Crops

Going Viral

Written by Jason Worthington on .

 When it comes to disease control in wheat, the focus is often on fungus. Fusarium head scab, leaf rust, stripe rust and even powdery mildew receive a lot of attention from growers and crop advisors as they inspect fields through the growing season. They select appropriate fungicides and time applications to optimize disease control.

However, viral diseases in wheat are just as important—and potentially just as harmful—but more commonly overlooked. This tendency stems in part from the fact that once viral infections are discovered in wheat nothing can be done to treat them. True, but there is plenty that can be done to prevent them.

Prevention methods, of course, depend on the particular virus you are facing. For example, soil-borne mosaic and spindle streak mosaic viruses can be averted, or at least limited, by selecting resistant varieties and avoiding planting wheat into poorly drained soils. The impact of wheat streak mosaic virus can be reduced by planting late or controlling nearby volunteer wheat and other grassy weeds. This limits exposure to wheat curl mites that transmit the disease.

Among all diseases, not just viruses, barley yellow dwarf is one of the most prevalent and damaging problems in wheat grown in MFA territory. Fortunately, with proper management barley yellow dwarf virus can be avoided.

Aphid species such as corn leaf aphid, greenbugs, English grain aphid and, most commonly, the bird oat cherry aphid can all transmit the barley yellow dwarf virus. Symptoms of this disease include stunted plants and yellow or red leaf tips. Depending on the amount of infection and vector populations, infected areas are generally found in patches that are 1-foot to 5-foot in diameter, with the worst symptoms near the center of the affected area. As the wheat matures, infected heads tend to be darker than their healthy counterparts. Grain from infected heads is often shriveled. Yield losses can be as high as 35 percent.

This past spring, visual signs of barley yellow dwarf virus were seen quite frequently throughout Missouri, more commonly in northern areas. While last year once again proved that all areas of the state are vulnerable, typically the potential for infection is worse in the south. Later freeze dates and milder winters allow for greater aphid activity in the fall. Though the disease can infect wheat plants at any point of their life cycle, fall and winter aphids cause infections that provide much more time for the disease to develop than a spring infection.

So why were infected fields more prevalent in the north this past year? There was no shortage of infected fields in any part of the state, and aphids were prevalent far into a mild winter. The difference appears to be seed treatments. Insecticide seed treatments were much more commonly used in the southern areas, where growers are more accustomed to growing wheat and managing for barley yellow dwarf control.

 Though there are some varieties with limited resistance and delayed planting can be helpful, effective control of aphid vectors is—by far—the most reliable way to prevent barley yellow dwarf virus. Scouting and foliar-applied insecticides can help control aphids, but even then some level of infection has likely occurred. Preferably, systemic insecticide seed treatments should be used to keep aphid populations from developing in the fall. Wheat fields with insecticide-treated seed showed an obvious advantage to fields planted with untreated seed.

It is also important to note that not all seed treatments are equal. The majority of available seed treatment packages offered for wheat do not contain an insecticide. Those that do often contain an insecticide rate that’s too low to be effective against aphids. However, products like MFA’s Crop Advantage Cereals Aphid blend ensure effective control with high use rates of the systemic insecticide, imidicloparid. Products that do not have these rates need additional imidicloparid if control of aphids and, in turn, barley yellow dwarf virus is desired.

While all potential challenges in the next growing season are easier to overcome with proactive planning, when it comes to barley yellow dwarf virus control, that foresight is not just beneficial but crucial. The old saying that “an ounce of prevention is worth a pound of cure” is surely an understatement in this case. If that ounce ensures the full rate of a seed treatment, then its worth is measured in bushels rather than pounds.

What we're learning from the dicamba dilemma

Written by Dr. Jason Weirich on .

As expected, the launch of XtendiMax and Engenia came with a few headaches. We have been preparing for the introduction of the dicamba- tolerant trait for the past few years. Since I joined MFA almost six years ago, we have had numerous employee trainings, producer meetings and special applicator sessions. For a while, I didn’t know if we would ever see this technology reach the farm gate with all the additional requests made by numerous government agencies.

