You should also scout fields with a large number of non-pollinated ear tips or have significant European corn borer or bird damage since this ears are also prone to Gibberella infection. These mycotoxins are especially important to swine and other livestock producers since they can have a detrimental affect on their animals. Zealalenone is an estrogen and cause reproductive problems such as infertility and abortion in livestock, especially swine. Another common ear rot this year is Fusarium Ear Rot. Unlike Gibberella, Fusarium infected kernels will be scattered around the cob amongst healthy looking kernels or on kernels that have been damaged for example by corn borer or bird feeding.
Silks are susceptible to infection during the first five days after initiation.
Of the three primary ear rots that occur in Ontario Diplodia ear rot caused by Diplodia maydis is the usually the least common. Having said that we are seeing more Diplodia ear rot this year since it favours cool, wet conditions through grain fill but in no way to the same extend that surrounding states such as Ohio are experiencing. The characteristic ear symptom is a white mould that begins at the base of the ear and will eventually cover and rot the entire ear. These reproductive structures are where new spores are produced. Unlike Gibberella and Fusarium, Diplodia does not produce any known toxins.