Cress Bug

I have been placing fly pattern photos and recipes here in the past, ever since I started this blog in March 2010. I plan to continue this effort, adding to the number and diversity of fly patterns here, creating what will eventually become a Fly Pattern Dictionary. This Dictionary will contain of course classic wet fly patterns, (it already does), but I will also be adding drys, nymphs, streamers, and other fly patterns. Most of these will be flies that I tied, and there may occasionally be some flies from other tiers. I will be placing my original patterns here as well; they will be placed intermittently. I may do an occasional photographic step-by-step tying tutorial, but for the most part, this Fly Pattern Dictionary will contain fly patterns and recipes, and maybe a few fishing tips. I know, there’s already lots of that stuff like this on the internet already, but I think I have something to offer or I wouldn’t be doing this.

Most intermediate and advanced tiers can get the pattern by looking at a good photo, reading the recipe, and maybe asking a question or two. The comments / questions here are intended for my readers to use to their advantage. I shall endeavor to maintain and expand this project as time permits.

I will also be adding new Categories to facilitate the use of finding the information you want. Don’t forget to use the Search Tab!

The Cress Bug is my first “official” post in the Don Bastian Wet Flies Fly Pattern Dictionary.

Cress Bug, also known as an Isopod, though not to be confused with fresh water scuds. Scuds and Cress Bugs are different animals. This is a profile view. Note the heavily picked dubbing; this simulates the legs.

Cress Bug, view No. 2, slightly elevated camera angle. Here you can see the smooth top / back of the bug, an imitative effort to mimic the shape, appearance, and silhouette of the naturals. Doesn’t that 6/0 Uni-thread rib look like hawser cable? The benefit of macro-photography.

Cress Bug – top view. Size #14 Montana Fly Company Hook, #7026 – #14, 1x long, 2x heavy wire. The heavily-picked dubbing imitates both the legs and the natural wide body shape of the cress bugs.

Cress Bug

The ingredients are listed in the order in which they are tied in. This is basically a Cress Bug pattern of my friend, Dave Rothrock, but I added the scud back on top to make the pattern look a bit more realistic. It does make the fly look “more realistic” but for fishing effectiveness it’s not necessary. Sometimes we tiers add extra stuff to our patterns just to make the fly look better, whether the fish care or not. Come on, now, you know it’s true. 😉

Hook: Standard wet fly or 1x long nymph hook, sizes #14 to #22. I have also dressed this Cress Bug pattern (omitting the shellback) on size #20 and #22 scud hooks with successful results, especially in summer when the water is low and clear.

Thread: Danville Flymaster 6/0, #60 Olive

Median Stripe: Dark Brown Uni-thread 6/0

Rib: Dark Brown Uni-thread 6/0

Shellback: Scud back, 1/8″. I tied this fly with tan but you could use clear.

Body: Haretron Dubbing – this is a mix I blended myself by hand for the current order of a dozen mixed sizes I’m tying. I used #3 Gray, #5 Light Olive, #16 dark Brown, and #18 Ginger. There is no official ratio for this mix; I’m not that technical. I just took a pinch of this ‘n’ that and blended it together to get what you see as a darker olive-brown-gray. It’s mostly olive and gray with less of the other colors.

Head: Tying thread

This is a staple fly on any limestone stream where Cress Bugs naturally occur. There would be some benefit to its use on freestone water as well, but I’ve never tried it because other patterns usually work.

Tying the Cress Bug:

Step 1: Start the tying thread at hook eye, wind and stop at the hook point. Attach the two strands of ribbing and median stripe thread. Wrap slightly past the barb.

Step 2: Wing the thread forward to the hook point, attach the scud back for the shell. After securing the scudback, wind back to the end of the body, stretching the scud back in the process.

Step3: Apply dubbing, heavily. You are making a robust body, football shaped. Wind the dubbing, almost to the hook eye, making the body larger in the middle half. Haretron dubbing as opposed to rabbit fur produces better density of the picked-out effect. The addition of the Antron essentially increases the underfur component of rabbit fur.

Step 4: Using a .30 caliber bore brush (available at your friendly local gun shop), brush from the top center of the body toward each side on a slight downward angle. This makes a body as if you used a dubbing loop, but in a fraction of the time. Cool, eh? :mrgreen:  Barry Beck demonstrated this tool in a fly tying class where I was assistant instructor in 1990 when I used to work for he and Cathy. This effort will produce a full spread of dense, picked-out dubbing.

