What can I do about potted cucumbers...

Powdery mildew is caused by the fungus Erysiphe cichoracearum. It attacks cucumbers, muskmelons, squash, gourds, watermelons, and pumpkins. In dry seasons, the mildew can cause premature death of the leaves. When most of the foliage is attacked, the plant is weakened and the fruit ripens prematurely. Fungicide applications should begin at the first sign of powdery mildew and again after ten days.