Field Crops

Early Season Wheat Diseases and Fungicides

By: Dr. Pierce Paul, OSU Extension

The wheat crop in Ohio is now between early boot (Feekes 10, in the south) and approaching Feekes 8 (flag leaf emergence) in northern counties. Cooler-than-usual conditions over the last few weeks have slowed the crop down considerably, but as temperatures increase, the crop will advance through several growth stages over a relatively short period. Cool conditions have also kept foliar diseases in check, but Septoria, and to a lesser extent, powdery mildew are still showing up in some fields. Septoria tritici leaf spot is favored by cool, wet conditions similar to those experienced over the last several weeks. It usually shows up first on the lower leaves as yellowish flecks that later develop into irregularly-shaped, brownish-gray lesions, with easily-seen dark-brown to black spots (called pycnidia) in the center. Cool temperatures and high relative humidity are also required for the development of powdery mildew. Typical symptoms of powdery mildew are whitish fungal growth (pustules) on the surface of leaves and stems. If the variety is susceptible and conditions continue to be favorable, a fungicide application may be warranted to prevent both diseases from reaching the flag leaf before grain-fill.

Septoria tritici leaf spot on wheat – note the black dots (pycnidia) inside the lesion.

Most of the fungicides commonly used on wheat are rated as very good or excellent against Septoria and good or very good against powdery mildew. See the attached chart for fungicide options and efficacy. Remember,

Powdery mildew on wheat leaf – as the name suggests, note the powdery, white pustules.

always read and follow the labels when making an application. For both diseases, a single application between Feekes 8 and Feekes 10 would be sufficient to protect the flag leaf and minimize yield loss. However, applications made at these early growth stages will not provide adequate control of late-season diseases like head scab and Stagonospora glume blotch. So, you should scout fields before making your fungicide application decisions. If powder mildew and Septoria levels are low as the crop approaches heading (Feekes 10.5), you may be better off waiting to treat fields at anthesis (Feekes), as this will help to suppress head scab, which is still the most damaging and important disease of wheat in Ohio, while at the same time provide very good control of Septoria, powdery mildew, and late-season diseases such as Stagonospora and rust.

 

 

Why Should You Calibrate Your Sprayer Even If it has a Rate Controller?

by: Erdal Ozkan, OSU

Whenever I give a presentation about the need to calibrate a sprayer and how to do it, there is always someone asking me this same question: “I have a rate controller in the cab that regulates the flow rate of the sprayer regardless of the changes in sprayer ground speed. I just enter the gallons per acre application rate, and the controller does the rest, just like a cruise control in a car. So, should I still calibrate the sprayer? The answer is, Yes, a calibration should be done. Although the rate controllers do an excellent job with regulating the flow rate of nozzles to keep the application rate constant regardless of the changes in travel speed, a manual calibration at least once a year is needed for two reasons: 1) to ensure the rate controller is functioning properly, 2) the rate controller is not forced to operate outside the pressure operating range for the nozzles on the sprayer boom. Let me elaborate on both points I made and share with you the reasons why a manual calibration of a sprayer is a good idea. Continue reading →

Wheat Growth Stages

OK, Mother Nature is not cooperating which means we can’t talk about corn and bean planting so let’s talk about the crop we do have growing – Wheat

Source: K-State University

Knowing what growth stage your wheat crop is at is essential for nitrogen, herbicide and possibly fungicide applications.  Most of the wheat I have seen in the county so far is between Feekes 5 and Feekes 6.

Feekes 5 is the time to be making your last nitrogen applications and applying herbicides as needed for weed control.  However at Feekes 6 you should cutoff for nitrogen applications to avoid leaf injury.  Additionally some growth regulator herbicides, like 2, 4-D and dicamba should not be applied.

Alternative spring burndown/postemergence strategies when herbicides are in short supply

by: Dr Mark Loux, OSU

There is a lot of speculation about herbicide shortages for the 2022 growing season, and some products are apparently getting more expensive and/or scarce now. This will affect herbicide buying and weed management decisions for the 2022 season. The two main active ingredients that we’re hearing about right now are glyphosate (Roundup, others) and glufosinate (Liberty, others), for which prices have increased substantially. There will likely be limited supplies of other pesticide active ingredients as well, but in the short term, a shortage of these two active ingredients poses some major challenges for corn and soybean production. The purpose of this article is to discuss ways to minimize the impact of herbicide shortages, primarily glyphosate, on corn and soybean production. As you search for alternatives to these two herbicides and others, the weed control guides and technical guides produced by University Extension and industry are an important tool for planning weed management programs and herbicide purchases.

Some guiding principles based on our experience that may help with decisions, especially where glyphosate will not be in all applications:

  1. Spring tillage is an option to replace herbicide burndown. Can cause long-term compaction problems if tilled when too wet. Waiting until weeds are large makes tillage less effective. Weeds that survive tillage will be difficult to control with POST herbicides. In other words, till when soil conditions are fit and before weeds are huge.
  1. Where it’s only possible to use glyphosate once, it may be needed most in the burndown. Saflufenacil can be added for enhanced control of rye and ryegrass, and marestail. ACCase herbicides (e.g. clethodim, quizalifop) can then be used for POST grass control in soybeans. Glufosinate, Enlist Duo, or XtendiMax/Engenia can be used for many broadleaf weeds, especially the glyphosate-resistant ones. Where residual herbicides are omitted, or do not provide enough control, we would expect POST treatments to struggle more in the absence of glyphosate with weeds such as lambsquarters. So use residuals. Glyphosate is still more than just a grass herbicide.

Continue reading →

Central Ohio Agronomy School – Night #2

David Marrison, Coshocton County ANR Educator shares insights and options on retirement planning for you and your farm.

Night 3 Speakers – Monday March 21

Corn Disease Update

Dr. Pierce Paul, OSU Plant Pathology
Tar Spot – Do we have it, Can we control it? Aerial Applications of Fungicides … is 2 gallons really enough? Vomitoxin Research Results.

Carbon Credits – Is There Really A Market In Ohio?

Mike Estadt, ANR Educator Pickaway County
What is a carbon credit? What is a carbon credit worth? What do I have to do? Mike will answer these and many other questions about selling carbon credits.

Central Ohio Agronomy School – Night 2

John Linder, Chairman National Corn Growers Association and Tadd Nicholson, Executive Director Ohio Corn & Wheat share their insights on the “Big Picture” of Agriculture at night #2 of the Central Ohio Agronomy School.

Night 3 Speakers – Monday March 21

Corn Disease Update – Dr. Pierce Paul, OSU Plant Pathology
Tar Spot – Do we have it, Can we control it? Aerial Applications of Fungicides … is 2 gallons really enough? Vomitoxin Research Results.

Carbon Credits – Is There Really A Market In Ohio? – Mike Estadt, ANR Educator Pickaway County
What is a carbon credit? What is a carbon credit worth? What do I have to do? Mike will answer these and many other questions about selling carbon credits.