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Corn Diseases - Bacterial Stalk Rot


Figure 10.40Corn plant infected with bacterial stalk rot.

Bacterial stalk rot is caused by Erwinia carotovora strains.

SYMPTOMS:

The disease usually starts mid-season. Plants suddenly lodge and internodes close to the soil line are discolored and water soaked. When overhead irrigation is used, a top rot can follow quickly during times of fast vegetative growth. When infected stalks are cut, the tissue is slimy and has a foul smell to it.

DISEASE CYCLE:

E. carotovora survive in old stalks above-ground. The bacteria are spread in water and infect the plants through natural openings and wounds. The disease is most prevalent in areas with high rainfall, or where surface irrigation is used from pond or lake water. Surface water running into ponds and lakes can carry soil and the bacteria with it. During overhead irrigation, the bacteria are washed onto the stalks and leaves where they then can enter the plant through openings. Flood irrigation can carry the bacteria to the base of stalks. High temperatures between 90-95°F and high relative humidity increase the disease.

MANAGEMENT:

Good cultural control practices in areas where the disease has occurred are best.

      • Plow plant debris like stalks deep into the ground
      • Avoid using surface water for irrigation (flooding or overhead).

Images:
Image 1, Howard F. Schwartz, CSU, Bugwood.org