Goss's wilt on corn
Authors: Byamukama, E. and Yabwalo, D.
Causal Organism
Goss’s bacterial wilt and leaf blight of corn is caused by a bacterial pathogen Clavibacter michiganensis nebraskensis (CMN).
Symptoms and Signs
Goss’s bacterial wilt and leaf blight also known as bacterial leaf freckles has two disease phases as the name suggests, the leaf blight phase and the wilt phase. The leaf blight phase is the most common one. The leaf blight phase is characterized by long, tan-gray lesions. These lesions have dark, discontinuous water soaked spots (freckles) and these are held against light, transparent spots can be seen. The freckles serve as distinguishing symptom of this disease from look like such as Northern corn leaf blight. oblong tannish lesions that are not limited by leaf veins. The typical sign of the CMN is bacterial streaming when an infected tissue is dropped in water and observed under the microscope. The wilting phase develops when younger plants (up to V6) become systemically infected. Young corn plants with Goss’s wilt may be mistaken for drought or fertilizer burn.
Disease Impacts
Goss’s leaf blight and wilt can result in severe yield losses. Plants infected young may not produce an ear and plants whose leaves die prematurely have light kernels.
Life Cycle and Epidemiology
CMN survive on corn residue and also other grass hosts such as grain sorghum, green foxtail, barnyard grass and other grasses. CMN can be transmitted through seed but the most important source of inoculum is infested corn residue. The bacteria is splashed onto corn leaves and enters the plant through natural openings and through wounds created by insect feeding, hail, or sand blasting. Infection is favored by under wet and warm conditions.
Management Approaches
• Plant Goss’s bacterial wilt and leaf blight resistant hybrids. Select hybrids with the highest rating against the disease.
• For fields with a history of Goss’s wilt, use tillage to burry corn residue where practical.
• Rotation with broadleaf crops will help to reduce the inoculum
Other Online Resources
Crop Protection Network. Goss's wilt of corn. https://cropprotectionnetwork.org/encyclopedia/corn-disease-management/foliar-diseases/gosss-wilt/
