After about a month of excellent production, the new leaves on my three collard green plants are curling and puckering. It definitely starts in the center with new growth. I did not see any obvious pests. There is some sort of brownish rot in the center, which you can see in the second picture. I have similar symptoms on Red Russian Kale and Swiss Chard in other beds. I am considering trying a neem oil spray in case there are aphids. My research is not turning up examples of this symptom. I saw something similar on kale last year. I am located in Chicago, IL. Thanks for any advice!
Distortion of new Collard Green leaves
Brownish rot/disease/damage around the center/new growth
I think it could be Swede midge damage. The insect feeds on cole crops resulting in corky brown scarring near leaf petioles. Also one may see twisted leaves and may also leads to emergence of multiple heads or stems.