Field library

Purple Blotch

A fungus disease of the onion leaves and the seed stalk. It starts as small white sunken specks, then turns into big oval patches with a purple middle and a yellow edge. Badly hit leaves and seed stalks bend over and snap, the bulb stops filling, and it stays small.

How to scout

Look over the older outer leaves after a dewy night or a light shower, because the first specks show there, and the rings inside the patch are the sure sign.