Year after year, I’ve found that the farmers who achieve the highest wheat yields and profits are the ones who nail input timing. Growing up on a family farm on the eastern coast of England, I learned the importance of timing early on. My grandfather often said that the difference between a good farmer and a bad farmer is a week.
Close inspection of the upper leaves reveals stripe rust is present.
Three decades later, timing—and a little luck—still makes all the difference, but now I think that window might be closer to three or four days, and even less in some instances.
To ensure accuracy, I encourage my clients to time applications based on crop growth stages and five- to 10-day weather forecasts. In most cases, they are able to hit the ideal application window for inputs, such as nitrogen.
By comparison, neighboring farmers who wait a couple of extra days might get rained out, delaying the fertilizer application by as much as a week. I have seen numerous examples where fields that were given a timely nitrogen application followed by a rain to wash the nutrient into the soil performed much better than surrounding fields that missed the application window and the rain.
It’s all in the timing. The sprayer capacity necessary to achieve adequate application timing depends on a number of factors, including the average number of spraying days per month during each stage of the crop development and how much yield loss will result from the application being delayed.
Most wheat producers should strive to make each pass across all their wheat acres within a five- to sevenday window. If you can’t achieve this goal, you probably don’t have sufficient sprayer capacity. In many cases, a larger capacity sprayer or an additional tanker to tender liquid to the sprayer is probably justified. I have seen lots of examples throughout the years where producers were resistant to upgrade their sprayer capacity, but the yield losses caused by delayed applications has cost them more than they would have paid for the upgrade.
Cereal fungicides are generally the most susceptible to poor timing, especially within a heavy disease pressure environment. In most cases, the difference between a well-timed fungicide application and one made two to three days late can be as much as a 10 bu. to 20 bu. per acre yield loss. Stripe rust is a good example. It’s a disease that can spread quickly within the crop canopy when favorable weather conditions are present.
One of the biggest challenges with cereal diseases in general is understanding the latent period. This is the time that elapses between initial disease infection and visual symptom s appearing on the leaf surface. At 60°F to 70°F, the latent period for stripe rust is 10 to 12 days. When stripe rust symptoms start to appear, you’re already 10 to 12 days late with your fungicide, especially if you apply a fungicide from the strobilurin family, which are excellent products but offer only protective activity.
Mail questions to Phil Needham, Farm Journal, P.O. Box 958, Mexico, MO 65265 or e-mail firstname.lastname@example.org. Questions will be answered on this page. Individual replies are not possible. The information provided here is not considered a replacement for personalized agronomic consulting.