Maintain yield potential by reducing stress – AgriNews

Bloomington, Illinois — Whether to apply fungicides is an annual decision in crop production — and the majority of farmers choose not to.

“Although the effectiveness of fungicides is certainly proven, there is a long way to go to adopt fungicides as a tool for soybeans in Illinois and across the country. 2021 Illinois Soybeans, Bayer Crop Science and Technology Development Representative. Jason Kerr, the association’s CCA soybean envoy, is a recent ILSoyAdvisor webinar, with many possibilities as about three-quarters of soybean fields have not been sprayed with fungicides at this time.

“Many of the most popular varieties, hybrids and cultivars have the highest yield potential and respond dramatically to the application of fungicides. By reducing stress, those plants have a potential harvest. You can maintain the amount. “

The move towards reducing tillage also makes the decision to apply fungicides important.

“As we move to an increasingly minimal no-tillage system, we will leave more crop residues and more inoculum for disease outbreaks, so it will be repeated. However, we aim to use fungicides as a tool to manage these problems. As seeds and other inputs become more expensive and commodity prices rise, spraying fungicides is even more valuable. It will be something, “says Kerr.

As with weed management and herbicide resistance, multiple behavioral patterns are an important part of disease management. Multiple modes are used to combine the strength of the fungicide to increase performance by increasing consistency across weather conditions.

“Especially in high-priced environments, we actually leave money on the table and yields on the table by not using germicides.”

— — Jason Carr, Bayer Crop Science and Technology Development Officer

Kerr recommended attacking the fungus in multiple ways with both prophylactic and therapeutic fungicides.

The fungicide classes and behaviors are as follows:

Inhibitor / quinone outside strobilurin — Great for prophylactic use. Stops the development of spores. Soybeans treated with strobilurin fungicides often tolerate water stress well and promote increased yields in the absence of illness.

Demethylation inhibitor / triazole — Prevents, heals and protects plants. When a plant becomes infected, it can prevent the infection from getting worse. Most of the increased yields are related to disease control and not due to the physiological response of the plant.

Succinate dehydrogenase inhibitor — Prevention with several treatments; stop the fungus from breathing.

Application checklist

Carr has provided the following checklist to help you determine if you need to spray a fungicide.

• Frequent rainfall, dew, humidity — the leaf surface is dry for more than 10 hours.

• Crop rotation — corn and corn, soybeans and soybeans.

• No-till or no-till cultivation.

• Late planting date — more important for corn.

• Hybrids of disease-prone varieties.

• Stressed fields — hail, dryness, etc.

• Early evidence of illness in the field.

• Medical history or outdoor accommodation problems.

• Seeds or grains sold for the premium market.

• The more criteria that are met, the more likely you are to see an increase in yield.


“In general, soybeans need to be sprayed from R2 to R4. I really want to target R3, but timing is not so important. It’s better to do it in that common time frame. It’s important. There is a fairly wide window to get a yield response, “Kerr explained.

“There are exceptions to certain diseases, such as mildew. Mildew infects plants through flowers and must be applied with a fungicide when soybeans begin to bloom. Mildew with R1 and R3 fungicides Is best controlled. There are other examples of illnesses where timing may be a little more important.

“A common rule of thumb for application time zones is whether to increase the effectiveness of the fungicide at higher humidity. It does not evaporate so quickly, stays on the leaves and is more likely to translocate to the leaves. I have a lot of time. Spraying during the day can cause the fungicide to evaporate rapidly, especially on dry days when the humidity is not very high, reducing its effectiveness in invading the plants. “

Studies have shown similar reactions to air and ground use, according to Kerr.

“The application method is not so important. If you want to see the benefits, it is more important to apply the application to the crop,” he added.

Field trial

In a 2020 field study using 85 datasets, 93% of growers “confirmed win rates and 82% confirmed the economic benefits of spraying fungicides (2 or more bushels),” Carr said. Mr. says. The average yield benefit in all trials was 4.8 bushels per acre.

Other findings from the exam are:

• Soybean yield response to fungicides and varying populations. The larger the population, the greater the incidence of illness. However, there is a consistent yield response to fungicide treatment throughout the population. Better responses are often seen in lower populations. Approximately 120,000 seed populations, including fungicides, produce the highest return on investment.

• Fungicide treatment does not seem to affect maturity. The stems will remain green with a slight delay, which can delay harvesting, but are often the highest yielding varieties. After that, soybeans increased in water at the time of harvest. Maintain yield potential by reducing stress – AgriNews

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