white powder mold or mildew on my clones

i have 5 clones that i transplanted into some bigger cups after they were rooting well....now 2 weeks later they are growing and looking awesome,,,but ive started seeing white powdery stuff on leaves, and on the stems,,, how do i eliminate this problem..i have had them in my sunporch with windows open for a bit of ventalation, ,,it has been a little rainy out the past 2weeks, so im thinking mabey to much moisture in the room, but im not to sure, just want the problem gone ....please help..

spray with neem oil.

there is sulfur powder, but your supposed to apply that at the beginning of the spring to the end.

ok,,will try it out,,thnks.