Little did I know that my first complaint call on dicamba would come in early May. I also didn’t think the complaint would be failure to control 3- to 4-inch waterhemp. Looking at this technology in trials, we had decent control when timely applications were made. While the early-emerged waterhemp was a problem, I was overly impressed with what was happening with our giant ragweed and marestail. Quite often, I would get a picture and a text that said, “Look at what it can do!” I would respond, “Roundup used to, too.”

What I noticed to be different about the waterhemp that had emerged in late April and early May was that these plants had already put on a seed head. This is not typical of waterhemp for that time of year. However, we have new technology with new adjuvant requirements we were trying to figure out on the fly. We quickly noticed some of the issues and made a labeled change to meet the requirements for both XtendiMax and Engenia applications. We needed to do a better job on coverage and penetration of the target species. That’s why we included Xpond and Impetro II in all of our applications for better weed control.

Early on we had a lot of successes. We had producers and applicators calling in and telling me how well this product was staying put. I also had a producer tell me that I had been wrong about this technology being risky. He had applied the product right next to his house and garden with no issues. Mind you, we are talking about early applications. Here’s where it gets tricky. Maybe we got a little too comfortable with the technology. Maybe the success stories caused some of the applicators to relax in strictly following the requirements.

Then it happened. We got our first off-target complaint early June, and once it started, it didn’t stop. We had call after call after call. We obviously had our fair share of tank contamination, typical physical drift, wrong field, wrong tip, wrong pressure, wrong boom height, etc. We see these issues with other crop protection technologies as well. We also saw a fair amount of damage from our Group 15 herbicides such as Dual, Warrant and Outlook.

Then we saw damage that appeared to be “unexplainable.” In these cases, we had followed the label, tips, boom height, speed, weather, tank mix partners and so on, but still had movement. I wish I had the answer today to tell you what happened, but I don’t. I had several applicators look at me and say, “Doc, I followed the label, and it still moved.” I think it is safe to say that there is still a lot we don’t know about the dicamba molecule.

Overall, from our custom application standpoint, we did a better job than I thought we were going to do. I was expecting to see more mistakes than were actually made. We didn’t just put this in the hands of a new applicator; we put it in the hands of our veteran employees. Some of these applicators have been spraying for more than 30 years. They took the challenge and were successful, in my opinion.

As we move into the next growing season, we have to learn from what went right and what went wrong. We need to get out of our silos and join together to figure out how we can make this work effectively and safely for all of agriculture. I will write about dicamba a couple more times before next spring and will be on the speaking trail talking about the pros and cons that we saw this season.

Will crop rotation still protect against corn rootworm?

Written by Jason Worthington on .

 When discussing insect management with growers, the preferred strategy of management is often a “wait and see” approach. Waiting until insects are found before deciding on a management practice can be effective for some species, if a field is scouted thoroughly and frequently enough. However, this same practice falls woefully short on other species, especially when managing insects that could cause devastating yield losses or pose a predictable threat to a crop. Corn rootworm falls into both these categories.

The most damaging corn pest in North America, corn rootworm pressure is documented almost every year at some level in areas that are in a continuous corn rotation. Over the past two centuries, Missouri corn growers, unless they were in a corn-on-corn rotation, didn’t have to worry much about corn rootworm pressure. That may be about to change.

Crop rotation traditionally controls rootworm. That’s why there has been limited concern in our area about corn rootworm pressure. Beetle eggs would hatch in the spring, but if the larvae did not find a food source (corn), they would quickly perish. The vast majority of Missouri’s corn acres are in a corn/soybean rotation, so growers were putting an insect management plan in place with their crop rotations.

However, in July 2016, MFA Crop-Trak Consultant Kevin Moore discovered the likely presence of northern corn rootworm extended diapause, a longer life cycle in which the eggs remain dormant in the soil for two years or more before hatching. Evidence of larvae and adult beetles were found in numerous corn fields in a corn/soybean rotation in Atchison, Nodaway, Holt and Worth counties in Missouri as well as Page County, Iowa. Many other parts of the U.S. already experience extended diapause rootworm and cannot count on crop rotation for control any longer.

