Pushing Your Yields Past White Mold Pressure

Don't Let White Mold hurt your yields

White mold is an issue that can creep up on growers and limit yields if not accounted for. In a report by Minnesota Farm Guide, Extension Plant Pathologist Damon Smith from University of Wisconsin says that for every 10 percent increase of white mold in soybean plants at R7, growers saw yield reductions of 2 to 5 bu/A. At harvest, those losses can be a significant loss. But before solving the issue, the first step is being able to understand your risks, identify the disease and how you can effectively limit infection damage from year to year.

Know Your Risks

Plants are generally more at risk to white mold at early flowering, or the R1 growth stage. The disease typically thrives in wet, cool, humid environments. These conditions are common early in the season, though they can redevelop later in the season after the summer’s heat recedes. Extended wet periods without large changes in temperatures can also increase risk. Growers planting acres with past issues need to pay extra attention, because the resting bodies, or sclerotia, of the causal pathogen can survive for long periods in the field.

In addition to weather conditions, Michigan State University says growers on no-till operations have higher risks of disease, as white mold can survive in soil surfaces for long periods of time if following crops are also susceptible to white mold.

Other contributing factors according to University of Wisconsin are:

  • Varieties that are bushier, forcing an earlier closing canopy.
  • Poor weed management of broadleaf weeds.
  • Distribution of disease throughout the field can change due to topography with areas that have poor drainage, are adjacent to tree lines and other natural barriers that impede air movement.

Identification is Key

In order to quickly take care of infection problems from white mold, it’s good to know the symptoms of the disease. That way, regular scouting can catch problems in their infancy to limit yield loss and protect plant health.

soybean pod infected with white mold

White Mold

Purdue University Extension researchers tell growers to look for the following signs:

  • White, fluffy, cottony growth on the outside of the stem and on the pods.
  • Wilted leaves and stems that appear bleached, along with tearing of the stem tissue.
  • Sclerotia can also be found on and inside plants that have been infected by white mold.
A soybean pod and stem infected with white mold.

Prevention and Proactivity Best

Timely foliar fungicide applications help protect soybean plants from fungal diseases, including Septoria leaf spot and white mold. For growers, a fungicide decision is a matter of considering production needs, past history in the fields, commodity prices, proper timing and risk management.

Delaro™ fungicide offers an unmatched broad spectrum control. Its advanced formulation delivers best-in-class dual mode of action residual and improved plant health. To manage white mold, the ideal time to first apply Delaro is prior to disease development, at R1, followed by a second treatment at R3 or R4. Disease-susceptible cultivars and seed soybeans are most likely to benefit from a Delaro application. For cost efficiency, Delaro can be tankmixed with insecticides and applied in the same trip across the field.

Before applying any fungicide, please read the entire label for the best possible results and to confirm that the product is effective on the disease you need to control. Not every product is suitable for every situation, and correct application technique will ensure the best results.

To limit yield loss in soybeans from other common issues, you might be interested in reading:


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