Question
We've noticed this under our crabapple tree and also that plants we put in under that tree do not do well. It doesn't matter if we plant snapdragons, petunias, black-eyed susans, etc.; they all wither and die. We don't think it to be a problem of watering too much or too little. We live in the northeastern section of Ohio.

Answer
Hi Jim, There may be other reasons that plants die under the crabapple, but since the fungus is there, that's the first place to start.  Go see your local independent garden center for a fungicide approved for use in your area.  Products that contain either PCNB, Eagle, Cleary's 3336 or Bayleton would be good ones to try and you may have to try several and apply several times over the course of a year to find which product works best.  Take a sample with you.  The nurseryman may be able to identify which fungus it is and know immediately which product to use.  Jim