unknown pest or desease?

[ninilie]

First I found my potato plant covered in what looked like spider webs. I sprayed it with water but the next day the plant still died. Next I noticed it on a tomato plant, same thing looked like it was covered in spider webs. The fruit of the plant got spotted and the they never ripened and the plant died soon after. The fruit stayed small and became kind of hard. Now several of my tom plants have this web on them. Anyone ever had anything like this happen? I do not see any bugs on the plants at all. Also it has been super hot here like in the 100's for two or more weeks.