in the beginning of the hatch and right after the bugs stop flying, when the trout are craving one more T-bone for the year. Mid-hatch is the slowest, with trout having no room in their bellies for another fly.

Fly-casters can generate a little trout buzz by committing the normally high sin of letting their flies slap the surface over the fish. But the fly must drift drag-free or the trout will suspect the T-bone might have a hook in it.

"They won't tolerate a drag," Campana says. "It has to be drag-free."

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com.