The International Maize
and Wheat Improvement Center (CIMMYT) offers a test version
of an online diagnosis tool for identifying maize production
problems. The website, called “Maize
Doctor”, contains a collection of information about
cultural management practices on maize, as well as taxonomic
keys for helping identify its pests and diseases.
http://www.cimmyt.org/english/wps/maizedoctor/index.htm