Cause A deficiency in the minor, nonmobile element boron.
Symptoms A necrotic cross-hatching inside the leaf petiole. Young leaves turn brown and die, resulting in a rosette of small dead leaves at the top of the beet. In the fleshy root, internal and external black spots of necrotic tissue develop.
- Apply boron to the soil with the fertilizer or separately at 1 to 2 lb ai/A.
- Applying 1 lb/A actual boron as a foliar spray twice in midseason also gives good control.