This week, stripe rust was found in Robeson County, NC. The disease was observed in wheat variety SS 8404 which is susceptible to stripe rust. Current weather conditions (cool, wet) are generally favorable for spread and development of stripe rust, and it will likely move north into Virginia before the end of the wheat growing season. However, stripe rust is typically a problem only in susceptible varieties. With this in mind, it is important for growers to determine which of their planted varieties are susceptible to stripe rust so they will be prepared to scout and apply a fungicide once the disease makes its way to Virginia. One popular variety, Shirley, is very susceptible to stripe rust, and outbreaks of this disease were observed in some fields planted to Shirley in 2016. Stripe rust and other disease ratings for wheat in Virginia can be found in the link below for the VCE Publication Small Grains in 2016. A link to the Diseases in Small Grains chapter from the 2017 Pest Management Guide for Field Crops is also attached. This includes management recommendations and a fungicide efficacy table for stripe rusts and other diseases of wheat. Several different fungicides are available that are rated “Excellent” for stripe rust control, but fungicides are most effective when applied prior to disease development. Thus, if you know you have a variety is that is susceptible to stripe rust you should be scouting those fields and apply a fungicide if stripe rust is observed. There is no need to spray wheat for stripe rust at this time, but it is important to be aware and be prepared. If you suspect you have stripe rust, you can send a photo and/or sample to Dr. Hillary Mehl at the Tidewater AREC (email@example.com).
Small Grains in 2016 (variety disease susceptibility ratings)
PMG2017: Small Grains Disease
We look forward to seeing you January 25th and 26th at the 27th Annual Eastern Shore Ag conference & Trade Show! You can find the program online at: https://onedrive.live.com/?authkey=%21AEczhxLIHkUCwmY&cid=05F6B732110DB231&id=5F6B732110DB231%2129963&parId=5F6B732110DB231%21813&o=OneUp. Virginia pesticide re-certification and Certified Crop Adviser credits will be available. See the program for more information.
The event will be held at the Eastern Shore Community College Workforce Development Center, 29300 Lankford Highway, Melfa, VA 23410. When you enter the driveway to the Community College, we will be meeting in the building to the left.
The Annual Oyster Roast will be held on Wednesday night, January 25th beginning with a social at 6:00 pm and oysters served at 6:30 pm. Along with oysters, there will be all-you-can-eat barbecue, sides and beverages. Tickets will be $35.00 in advance and $40.00 if purchased the day of the oyster roast.
If you have any questions or concerns please contact either Theresa Pittman (firstname.lastname@example.org) or Ursula Deitch (email@example.com) for accommodation. Thank you!
Join us in Melfa, VA for the 27th Annual Eastern Shore Agricultural Conference and Trade Show on January 25-26, 2017. This event is free, open to the public, and will be held at the Eastern Shore Community College Workforce Development Center. We will offer Virginia Pesticide Recertification credits for categories 1A, 10, 60, and 90. We will also offer Certified Crop Adviser Credits for nutrient management (2), soil and water (1), integrated pest management (4.5), crop management (6), and professional development (0.5). Click on the following link for topic areas being presented: ag-conf-press-release-2017
November 15-17, 2016
Princess Royale Hotel in Ocean City, MD
Registration is open for the 22nd annual Mid-Atlantic Crop Management School. This year’s school will feature 2 ½ days of timely presentations in the areas of crop management, nutrient management, pest management, soil and water management, and climate. This year, the school will also feature the popular Crop School on Wheels field tour (limited to 50 participants). Nutrient management (VA, MD, DE, PA), pesticide, and certified crop adviser (CCA) credits will be available. Register early for the best selection of sessions.
The session schedule is online at: https://cdn.extension.udel.edu/wp-content/uploads/sites/12/2016/09/23151701/2016_CMS_Program_Final.pdf
Registration information is posted at: http://www.cvent.com/events/2016-crop-management-school/event-summary-bbd4a7d2717545af9770626ef761a930.aspx?tw=E3-C1-0B-14-32-A0-CB-AB-1C-D6-9A-06-46-74-20-5F.
Contact Amy Shober (firstname.lastname@example.org) or Jarrod Miller (email@example.com) with questions about the school. We look forward to seeing you there.
The Mid-Atlantic Crop Management School is organized by Extension Specialists from Virginia, West Virginia, Delaware, and Maryland featuring speakers from across the nation.
Initial results from the 2016 Virginia state wheat and barley tests are available in excel format at:
The full document and summary is coming soon.
