Diplodia Stalk Rot

Diplodia maydis

Diplodia stalk rot is caused by a fungus that infects stalks and ears of corn after silking. It has been known to reduce yield potential, as it sometimes results in lodging.
Diplodia stalk rot favors warm and wet conditions, surviving in infected crop residue. Spores are spread through splashing rain or the wind. Diplodia stalk rot is most dangerous in times where plants are stressed by other diseases or insect injury.
Symptoms usually begin to show between 2 and 3 weeks after silking, appearing as grayish-green coloring on the leaves. This eventually turns dark brown. The base of the stalk is covered inside and out with tiny black bumps. This causes a straw-brown discoloration in the lower nodes, and the pith of the stalk begins to disintegrate. This causes the stalk to easily break, often resulting in lodging.
Diplodia stalk rot can cause significant losses in yield in some cases. It has a lot of potential to cause harm in the case of repeated corn and no-till fields.
Tillage is very important for breaking down infected corn residue. Reducing stress of plants as much as possible will allow for a healthier, more resistant crop.
Controlling stalk-boring insects with pesticides and maintaining a balanced soil pH through the use of fertilizer can reduce the risk for a diplodia stalk rot infection.
To reduce the risk of infection, crop rotation is very important. If continuous corn is necessary, rotating corn genetics can be helpful. Choosing hybrids with resistance or high stalk strength is another great way to avoid yield loss in corn.