Repeat weekly or as needed. Found in numbers on underside of leaves, causing curling, distortion, and stunting. Spray or dust as soon as plants are set out. Use Malathion or Diazinon. Small black or dark brown spots on lower leaves.
Spots enlarge, leaves turn yellow.
Excessive leaf drop. Plant clean tubers. Rake and burn plant debris. Use Copper fungicide, Mancozeb, or Daconil 2787. Eventually, entire leaf blighted.