To confirm these findings, MFA partnered with the USDA to conduct lab testing of suspect beetle populations. In these tests, eggs from collected beetles endured a simulated winter. A typical diapause, or period before eggs hatch, is one winter. In an extended diapause, rootworm eggs must endure two or more winters before hatching. After the first winter and spring of testing populations collected from northwest Missouri, only 45 percent of the eggs hatched. While it is unknown what portion of the remaining 55 percent will hatch after a second winter, it is likely a significant number of these eggs are still viable and could threaten a corn crop. At 45-percent hatch after one winter, the numbers closely resemble testing of known extended diapause rootworm populations in South Dakota.

What does this mean for growers in these areas? First, the threat could be much greater in 2018 because it’s an even number year like 2016, when the extended diapause was discovered. Methods other than crop rotation must be used to control rootworm. The most effective plans must be proactively developed along with hybrid selection.

When it comes to managing rootworm, reactive control measures will not be effective. The two real options a grower has to control rootworm are Bt corn traits with multiple effective proteins such as SmartStax, and granular in-furrow soil insecticides such as Force or Aztec. Both of these control options require planning ahead. With few planters in the state set up for dry insecticide applications, traited seed will likely be the preferred method of control. The decision to purchase seed with rootworm control traits often happens before the prior year’s harvest is even complete.

While rootworm can be devastating to a crop and extended diapause situations may keep crop rotation from protecting us, we still have options to control this pest. Just like many of our most important decisions, we will have to plan ahead to ensure success against this emerging threat.

Clear Choice

Written by Allison Jenkins on .

 Statistics vary, but it can take hundreds to thousands of years to form an inch of topsoil—something that will never happen again in our lifetime or many generations to come. That’s why erosion control was a big factor in Davis’ decision to begin growing cover crops five years ago on his farm in Mexico, Mo.

When more than 9 inches of rain fell the last weekend of April this year, Davis realized just how well his cover crop of cereal ryegrass was working compared to fields without it.

“I had just planted a field of corn near my house, and at the end of the driveway the water flowing out of that field was just completely dirty,” Davis said. “The field of ryegrass next to it? The water running out of it was just as clear as can be. It didn’t have all that sediment and soil because the cover crop was holding it in.”

From an initial 20 acres of cover crops, Davis has now increased that number to around 200 acres out of the 1,200 he farms in total. The cover crops on his farm all precede soybeans.

“There’s no doubt cover crops are making a difference,” he added. “The soil I lose out of these fields, I’ll never get back. We have to do something to save it. I’d like to leave this farm better than what it was. Trying to do what’s good for the soil is one thing I can accomplish.”

He’s not alone in the quest to control erosion and reap other benefits of cover crops. An increasing number of growers across MFA country are embracing this practice in which normally fallow ground is planted between seasons. The cover crop is harvested, grazed or terminated in the spring before the cash crop is planted.

In Missouri alone, recent surveys indicate 600,000 to 700,000 acres of cover crops or possibly more, compared to 400,000 acres reported in the 2012 Census of Agriculture.

“We’ve seen a rapid adoption of cover crops in the area served by MFA, mainly due to erosion and water quality issues, and I think that trend will continue,” said Dr. Jason Weirich, MFA Incorporated director of agronomy. “We have a lot of rolling fields and steep hills in our geography, and we see erosion and ditches washed out every year. With cover crops, we’ve seen a reduction in soil loss. They’re very successful when used properly.” 

Though cover crops offer numerous other advantages, erosion control is also the top priority for Ben Anderson, who farms 1,000 acres near Boonville, Mo., with his father-in-law, Perk Hoecker. Anderson moved from Kansas to the farm with his wife, Julie, five years ago to help her father transition into retirement. The family’s hillside farm has been in continuous no-till for about 24 years, and cover crops have been an integral part of the operation for the last decade. All of their corn and soybeans now follow cover crops.

