I have a tomato plant with small raised shite bumps on the main stem, I dont know if I would call it a powdery mildew, but definate raised spots. |
What you describe might be stem cankers (a disease) or they could simply be calloused material - the result of injury or the natural healing over where a leaf was lost. It is difficult to tell without examining the plant. If it is a disease, a copper based fungicide should help. Wish I could offer more assistance! |