mealybugs can cause powdery looking white spots. I have never seen them on weed but I had a big problem with them on a coffe bean tree I was growing indoors.

Rub the white stuff between your fingers. Is there a tiny worm-like critter in there?
stinkyattic Reviewed by stinkyattic on . white stuff on my seedlings hey can someone help me? on some of the leaves, there is some little white dots on it. sort ove looks like dots of flour. whats causing this and how can i fix it? Rating: 5