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.
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:
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 (firstname.lastname@example.org).
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 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
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.
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).
The Eastern Shore of Virginia Ag Conference & Trade Show is on! We are snow free, and looking forward to a great event on January 26 and 27, 2016. The event will take place at the Eastern Shore Community College Workforce Development Center in Melfa, VA. The full program can be found at: http://issuu.com/esarec/docs/flipbookfinal/1. We have been approved for Certified Crop Adviser (CCA) CEU credits (details at: https://www.dropbox.com/s/f34f3spg4quni7a/CCA_Credits_Handout_2016.pdf?dl=0), Virginia Nutrient Management Credit (1 credit), and Virginia Pesticide Recertification credits (information in the program). See you there! Directions can be found at: http://es.vccs.edu/about/mapdirections/.
Due to the frost and freeze advisories in effect from Sunday through Tuesday night (Oct 19 through Oct 21) in the V-C region, I recommend that peanut digging be stopped after today (Thu, Oct 15). Peanuts will need three days to dry in order to not be affected by frost. Resume digging only after temperatures become milder.
Frost advisory is available at http://webipm.ento.vt.edu/cgi-bin/listfrost
The Virginia Frost Advisory predicts that a frost is expected next Monday morning (10/19) for Suffolk, Capron, Waverly, Skippers, and Lewiston. A copy of the report can be downloaded below. For up-to-date frost advisories for the region, see the Peanut-Cotton Infonet (http://webipm.ento.vt.edu/cgi-bin/listfrost).
Another Virginia county has been found with sugarcane aphid in sorghum. Please see the attachment for more details. SCA_advisory_Sep_18_2015