Plant Health Problems
Kale, like collards, is a non-heading form of cabbage grown for its edible foliage. See Crucifers for a detailed discussion of the common diseases of this host.

Insect Problems:

Some of the insects that injure cabbage also feed upon kale. See Cabbage.

Turnip aphid, Lipaphis erysimi.
This aphid infests kale. See Aphid fact sheet.