Field Crop Disease Management

Bulletin 631-98

Table 1. Comprehensive Disease Control Program for Field Crops

1. Select varieties and hybrids resistant to the most common or economically important diseases in specific fields. Resistant varieties with yield potential, good agronomic characteristics, and excellent quality are available for most field crops. Refer to Ohio State University Extension performance trial evaluations for resistance ratings of specific crops.

2. Plant only the highest quality, disease-free seed. Be sure that the seed is well-cleaned, has a high germination percentage, and is guaranteed to be genetically pure to the variety or hybrid stated on the label. Where appropriate, use seed-treatment fungicides to control diseases. See OSUE Bulletin 639 Seed Treatment for Agronomic Crops for specific crop recommendations for seed-borne and soil-borne diseases of concern.

3. Plant when soil temperature and moisture are most favorable for specific crop seed germination and seedling growth of the crop planted. Planting in roughly prepared soil, under conditions which are too cold or warm, or too wet or dry increases the chance of seed-rot and seedling-blight diseases. Seed treatment fungicides will often help stand establishment when seeds are planted under environmental conditions that favor pathogens.

4. Follow a good crop-rotation sequence. Avoid planting the same crop in a field year after year, since monoculture promotes build up of pathogen populations. Always alternate to non-host crops in the rotation sequence and provide sufficient time between susceptible crops for the population of disease organisms to decline.

5. Destroy residues of the previous crop by tilling as far in advance of planting the new crop as possible. Many disease organisms that survive from year to year on crop residues can be eliminated by incorporating the residue into the soil. Farmers using reduced tillage systems need to pay particular attention to using adequate crop rotations.

6. Plan a well balanced soil fertility program based on a soil test. Proper soil pH and adequate amounts of nitrogen, potassium, and phosphorus in proportions required by the crop species will promote healthy plant growth. Avoid high salt accumulation from excessive manure or organic-waste applications. Maintain as high a soil-organic matter content as economically feasible.

7. Control weeds that compete with crop plants for nutrients and moisture. Weeds can serve as alternate hosts for pathogens thus increasing pathogen populations. Weed may also result in higher humidity within the plant stand, favoring disease development.

8. Maintain plant vigor by controlling insects. Insects may transmit virus or bacterial diseases or injure plants providing entry points for pathogens. Insect feeding injury can also reduce plant vigor.