Q: What are the small white flies on the back of my collard leaves?

A: I wasn’t previously familiar with whitefly damage to collards bit it turns out that this is an important pest. They suck sap from the leaves, eventually killing them. Insecticidal oil, like neem oil, is effective if you are persistent about applying it. The easiest synthetic insecticide to use is acetamiprid (Ortho Flower, Fruit & Vegetable Insect Killer). Read and follow all labels.