Recent mild temperatures and the mild winter are setting the stage for rapid development of marestail/horseweed (Conyza canadensis) this spring. Marestail was particularly troublesome last year in soybeans. Marestail can germinate in both the fall and the spring. It is more likely to overwinter in the rosette stage during mild winters. If you wait until your typical burndown the marestail may start bolting and therefore be more difficult to control. Adding to this difficulty, many marestail populations are resistant to Roundup (and other glyphosate containing products). You should scout your fields targeted for soybeans now to identify overwintering marestail. Marestail control can be achieved with 2,4-D or dicamba now and still offer plenty of time to avoid plant back restrictions (up to 15 days for 2,4-D or up to 28 days for dicamba). Glyphosate resistant weeds and the difficulty in controlling more mature weeds underscore the need to scout fields earlier and use some alternative herbicides in your program. Always consult the product label for specific instructions.
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
There may be more peanut and cotton acreage planted in the V-C region this year than in 2016; and growers may wonder what crop to start planting first and which one last. These are legitimate concerns and we may have, at least in part, answers.
For peanut, mid-May planting seems to carry least risk compared with late April to early May or late May to early June plantings. This is quite common knowledge gathered through extensive research at the Tidewater Agricultural Research and Extension Center in Suffolk VA and Peanut Belt Research Station in Lewiston NC. However, researchers agree that all depends on the weather. For example, research I did in 2009, a relatively cool and wet year with 17 inches of rainfall from May through the end of August, clearly showed that April 20 planting resulted in a statistically significant yield reduction of 780 pounds per acre in comparison with a May 15 planting. At the state level, average yield in Virginia in 2009 was 3700 pounds per acre, similar with the average yield in 2016. Year 2010 was hot and dry with less than an inch precipitation in June, July and August combined. In this year, state average yield was only 1800 pounds per acre and our results indicated that April 15 planting of Bailey resulted in substantially more yield than late May (May 21) planting. The majority of other peanut commercial cultivars tested in that year responded in a similar way; but there were a few exceptions like Sugg, Gregory, and the runner Georgia 09B, which performed well when planted on May 3, but still low when plated on May 21. The first two weeks in May (maybe end of April too with good thrips control) may be best for peanut planting if April and May are warm with constant daily temperatures of 65 °F or more, sunny days, and night temperatures of 45 °F or more, and soil has “right” moisture; if moisture is excessive, the soil is probably cool. If April and May are cool and wet like last year, maybe waiting for after mid-May to plant peanut is the best option. Varieties seem to respond differently to planting time, but information on the new high oleic cultivars needs investigation.
In 2011 and 2012, I looked at how combination of planting date, seeding rate and tillage affects peanut yield. Results from these years were also dependent upon the specific weather conditions of each year. Across the state, both years were “good” years for peanut, with state averages of 4100 and 4200 pounds per acre; but in 2011, the hurricane in August dropped 18 inches of water at one time, and weather was considerably warmer than in 2012. In 2011, planting on April 25, May 5 or May 23 did not significantly changed yield, in particular when 5 or 6 seeds per foot-row were seeded. Some yield reductions were observed when only 3 seeds per foot were used. However, in 2012 Bailey yielded approximately 1000 pounds per acre more when planted on May 12 in comparison with April 30 and May 23 or June 1; and yields were about 100 pounds per acre greater in conventional versus strip till.
We concluded that the optimum time for peanut planting in Virginia is May 5 to May 20. Planting early may have lower yields due to thrips damage, and cool and wet soils; later plantings may also drop yield due to poor germination and crop stand; and recommended increase of seeding rate to 5 or 6 seeds per foot when planting outside this time window. More information on this research is here.
A Mid-Atlantic Soybean Disease Scouting Guide was recently developed by Extension Plant Pathologists from Virginia Tech and the University of Delaware in cooperation with the state Soybean Boards and the Soybean Checkoff. An online version of the guide can be found here:
Hard copies of the guide are available at the Virginia Tech Tidewater AREC, and requests for guides can be sent to Dr. Hillary Mehl (firstname.lastname@example.org). These will also be available at grower meetings and field days in 2017.
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).
Research at the North Carolina State University showed that peanut yields were lower when planted on fine-textured soiled in strip tillage in comparison with conventional tillage. Yield reduction appeared to be associated with greater pod loss in the digging process for the strip versus conventional tillage. Use of stale seedbeds, by bedding rows without other tillage operations sometime after the harvest of previous crop and 4 to 6 weeks prior to planting peanut, was further proposed as a tillage practice that could alleviate yield reduction due to strip tillage. Research using corn, cotton and grain sorghum as rotation crops showed that, indeed, depending on year and location peanut yielded greater in stale seedbed and strip tilled land versus just strip-tilled soil. For example, in 2006 at Rocky Mount, NC, when soil was bedded and strip tilled, pod yield was 3620 pounds per acre, significantly more than 2570 pounds per acre when peanut was planted directly into stripped soil and crop stubble. However, similar responses were not observed in 2002 at either Lewiston or Rocky Mount; which probably denotes that more research is needed to document if stale beds in crop stubbles and in strip tillage peanut production work. According with these researchers, peanut yield in longer rotations was higher than yield of shorter rotation, but the rotation crop had no effect. The full article is here peanut-notes-2017-no-23-peanut-strip-tilled-into-grain-sorghum-stubble.
The EPA is in the process of reviewing some of our older, broad-spectrum classes of insecticides. The comment period is now open for the preliminary ecological risk assessment of pyrethroids. I strongly support the need for continued availability of these materials because they are relatively safe for mammals and biodegradable. Importantly, pyrethroids are the only option for pest control of certain insect pests in some cropping systems. Entomologists, including myself, at universities throughout the Southeast have expressed their support for pyrethroids in a letter to the EPA. However, the EPA is really looking to hear from people that use these products responsibly. The below link provides a tool to make comments on EPA dockets without looking up each product individually. It also includes the type of information that is most helpful and a template to follow if so desired. Comments from our Virginia growers will be much appreciated!
The following is being issued on behalf of Roy Flanagan, Virginia Cooperative Extension ANR Agent, Virginia Beach (meeting information and registration forms can be found on my January 30, 2017 blog). This is a reminder for folks to register if you plan to attend any of the 2017 Mid-Atlantic Strawberry Programs in Virginia Beach. The room block with Fairfield Inns and Suites filled up quickly, we have increased that group of blocked rooms at the special rate of $86 per night. If you tried to register and had issues, please email Roy Flanagan directly and he will get you in touch with the right person to get your room issues taken care of and get the reduced rate.
If you have questions, please contact Roy Flanagan.
Agriculture Extension Agent/ Virginia Beach
Office: 757-385-GROW (4769)
The European Union (EU) is reviewing the current maximum residue levels (MRLs) for pesticides, some being used in peanut production. The process started in 2016 and will continue in 2017. As expected, peanut imports in EU may be affected by these changes. I am providing here information on these products (credit David Jordan and American Peanut Council), and I will continue to do so when I have new information. Although under review, please note that not all pesticides may have their MRLs lowered. peanut-notes-2017-no-12-comments-on-pesticides-eu-peanut-imports peanut-notes-2017-no-11-wto-communication-on-pesticides-and-mrls
The following information is posted on behalf of Roy Flanagan, Virginia Cooperative Extension ANR Agent, Virginia Beach. The first attachment (a Word document) includes details on the Mid-Atlantic Strawberry Programs (Feb. 27-Mar. 1, 2017), and the second (a pdf file) is the registration form.