It’s been many years since we’ve seen a true armyworm (see the attached image) infestation in our small grain crop, but one is reported to be ongoing in the barley and wheat fields on the Eastern Shore. These caterpillars can do two types of damage—leaf feeding and head cutting. Leaf feeding is rarely extensive enough to warrant control, especially if fields are within a couple of weeks of harvest. Head cutting is less tolerable. For some reason no one has been able to explain, caterpillars will sometimes eat through the stem below the heads casing them to drop to the ground. Finding otherwise healthy looking heads-short stems on the ground is a good indicator that true armyworms are present and still active. It is often hard to find them on plants during the day as they typically feed more at night and seek cover under plant residue during the day. When we have worked with this pest, we found that fields with the most plant residue on the soil surface tended to have the heaviest infestations.
We do have thresholds for true armyworm for those motivated to scout for them. As a general rule, barley should be treated if the number of armyworms exceeds one per linear foot between rows and most of the worms are greater than 0.75-inch long. In wheat, armyworms tend to nibble on the tips of kernels rather than clip heads; thus, populations of two to three worms per linear foot between rows are required to justify control. In high management wheat fields with 4-inch rows, treatment is recommended when armyworm levels exceed 3 to 5 per square foot of surface area, or per linear foot of row.
If a treatment is warranted, there are a few good choices but the PHI (Pre Harvest Interval) may be a challenge. Some work we did many years ago showed that pyrethroids were generally effective but have a PHI of 14 days (example, Mustang Max) to 30 days (example, Baythroid), which could be a problem for barley, wheat not so much. Lannate has a PHI of 7 days but did only an OK job in our trial and not as good as the pyrethroids. We chalked that up to the fact that although Lannate has great efficacy against most caterpillar species, it has almost zero residual activity. So a day-time spray may not have had as much horsepower by the evening when caterpillars become active. Since our work was done, several new products have been introduced to the market that we have not tested, like Prevathon (PHI 14 days), and Besiege (PHI 30 days). These should work well. See the Pest Management Guide Field Crops 2016, 4-49, p. 53 for more product listings (http://www.pubs.ext.vt.edu/456/456-016/Section04-Insects-1.pdf).
With any treatment, coverage will be essential so deliver the highest volume you can live with and direct it to go as deep into the canopy as possible.
Italian ryegrass is one of the most troublesome weeds infesting small grain fields throughout Virginia. Currently, only Hoelon-resistant ryegrass has been confirmed in Virginia. However, many growers have complained the ALS-inhibitors (Osprey and PowerFlex) and Axial XL (ACCase-inhibitor) have failed to control ryegrass. To get a better handle on herbicide-resistant Italian ryegrass in Virginia, the VT weed team plans to screen ryegrass from across the state for herbicide resistance. Year 1 of the project will focus on the I95 corridor east. We will be traveling this area and collecting ryegrass seed for herbicide screening this fall. However, if you have had complaints of resistant ryegrass in your neck of the woods and are interested in screening it this year, we welcome your samples and will add them to our screen this fall.
If you are interested, see the sample information sheet below for sample, handling, and shipping information. For the sample, GPS coordinates are critical. If you have any questions, feel free to contact me.
HR Ryegrass Sample Info Sheet
“One year to seed; seven to weed”
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).
As the wheat crop approaches the flag leaf emergence growth stage, it is time to start thinking about disease management. When conditions are conducive to disease development (e.g. high humidity, warm temperatures) foliar fungicide applications may be necessary to protect wheat yield and quality. The mild winter in 2014/2015 resulted in early onset of foliar diseases in some areas, and powdery mildew and rust were reported from a few fields as early as December. Recently, powdery mildew has been reported from throughout Virginia, leaf blotch has been observed in southeastern Virginia, and leaf and stripe rust have been reported just south of Virginia in North Carolina.
Wheat Powdery Mildew
Once the flag leaf emerges, this leaf surface, which feeds the developing grain, should be protected from disease if symptoms are observed on the lower leaves and conditions are conducive to disease development. Fungicides containing a strobilurin should not be applied after heading but are a good option for control of foliar diseases as the flag leaf emerges. Late applications of strobilurins can increase DON (vomitoxin) if scab infections occur during flowering. Triazoles including Caramba, Proline, and Prosaro are good options for scab control and will also control late-season foliar disease. Currently, scab risk in the region is low but growers should consult the FHB prediction tool (http://www.wheatscab.psu.edu/) as the crop gets closer to flowering. Ideally, fungicide applications should be made based on scouting and/or risk of infection and disease development due to weather conditions. A fungicide efficacy table for many of the products registered for wheat can be found below.
2016 Wheat Fungicide Efficacy Table
As always, for more information on disease management in field crops feel free to contact Dr. Hillary Mehl, Extension Plant Pathologist by email (firstname.lastname@example.org) or phone (757-657-6450 ext. 423).