Vegetable crops in the crucifer family, grown for their edible leaves include collards, kale, mustard, turnips, and turnip x mustard hybrids. These cool-season crops are well adapted for spring and fall production in Oklahoma. While most of the production is for processing, both processing and fresh markets demand high-quality produce free of blemishes. Diseases are important factors limiting the production of leafy greens. Diseases mainly cause damage by reducing crop quality. Severe disease development can reduce quality to the point where the crop is unmarketable.