Pushing Your Yields Past White Mold Pressure
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.
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.
To combat white mold infections and other diseases, Bayer recommends treating soybeans soon after initial flowering, or R1, with an application of Proline® fungicide. It has shown to be a very effective tool in the management of white mold, especially when coupled with a later fungicide application.
A best practice following an application of Proline is a follow up spray of Stratego® YLD fungicide. In this 2-spray approach, Stratego YLD protects the leaf canopy from foliar diseases, while Proline protects the lower parts of the plant. Stratego YLD features the latest in triazole technology combined with strobilurin chemistry for soybeans. It offers two modes of action providing both preventive and curative benefits and systemic movement for broad-spectrum, long-lasting foliar disease control and higher yield potential. In trials where Stratego YLD was applied alone at early pod set, around R3, yields increased on average between 3 and 4 bu/A versus untreated soybean plots.
For added protection from insects, growers can also tankmix Stratego YLD fungicide with a powerful insecticide like Leverage® 360. Applications like this can help lower costs, improve yields and increase ROI by reducing the number of passes needed to ensure crop protection. In trial tests, 90 percent of growers that applied Stratego YLD tankmixed with Leverage 360 at R3 saw a positive yield response, increasing yields nearly 5 bu/A.
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