grey sand-like particles on kale plants

[cracker]

All my brassicas were infected. All over the leaves, especially at the crown, were grey particles th e size of sand. The plants stank awfully

I cannot find any disease listed that cause these.
Can someone help?

[applestar]

Did you take pictures? Could you be talking about cabbage aphids?

-- here's a photo I grabbed off the internet:

http://entnemdept.ufl.edu/creatures/veg/aphid/Brevicoryne_brassicae03.jpg

[cracker]

Thank you, that is exactly what they are.