Step 5: Trim the edges of the dubbing with scissors, cutting parallel to the body. This is where you find out if your scissors need to be sharpened. You want a body almost 3/8″ wide on a No. 14 hook.

Step 6: Pull the scud back forward, secure it with three wraps. Stretch the scud back and cut the excess.

Step 7: Pull the thread median stripe forward, keeping it top-center on the scud back. Don’t forget. A common mistake when I’ve taught this fly in classes is to either forget to attach it, or forget to bring it forward. Trim excess.

Step 8: Wind the rib, trim excess, and whip finish the head. Imitatively speaking you could make lots of wraps, but this makes it difficult to pick the dubbing out. Five ribs are best. Pick the dubbing between the ribs, then you’ll need to trim the sides once more.

I could tell lots of cress bug stories, but I’ll just tell my favorite one. One day while fishing in late June on Spring Creek, Pennsylvania, I spotted a feeding – nymphing trout in a shallow seam near the bank, along the edge of a riff. It was about 10:00 AM. The trout was about 18″. So I wanted to catch this fish. I was using a Cress Bug. I cast over there, made a few drifts, hooked the fish for about one second…and the hook pulled out. In less than five minutes that trout started feeding again. I tried the Cress Bug again, but he was suddenly smarter. I tried a number of other flies, casting not only to that trout but to other areas. I caught several fish in this time but couldn’t get that big brown to take again. I remember noting on my watch that exactly one hour had passed since I started fishing. I figured why not, he was still feeding, so I tied the Cress Bug on again. Same one he hit before. I guess his memory faded because he ate that Cress Bug again, but the story ended differently this time because I netted the fish.

One of the most important factors in Cress Bug imitations is to obtain a wide-from-the-top, flat-from-the-side profile of the fly. Unlike scuds, which are more akin to fresh water shrimp, cress bugs have no mobility of their own when adrift. Consequently the best method of fishing a cress bug pattern is with standard dead-drift nymph tactics. I use some type of indicator, which type depends on the level, clarity, and water type I’m fishing. Because of the heavily-picked dubbing, this fly has an almost neutral buoyancy in the water and needs at least one small split-shot even with the shallowest water in your target zone to get the fly submerged. This is also one fly that exemplifies one of my nymphing mantras: Not all nymphing is bottom-bouncing. Trout will often take cress bugs when they are suspended in the water column, so drifting at various depths can be productive.

Customer order of a dozen Cress Bugs to go. Assorted #14, #16, #18 – 1x long hooks. Ready for trout!

6 comments on “Cress Bug

  1. Kelly L says:

    Don, a fly pattern dictionary would be spectacular. I love the idea. I have never seen a Cress fly before. It looks very productive, and buggy!

    • Don Bastian says:

      Hi Kelly!
      Thanks for your encouragement! I’ll have to get a photo of the real bug next time I go to Spring Creek, hopefully soon. That can be done there by picking up almost any rock.
      Cress Bugs are isopods; they are the aquatic version of those things called Pill Bugs or Sow Bugs that crawl around under rocks in your yard. Also called a Hog Louse. My dad called them Stone Azels when I was a kid…I still do because of that…

  2. Kelly L says:

    The pill bug is what we used to call a Rolly Polly, when I was a kid. I don’t guess I have noticed the aquatic version.

  3. Bruce says:

    Hi Don, this is a question about your cress bug.
    Because of color variations on my computer monitor I’m not sure what the dominant color of your cress bug is. Is it more gray, light gray, etc.? I’m always tinkering with dubbing trying to match the Spring Creek cress bug colors. Hope you’re well, Bruce

    • Don Bastian says:

      Hi Bruce;
      This pattern is more of an olive shade, with some gray. I usually mix my own cress bug dubbing from 2 – 3 colors. I like the Haretron, because of the Antron mixed in; makes for better “picking.” After picking the dubbing out on the sides, you clip it parallel to the body, leaving it extend to develop the flat shape. Olive brown, gray, and light olive can all be used. I like to carry cress bug patterns in at least two color shades…light olive, and dark olive-gray. Thanks for your comment!

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