Managing white mold in soybeans requires careful consideration of various factors, including the decision to apply fungicides, selection of effective fungicides, and proper sprayer equipment and operation. Here are key points to keep in mind:
1. Disease Management Approach: Fungicides are part of an integrated approach to managing white mold and should be used in combination with other practices such as using partially resistant varieties, implementing wide rows, adjusting planting rates, managing irrigation water, and employing appropriate tillage methods.
2. History of White Mold: Assess the presence of white mold sclerotia in the soil, as they can survive for several years and contribute to disease development.
3. Soybean Canopy Density: Factors like narrow rows, high planting populations, early planting dates, and high fertility levels can result in a dense soybean canopy, increasing the risk of white mold. Consider these factors when managing crop density.
4. Optimum Timing: Fungicide application should occur between the R1 and R3 growth stages to protect flowers from infection. Application at R2 may also be effective. Use tools like the Sporecaster phone app to determine the appropriate timing.
5. Environmental Conditions: Cool and continuously moist topsoil for seven to 10 days before the R1 growth stage, along with cool ambient air temperatures and continuous foliage moisture, create favorable conditions for white mold infection.
6. Fungicide Effectiveness: Certain fungicides have shown good to very good management of white mold when applied correctly, including Approach 2.08SC, Endura 0.7DF, Lektivar 40SC, Omega 500DF, and Propulse 3.34SC.
7. Sprayer Equipment and Operation: Optimize droplet penetration and plant coverage by following these guidelines: apply 15 to 20 gallons of water per acre, maintain nozzle pressure around 40 psi, control ground speed at 10 mph or less, use appropriate nozzles for large, dense canopies, and select nozzles that generate fine to medium droplets (200-350 microns).
8. Realistic Expectations: Understand that fungicides are not a guaranteed solution for white mold control, and their effectiveness can vary from 10 to 80 percent in research trials.
By considering these factors, farmers can make informed decisions about fungicide use, enhance disease management practices, and minimize the impact of white mold on soybean crops.
Photo Credit: istock-urpspoteko
Categories: Michigan, Crops, Soybeans