Wednesday, April 25, 2012

Wheat Scouting Update and Disease Thresholds

A check of our research studies found that the wheat crop is at the Feekes 6 and 7 growth stages (first and second nodes) across the state. This is an important time to be out in the wheat and scouting to determine if the use of a foliar fungicide will be needed as we move into flag leaf emergence (Feekes 8). The flag leaf is the most important leaf, accounting for upwards of 50% or more of the final yield and a goal with the use of a foliar fungicide is to protect this leaf. Most of the questions to date have been about powdery mildew. Susceptible varieties are showing significant disease pressure as warm March temperatures contributed to lush vegetative growth and in some cases pre-jointing lodging.

Looking ahead, there exist some thresholds as you scout at Feekes 7 and 8 to determine if a foliar fungicide may be warranted.

At Feekes 7, the thresholds are:

Powdery mildew: check the uppermost leaf - the threshold is an average of five pustules per leaf.

Wheat leaf rust: check any leaf - the threshold is an average of one pustule per leaf.

Septoria leaf blotch: check the uppermost leaf - the threshold is 25% of the leaves having expanding blotches

At Feekes 8, the thresholds are:

Powdery mildew: check from the flag-2 leaf (2nd leaf below the flag leaf) and upward - the threshold is an average of five pustules per leaf on the flag-2 leaf.

Wheat leaf rust: check from the flag-3 (3rd leaf below the flag leaf) and upward - the threshold is an average of one pustule per leaf on the flag-3 leaf.

Septoria leaf blotch: check from the flag-2 and upward - the threshold is 25% of the leaves having blotches

If you note disease in the lower canopy but not on any of the leaves discussed above, consider increasing the frequency of your scouting to determine if there is evidence of new pustules or blotches moving into the upper canopy.

For further information regarding factors to consider for determining the need for a foliar fungicide recommendation, please check here.

For information regarding the efficacy of several foliar fungicides against different wheat diseases, please check here.

Results across our different studies the past few years have indicated that the best response to a foliar fungicide application has occurred when powdery mildew was the target and the wheat variety was susceptible. When the wheat variety was resistant to powdery mildew, we have not seen a consistent response, if at all.

Tuesday, April 10, 2012

Updated Wheat Fungicide Table

With wheat growth and development ahead of normal in 2012, it is important to pay attention to the growth stage when determining if there is a need for the use of foliar fungicides. Active scouting is important to determine which diseases are present and either the incidence and/or severity of each disease relative to wheat growth stage. To help in understanding the efficacy of different fungicide active ingredients, the NCERA-184 (Management of Small Grain Diseases) committee reviews and updates the Fungicide Efficacy Table for Control of Wheat Diseases each year. Ratings for different active ingredients are provided and range from poor to excellent for the following wheat diseases: powdery mildew, Septoria leaf blotch, Stagonospora leaf/glume blotch, tan spot, stripe rust, leaf rust, stem rust, and head scab. These ratings are based on results and observations from trials conducted across different locations (i.e., states) and years and is meant only as a guide. It is important to read and follow the label carefully regarding application timing and recommended rates against different diseases.

Tuesday, April 3, 2012

Access a Wealth of Crop Management Info Courtesy of the Soybean Checkoff


As part of its tech transfer efforts, the United Soybean Board purchased 500 one-year subscriptions to the Plant Management Network (PMN) for soybean growers and the consultants who work for them. These subscriptions are available on a first-come, first-serve basis, and they are intended for individuals who did not subscribe during USB's 500-subscription promotion last fall.

This subscription includes access to PMN's entire collection of “Focus on Soybeans” webcasts. More than 50 soybean webcasts have been produced to date, and they feature actionable crop management information from experts who work in the field. PMN subscriptions also include access to nearly 8,000 fungicide, nematicide, insecticide, and biological control trials; more than 1,000 applied crop management research articles; nearly 3,000 crop management news articles; about 5,000 images; tens of thousands of extension documents, and other information useful for growers and consultants. All this information is located through in one central website and searchable by keyword.

You can sign up for a free one-year subscription to all the Plant Management Network's content through the signup form at the following short link:

Just enter the required contact information, scroll down toward the bottom of the page, enter your preferred username and password, and click “submit”. Make sure to record your username and password on paper for safekeeping.

Once you subscribe, you'll get article alerts once a month in the form of PMN's Update newsletter. Click through to whatever content you like. If it's subscriber-only content, you'll be prompted to fill in your username and password.

Here's a listing of PMN's soybean-inclusive resources, all of which can be accessed through Focus on Soybean

There are only 500 subscriptions, and they went quick the last time this was done. So please fill out the signup form as soon as possible!