Yes, go with nymphs. I've had the same problem-summer white suckers ignore pretty much everything- and in fact the only thing I've ever caught them on in the summer is nymph flies. I've done best with flashback pheasant tails, Prince nymphs, and copper johns in size 12-18. Sight fish with an indicator and as soon as you see the fly touch their lips, hit 'em hard, because they literally will drop it in a fraction of a second. Another thing: don't be afraid to hang the nymph well above the bottom. White suckers are notorious for constantly eating crap off the bottom- hence the name sucker- but in truth, they're usually suspended, and they'll often rise several feet for something they want in slow, clear water even if they aren't.
It can take a while to figure out, but nymphs will almost always catch more whites than any bait once you do.
If the nymphs don't work buddy, what you have to do is run across the border into Mizzou and get yourself some quarter and half sticks. Then you tape them to a rock tie on a float with a small leader so you can drift them lit into the school of fish. Works like a charm ........ everytime LOL J/K bud, we haven't been out fishing at all, been stuck at work everyday last month, hoping to get down south again towards the end of August to try for river reds and flats. Good luck with the whites man I'm sure you'll figure them out you've been kicking butt lately!!
P.E.T.A. sucks!!! Plants are living things, too -- they're just easier to catch!
I pretty much agree with philaroman. Try to find some fish in a better spot. Most often suckers holding in slow featureless areas where you can see them are not very catchable. Try areas of shade, riffles, woody cover or rocks. More current is generally key this time of year.
You didn't mention what size hook you're using. I catch stationary ones in summer in a small creek where I can get above them and literally suspend my bait right at their nose. Sometimes this can take an hour to entice a bite. I use size 28 hooks and a small bit of worm. I have had luck with a piece of Berkley gulp maggot when they weren't reacting to the worm but the other guys are correct in the fact that they will "breathe" it in and spit it in about 1 second. The hogsuckers same technique, but it's always easier on fish that are moving about.
I've always had better luck in deeper slower water for them during the spawning run up here. I have caught a few in the riffles but it took a lot of waiting before one finally went for it, and they have a habit of swimming through my line and getting me snagged. Try a pool, or some slack water nearby. I've had success with worms on a slinky rig.
2017 Goals: Longnose Sucker (missed),Silver Redhorse, Pacific Salmons (Chinook, Coho), Brown Trout
Like RF was saying about getting above them, FP and I had great success fishing off a bridge over some stationary horses and suckers in pretty good current. We could see them from on top the bridge and kept flipping our rigs (crawlers) back and forth until we'd get it right in front of whatever species we wanted to get out of the school. They wouldn't move more then a couple inches so we had to drop it right in front of them, if it was off to the side or just a few inches down current of their mouths they wouldn't bother moving far enough to grab it, so we'd reel in and start over, then they would suck in the crawlers, but it was very light, so much so we were hooking them by sight when you'd see their lips move and not by feel.
I'm using size 16 nymph hooks with a small spilt shot about a foot above the hook.
2017 Undisputed Iowa Small Drum and Creek Chub Champion
I may just have to wait until the water rises because the deep holes seem to be barren. The water currently is incredibly low and fish are actually being found mainly in slow current areas that are 1-3ft deep, as that's where the suckers are still holding at. I tried philaromans method of bait but the cats still managed to find it first (they're voracious in this creek). I haven't been able to try nymphs yet and hope to be able to get out there with some soon.