Crazy top of corn

Crazy top is caused by infection of Sclerophthora macrospora, an oomycete pathogen. Crazy top-affected plants are distorted and/or stunted. The leaves below the tassel may proliferate, resulting in a very bushy appearance of the top of the plant, which lends this disease its name. Internodes may be short or long; there may be a proliferation of ear shoots, leaves that are narrow and strap-like, excessive tillering, or a complete lack of ear and tassel formation.

Crazy top is more common in fields that are flooded early in the growing season. Proper soil drainage will reduce the risk of infection. Plant tissue distortion characteristic of crazy top. Image: A. Sisson

Crazy top symptoms include excessive tillering and shortened internodes. Image: A. Robertson