“For years, we saw a lot of our creeks running muddy, and we’d have huge washouts,” Anderson said. “This farm sits on rich glacial deposit dirt, and we got tired of seeing it go down the creek. We’ve been trying to keep that dirt here, and now our creeks are running clear. We get good water retention, too, which is huge for us in-season.”

“It’s not for everybody, but with rolling hills like ours, it’s a pretty sustainable practice,” added Anderson. “They aren’t making any more dirt, so we want to keep what’s here.”

With the loss of soil comes loss of nutrients, so controlling erosion also protects a grower’s fertilizer investment. “Any time we have water movement, yield potential is leaving that field along with the soil and nutrients,” Weirich said.

In Missouri and surrounding states, cereal rye is by far the most popular choice in cover crops, Weirich said. Both Davis and Anderson exclusively planted cereal rye this year. Other viable options for our region include triticale, wheat, radishes, turnips, oats, buckwheat, crimson clover or a mixture of several species. Italian ryegrass, however, is not recommended, Weirich warned.

“Italian ryegrass is in the Lolium family, which is the No. 1 species in the world for herbicide resistance,” he explained. “It makes a great cover crop, but it has too many risks. You don’t have any control options once it establishes and becomes resistant to herbicides.”

Along with erosion control, Davis said cover crops have helped with weed suppression and cooler soil temperatures in the heat of summer, and he expects to find improved soil health and organic matter when he samples his fields this fall. Plus, he’s seen a yield boost every year.

“Last year we planted into cover crops that were waist high,” he said. “All the beans did really good last year, and I thought there’s no way the cover crop beans could be that much better, but they were. Those beans were a good 4 to 5 bushels better than anything else we had.”

Yield increases were also reported by a majority of respondents in the 2016 Cover Crop Survey conducted by the USDA’s Sustainable Agriculture Research and Education Agency, Conservation Technology Information Center and the American Seed Trade Association. The fourth annual survey of 2,020 respondents, including a significant number from producers in MFA territory, showed modest yield gains in both corn (1.9 percent) and soybeans (2.8 percent) following the use of cover crops. Cereal rye was reported to boost soybean yields on a majority of farms, and 82 percent of those surveyed indicated that cereal rye also helped reduce weed problems—including troublesome herbicide-resistant weeds. 

Establishing cover crops can be accomplished in several ways—typically drilling after harvest or aerial seeding into a standing crop—depending on the timing of planting and type of seed, Weirich said. Termination timing in the spring is also critical, he added, to ensure the cover crop doesn’t hinder the progress of the cash crop to follow.

“I know a lot of guys follow their combine with a drill to plant cereal rye, and that works well,” he said. “If you want to have a tillage radish or turnip, you need to overseed that into the crop. The key is making sure you get good fall growth. The more fall growth you get, the better off you’ll be by the time you terminate the crop in the spring.”

Weirich said there’s no way to make blanket recommendations for cover crops because every situation is unique. He recommends the Midwest Cover Crop Council’s website. Available at http://mccc.msu.edu, the site features interactive tools that allow growers to make decisions at the county level based on the cash crop, planting and harvest date, drainage and goals.

“You have to make decisions based on your farm and what you want to accomplish,” Weirich said. “There are a lot of different options out there, so you need to know what you’re doing. It takes management the first several years. Don’t start with the whole farm. Figure out what works for you and your farm and then go from there.”

Nutrients now, flexibility later

Written by Kerri Lotven on .

 In the southern parts of MFA’s territory, producers like Billy Gourley of Gourley Land and Cattle in Ozark, Mo., are starting to think about the phosphorus and potassium levels in their fields. Split applications are popular here. By applying P and K in the fall and nitrogen in the spring, farmers in this area are able to spread out their resources, promote root growth in their pastures and ready their fields for the next season.

“When you fall fertilize,” Gourley said, “I believe you get more root growth, and your plant is healthier when it goes into dormancy through the winter. In the fall, you need that little bit of growth that comes with applying P and K because you can stockpile your grass and winter your cows without feeding as much hay.”

