Fungicide spraying on soybeans is in full throttle. We’ve seen planes, helicopters, and tractors out spraying soybeans. Almost all soybeans planted before May 5th are at or near R3. We prefer to error on the early side with soybean applications, especially if we want to get an earlier start to harvest. If you use a higher rate of strob product, like 8oz of Aproach Prima instead of the 6.8oz for extended coverage, keep in mind, it will extend your coverage and make the beans stay greener longer this fall. (Good to catch late rains, not as good if you want to harvest early)
We’ve had quite a few questions the last couple days about white mold. With any disease outbreak we need all three parts of the puzzle for a disease to occur:
Host- all soybeans are susceptible, just at different tolerance rates than others
Disease- for a disease like white mold, do you have a history of it in the field? Spores can last 7 years and still come to the surface to release new spores if…
Environment – if the environment is favorable for development of this disease. For white mold we need high moisture and cool conditions (68-78). Last week’s rain and the cool, but damp mornings we’ve had could be favorable.
What can we do now? – Spraying a fungicide now could limit your damage. Infection occurs in the flowers and protecting the new ones will help. However, if the infection occurred before now (we’ve had flowers for about a month), the infection in the plant is already there, and you cannot undo it.
This is the same for SDS, Gray leaf spot, northern corn leaf blight, and all other diseases we see in a growing season. We need all three to be present for a disease to occur. We can protect the plant with a fungicide, but we won’t know if we should have spent the money on it until the end of the season.