You should be able to turn the power down, which will give a shorter output time.
Actually, the Photogenic monolights have longer (slower) flash durations as their power levels are reduced...this is also the case with Alien Bee monolights, and a few others.
http://www.photogenic.com/download.aspx?type=manual&id=25
The shutter speed you are using is 1/320 second, and the stated max speed on a 1D Mark III is 1/250 second, so I am assuming that the speedlight flash is defaulting to an FP or high-speed synch setting--which is actually a long, slooooooow series of micro-flash bursts, and not a single,discrete flash burst. High Speed Sync will lead to blurred motion on all sorts of stop-action motion scenarios--birds in daylight, water drop scenes, all types of rapid motion will be blurred if a Canon or Nikon flash is operating in High Speed Sync or Focal Plane Sync mode. So, the flash synch shutter speed of 1/320 doesn't make a lot of sense to me.
I am not sure why this scene needs three lights. Regardless, with the Photogenic monolights, the shortest duration flash will be at Full power,not at a fractional power level. Not sure how the 580 is being set either--if it is in a manual mode at higher power, its flash duration could be INCREDIBLY SLOW!!!! In actual measurements, a 580 EX-11 at Full power could drag your shutter speed down as slow at 1/169 second with the sensor .5 feet from the scene, and at 2.0 feet, a 580 EX-II at Full power can be as slow as 1/177 second.
Again, the actual flash durations can be pretty slow
The Rod And Cone: Flash Durations for Canon 580EX II and Vivitar 285HV and so, unfortunately, I think the idea that the problem is not the equipment is in error--I would say it *is the equipment* that is causing the blurring on the dropping strawberry. Or, in another way of looking at it, the *manner* in which the equipment is being utilized is causing a problem.
If you look at the rodandcone page on speedlight duration, there are some tips and comments there on how speedlight durations actually change,depending on how far the sensor is from the subject--at close-up ranges with a lot of white in the background, the durations are much,much slower and longer than when the sensor is farther away,and of course, the Photogenic monolights get slower at lower power levels, while the speedlights get shorter at lower power levels.
So, looking at everything, it seems like there re a couple of likely culprits. What does the scene look like exposed with NO flash?? Doesn't f/22 at 1/320 yield a pretty dark scene? The blur on the berry looks very well-exposed and bright; individual seeds are visible, and it's not "Dark", so it looks to me like basically, too long of a flash duration, and I am wondering about the 580 and the 1/320 speed shifting the camera to the High Speed Sync mode,and causing the rapid-fire 80 hertz (??) HSS burst which allows the dropping berry to blur.