Check stands for seedling blights

Every season is different and has different challenges and opportunities. Most farmers in northern Ohio were able to plant early but southern areas remained overly blessed with too much rain. After planting, it turned cold and the seedling blights had their chance to attack. Early planting has benefits but also risks if it turns wet and cold during emergence. Corn seedling blights can cause considerable stand losses as we saw in some areas last year. Recent cool and wet weather patterns create ideal weather conditions for the seedling fungal diseases.

• Seedling diseases are favored by wet and cool soil conditions (50 to 55 F) after planting. Corn planted early or in no-till ground is more susceptible to these diseases. Recent cool and wet periods were ideal for the disease organisms that cause seedling blights.

• The pathogens that infect corn seedlings are species of Pythium, Fusarium and Rhizoctonia. These fungi over-winter in the soil or plant debris.

• These fungi can infect a substantial portion of the developing root system, including the mesocotyl which attaches the primary roots of the seed to the developing seedling, the primary or seminal roots.

• The roots appear brown and become soft-rotted and water-soaked. Outer tissue of the plant is infected and may peel off. Yellowing and stunting of the plants may occur.

• The seeds of infected plants start rotting and become mushy and the seedlings turn a brownish color. Survival of seedlings depends on healthy germinating seed which should remain firm and mesocotyl should be white.

• For the future, crop rotation may be helpful in reducing inoculum levels, but some fungi can affect both corn and soybeans. Use of the best seed treatments available is strongly recommended if you are going to plant early since it can turn cold and make the young plants prone to the disease organisms.

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