Diplodia Stalk Rot
About the Disease: The Diplodia Stalk Rot is caused by fungus. This is characterized by the formation of few lesions in brown color.
Symptoms: The most obvious symptom and one of the first symptoms that is observed is the gray colored leaves. The leaves turn almost grayish green in color. Apart from this symptom, there are brown colored lesions that are observed throughout the stalk. The pith of the plant also gets disintegrated. Then it becomes discolored. The stalk then completely breaks apart.
The black bumps called Pycnidia will be formed below the epidermis on all the internodes regions. Thus you need to inspect the plant for the disease condition in few key areas like the nodes, internodes and the stalk. The symptoms are not so different from the symptom caused in the Gibberella stalk rot. In the case of Giberrella rot, there will be pink coloration of the stalk. This is not observed in the case of Diplodia stalk rot. Instead you can observe few white colored mycelium on the stalks. Along with this pycnidia might also be seen in large numbers. The lower stalk gets affected badly. When the inner regions of the stalk are analyzed, it is found that the tissues are shredded. There are also many dark specks.
Pathogen Involved: The main pathogen that is involved in causing this disease is the Diplodia maydis
Time of Occurrence: Once pollination gets completed, there is a chance for the occurrence of the disease.
Conditions Favoring Disease: Warm weather favors the growth of the fungi and the progression of the disease. When corn is continuously grown in the same place, it might also be a condition that favors the disease. Stress can also be an important inducing factor.
Disease Management: There are several easy ways of controlling this disease. The Diplodia Stalk Rot can be prevented if too much of overcrowding of the plants is avoided. A proper study has to be initially conducted for the selection of the resistant hybrid variety and the susceptible ones.
When all the plants cultivated are the resistant varieties, then there will be less chance or rather no chance for the entry of the fungus into the plant parts. The effort for finding the hybrid variety must be more. Apart from this crop rotation can also be done. Plowing has to be done regularly. The moisture content in the soil has to be maintained at the proper level. When there is too much, this can support the growth of the fungus.