Two years ago I grew zukes and had some wood chips mixed in the soil around them. The wood chips caused the zukes to die with in a few weeks! None of the 6 plants survived so I now watch to many wood chips! The wood chips seem to also bring bugs!
How's the health of the plants? Green, yellow, puny? Did you grow them in the same wood chip bed? Wood chips on the surface is ok, but mixed in is a bad idea. You may have been able to compensate by adding a high nitrogen fertilizer.