Gourley has about 2,000 acres of pasture enrolled in MFA’s Nutri-Track program and spreads P and K in the fall to winterize his pastures. He moved back to Ozark five years ago from Colorado to manage his family’s land. The pastures had been leased for the previous four years and needed a major overhaul. A few years ago, he attended a meeting where MFA personnel introduced grid-sampling.

“There were weeds everywhere, very little grass, no clover, no orchard grass,” Gourley said. “It was grazed to nothing. We came in with MFA and have done extensive amounts of renovation in our pastures. We’re not overgrazing. By grid-sampling and following proper soil-sampling and fertilizer programs, we’ve made leaps and bounds.”

Originally, Gourley wanted to hay his pastures. His plan was to fertilize in the spring, bale them once a year for hay, and then move in his cows to graze the rest of the time.

“When a bale is worth $22-25 and it costs $17-18 to put it up, the profit margin is not where it needs to be to make any money at haying,” he said. “I’m better off to buy my hay and graze my grass.”

In working with MFA, Gourley came up with another solution. He wanted to set up an intensive rotational grazing schedule that would give his cattle the ability to graze into early winter, allowing him to feed less hay. In the winter of 2015-16, Gourley supplemented grazing with more than 1,000 round bales, but in the winter of 2016-17, he was able to cut that number by more than half.

“Better management has just made our grass go further,” Gourley said. “We actually have over twice as many head now as we did in 2015 and 2016.” 

Splitting fertilizer applications between fall and spring has paid off for many producers in this area, according to Brandon Hebbert, who manages the MFA fertilizer plant in Ozark.

“P and K are not going to be mobile in your soil in the same way nitrogen is,” Hebbert explained. “So if you put it out in the fall and there’s any deficiencies, you’ve got all winter for those nutrients to start to break down and become available to the plant.”

While his location primarily applies P and K on pastures in the fall, Hebbert said some of the row-crop farmers in his area are seeing a benefit as well.

“We don’t have a lot of row crops around here, but some of the dairies have a few smaller fields,” he said. “In a lot of situations, the fertility is pretty low and they’re trying to get the most out of their yields. It takes a lot of fertilizer. By applying P and K in the fall, it helps stretch out resources for the farmer.” 

Post-harvest applications of fertilizer can also give row-crop farmers flexibility when their planting window is limited, he continued.

“Like I said, most of the guys who grow corn around here are dairy farmers, so they’ve already got a lot of their time spoken for,” Hebbert said. “Sometimes, having that P and K out there already can be the difference between getting a crop in or not.”

Brian Swadner, MFA’s precision specialist for the Ozark and Neosho area, said splitting applications of N, P and K not only aids plant health and gives producers better results, but it also allows MFA applicators to fill customers’ needs in the spring more efficiently.

“We want to be able to get out there and get the spreading and fertilizing done when the grower wants it,” Swadner said. “What we’ve been doing when we spread P and K in the fall kind of breaks up the normal schedule. When springtime hits, the stores are pretty busy spreading fertilizer. The variable-rate applications in the fall definitely help us to be able to provide the service to the customer when they want it.”

And, Hebbert added, it gives producers a little edge.

 “During green-up in the spring, we’re just a step ahead,” he said. “The producers who do this already have some of their starter fertilizer out there by splitting it before they put their nitrogen down. It just allows them to get a jump start and better yield overall.”

Improving pasture management on his family’s land has helped Gourley to grow the herd exponentially. He started with 16 heifers and a bull five years ago. The herd now numbers more than 900 head of cattle total. His ultimate goal is to be able to add 300-400 more head and run one cow per every two acres without supplementing his grass with feed.

“If you fertilize right, I believe your grass is going to grow. It should also have more nutrients which, in turn, should transfer to your cattle,” Gourley said. “Since we’ve started on the Nutri-
Track program, we’ve been able to run more head of cattle on less mineral, using less fertilizer because we have our soil in shape. I think that should be where everybody starts.”

For more information on the Nutri-Track program or fall fertilization, contact your local MFA Agri Services or AGChoice location. 

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