With  this on again, off again; warm and then
wet cool weather, this is prime for tomato and
potato late blight.  We haven't seen it yet but
the weather is perfect for it.
Keep foliage as dry as possible -- hope that the
rain quits, only use drip irrigation.  Try NOT to
walk down the tomato or potato rows while
the foliage is wet.
Trim the plants, sanitize the clipper so there
is good air circulation.
Use copper or organic Serenade to protect the foliage.
Cover with a small plastic cloche.