Tag Archives: Urgent News

Wheat Disease Update – May 15, 2018

Three-day forecast for Fusarium head blight (FHB) risk on susceptible wheat varieties.

FHB risk is increasing in Virginia and will continue to increase over the next several days. Risk is highest on the Eastern Shore, but susceptible varieties such as Shirley that are flowering over the next week will be at moderate to high risk in many portions of the state. Growers should monitor the FHB risk tool (www.wheatscab.psu.edu) as their wheat crop begins to flower. Consider applying a fungicide if risk is moderate to high, especially on susceptible or moderately susceptible varieties. Wheat that has completed flowering is no longer at risk. Fungicides should be applied at early flowering or up to one week later. Do not apply a strobilurin-containing fungicide since this can increase DON contamination. Recommended fungicides include Prosaro, Caramba, and Proline.

Steve Rideout, Extension Plant Pathologist at the Eastern Shore AREC, confirmed stripe rust on research plots of Shirley on Monday. FHB risk continues to be high on the Eastern Shore, so growers in this part of the state with varieties that are susceptible to stripe rust should consider an application of Prosaro, Caramba, or Proline since these will control both FHB and rust.

Stripe rust on wheat.

For assistance with disease identification or management recommendations, contact Dr. Hillary L. Mehl, Extension Plant Pathologist (hlmehl@vt.edu).

 

Potato Late Blight in North Carolina

The following advisory is posted on behalf of Dr. Steve Rideout:

Late blight was found on potato in Camden and Pasquotank counties in North Carolina over the weekend. We will be processing the samples to determine more information on race/fungicide sensitivity. In the meantime, growers are encouraged to scout their tomato and potato fields for the disease.  Preventative fungicide applications are recommended, particularly near the outbreak area in NC.

If you have questions please let us know.  You can access current recommended materials for late blight in the commercial and homeowner vegetable production guides.  Also, you can visit the following web page for more information on this disease:

https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/ANR/ANR-6/ANR-6_pdf.pdf

This is a serious threat to potato and tomato production in the Commonwealth.  Please let us know if we can help.

Wheat Disease Update – May 2, 2017

Following last week’s rain, the risk for Fusarium head blight (FHB or scab) infections has increased, and the risk is very high even for moderately resistant varieties in certain portions of the state (see FHB Risk Map). Much of the wheat crop is beyond the early flowering stage, but for fields where wheat is currently flowering a fungicide may be needed to protect the crop from FHB infection and DON contamination. Recommended fungicides include Caramba, Prosaro, and Proline. Fungicides are most effective when applied at the start of flowering and up to a week later. The greatest coverage of the heads can be achieved by applying fungicides in 5 gal/A by air and 15 gal/A by ground with a 300-350 um droplet size and nozzles angled forward at least 30 degrees.

FHB risk on May 2, 2017 for moderately resistant wheat varieties. Susceptible wheat varieties that are currently flowering are at high risk for FHB infection throughout Virginia.

Stripe Rust Confirmed in Wheat on the Eastern Shore of Virginia

On Friday, stripe rust was confirmed on a wheat sample from a field in Northampton County, Virginia. Steve Rideout, Extension Plant Pathologist at the Eastern Shore AREC, reported that infection is fairly severe and rainy conditions will favor the pathogen’s development.  This is an early sighting for this disease and constitutes a serious threat to our wheat crop. The disease was found on Shirley, which based on observations in previous years in known to be highly susceptible to stripe rut. A previous post with management recommendations including variety susceptibility ratings and a fungicide efficacy table for stripe rust and other wheat diseases can be found here:

http://blogs.ext.vt.edu/ag-pest-advisory/stripe-rust-found-in-north-carolina-wheat/

You should be scouting your wheat crop at this time, and if stripe rust is found on a susceptible variety, a fungicide application is recommended. If you have any questions or need assistance identifying diseases on your wheat crop, contact Dr. Hillary Mehl at the Tidewater AREC (hlmehl@vt.edu).

