Crazy top, named for the odd formations of the leaves or tassel due to hormonal effects of the disease, is typically found on corn plants that were submerged for a few days early in the growing season. A description of the disease and of its symptoms can be found at http://bulletin.ipm.illinois.edu/pastpest/articles/200220c.html
While a lot of corn was submerged during early growth in Illinois this year, we haven’t been seeing a lot of this disease. It may be that corn in many fields was submerged so long that growth never recovered, making plants a poor host for the disease. The disease may be more likely to show up in parts of fields where the water rose then went away within a few days, after which the crop grew normally.
Some researchers at the USDA-ARS lab in Peoria are looking for infected plants so they can isolate the fungus that causes this disease. If anyone has found infected plants that they could travel to sample, please send me an email and I’ll put you in touch.