Hi Richard, there are a couple of things that I think may have contributed to the lack of sharpness on this image.
The first is the shutter speed of 1/15 sec. My guess is, having just been on my hands and knees taking photos of fungi myself, that you were too low on the ground to use a tripod and even if you had the camera on a beanbag, 1/15 is very slow to get a sharp shot. A burst of flash would have made all the difference and would have added a little glow to the subject.
From the exif data above, I can see that you were using a 24 - 70 lens but not what focal length the photo was taken at. I'm just wondering if maybe you were a little too close to the subject for the autofocus to work properly? I too have this camera and lens and find that if I'm quite close, manual focusing is more likely to get a sharp image than autofocus. Just a thought but it might make all the difference.
Keep at it, practice makes perfect!