“Soil Management/Soil Fertility Seminars for Row Crops” meeting on March 16, 2017

We hope that you will be able to attend the meeting, “Soil Management/Soil Fertility Seminars for Row Crops” on March 16, 2017, from 9:00 AM – 12:00 PM at the Virginia Tech Tidewater AREC, 6321 Holland Rd, Suffolk, VA 23437. Here is the agenda:

9:00 AM – Introduction and Opening Comments, Dr. Hunter Frame

9:00 AM – 9:45 AM – Benefits of Conservation Tillage Systems/Introducing Cover Crops, Dr. Mark Reiter

9:45 AM – 10:30 AM – Nitrogen and Sulfur Management in Cotton Production, Dr. Hunter Frame

 10:30 AM – 10:35 AM – Break

10:35 AM – 11:05AM – Nitrogen Management in Corn and Winter Wheat Production, Dr. Mark Reiter

11:05 AM – 11:35 AM – Potassium Fertilization Requirement for Full Season and Double-Crop Soybeans, Dr. David Holshouser

11:35 AM – 12:00 PM – Potassium Nutrition of Cotton in Virginia: A look at Timing, Rate, and Source, Dr. Hunter Frame

LATE BLIGHT IN VIRGINIA

Late blight was found in Accomack County, VA yesterday on potato. Growers on the Eastern Shore and other areas of the Commonwealth should scout their fields and take preventative measures. Please let us know if you have any questions. For more information on this potentially devastating disease of potato and tomato visit: https://pubs.ext.vt.edu/ANR/ANR-6/ANR-6_pdf.pdf

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Wheat Disease Update – May 3, 2016

Due to the recent rain, scab risk is increasing in portions of Virginia, especially on the Eastern Shore and coastal areas. The scab risk assessment tool can be found at http://www.wheatscab.psu.edu. Many fields are at or near flowering. In most areas, moderately resistant (MR) varieties are in the low to medium scab risk category, but keep in mind that many acres are still planted to moderately susceptible (MS) or susceptible (S) varieties such as Shirley. In the eastern portions of the state, scab risk is projected to be high for susceptible varieties over the next week, and it will likely be necessary to work in fungicide applications between rain events. Fungicides targeting scab should be applied within 5-6 days of flowering (50% of main tillers starting to flower from the center of the head). Do NOT apply a strobilurin or fungicide pre-mix containing a strobilurin after flag leaf emergence (Feekes 9) since this can increase DON contamination in the grain. Prosaro, Caramba, and Proline are the most effective products for reducing scab and DON contamination. These fungicides will also control foliar diseases such as leaf blotch, stripe and leaf rust, and powdery mildew. Stripe rust has been observed on susceptible wheat cultivars in some fields for several weeks now, but levels remained low due to dry conditions. The recent rain and humid conditions have resulted in spread of the disease in some areas. Similar conditions are forecasted over the next week and the disease has the potential to spread rapidly, so growers should scout their fields immediately to determine if stripe rust is present.

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Wheat Disease Update – April 12, 2016

Stripe rust has been found on wheat in southeastern Virginia (Suffolk) and the Eastern Shore (Northampton County). Stripe rust is not observed every year, but it can be more aggressive than leaf rust and spread very quickly if temperatures are moderately warm and humidity/rainfall is high. Many wheat varieties are susceptible, and we do not have good stripe rust ratings for the region because the disease is fairly rare. Pictures showing typical symptoms of leaf rust and stripe rust are below. Fields should be scouted, and keep in mind it is more important to catch stripe rust early than leaf rust. If a field has good yield potential and stripe rust is present, a fungicide application is recommended. In addition to rust, powdery mildew has been reported from throughout Virginia and leaf blotch has been observed in southeastern Virginia, so as the wheat crop approaches the flag leaf emergence growth stage, it is time to start thinking about disease management. For specific fungicide recommendations, see my earlier post (April 7, 2016).

Stripe Rust

Leaf Rust

Leaf Rust