Q.leaves grey and mites on collards
The leaves on most of my veggies turn grey and on the collard greens there are clusters of grey tiny mites. Are they poisonous?
The insects are likely not poisonous, but you should wash and remove them prior to consuming.
Your plants may have Powdery Mildew, Spider Mites, or Mealybugs.
You can treat with Neem Oil, as it works as both an insecticide and fungicide. It is safe for people, pets and bees.
Here are some links for you.