USA
March 28, 2012
This winter’s sporadic snow cover across the Northern Plains and inconsistent temperatures in the Pacific Northwest (PNW) have prompted Syngenta and university extension agronomists to closely monitor the development of winter wheat crops as spring 2012 quickly descends upon us.
With the help of expert agronomists and field findings, wheat growers are urged to identify the degree of winterkill damage and to then employ appropriate follow-up actions. While reports of winterkill have emerged from the Northern Plains, it is important to distinguish the damage from other potential problems, including snow mold, barley yellow dwarf virus, salt damage, frost injury or even Pythium.
Experts note that these diseases are often difficult to tell apart. Pythium, for example, will not kill plants outright, but rather colonize roots and cause uneven crop growth throughout the field. Winterkill, on the other hand, tends to encompass and destroy larger, more general areas of the field and impacts plants that are left unprotected by snow cover.
Overall, though, the process of gaining and losing winter hardiness is gradual, making it critical to carefully evaluate growing conditions and viable solutions before implementing any drastic measures. Jill Henshaw, a Syngenta Agronomy Service Representative in the High Plains region, explained that properly identifying issues in the field can mean the difference between having a successful crop and not having one at all.
“The impact of improperly identifying winterkill versus disease or insect damage will be reflected in a grower’s ROI and the management decisions he or she needs to make very soon,” Henshaw explained.
Identifying injury
Typically, soil-insulating snow cover is critical to the survival and success of winter wheat. This season, a general lack of snowfall across the Northern Plains and erratic temperatures in the PNW have triggered concerns among wheat growers, leaving many wondering how to best proceed with spring management plans.
Before taking extreme action this spring, such as destroying winter wheat stands and replanting, wheat growers should identify and evaluate the degree of winterkill injury to adjust next steps accordingly. Symptoms to closely observe include: plants with one or more dead leaves; patches of dead plants in the field; tiller development without accompanying root system growth; and wilting, yellow and dying of some leaves after spring green-up.
University of Minnesota Extension Small Grains Specialist Jochum Wiersma advised that wheat producers wait until plants break dormancy and fields begin to green up before finalizing any replanting decisions. In the meantime, growers could check the viability of their wheat crowns every two weeks as part of their early injury assessment. Generally, wheat roots are less winter hardy than crowns, and regrowth may be delayed.
“Simply dig up the crowns, wash them off, cut off the dead top growth, place it on a moistened paper towel and place everything in a plastic bag to prevent drying out. Then just wait for them to break dormancy at room temperature,” Wiersma explained. “If they’ll grow leaves again within just a few days, the crowns are still viable.”
As growers return to the fields, North Dakota State University Extension Agronomist Joel Ransom stressed the importance of crop stand and quality assessments. “If substantial winter injury has occurred throughout the field, an alternate spring crop strategy should be considered,” Ransom said. “If crop injury is uniform across the field, then the threshold is 40 percent stand. If the stand is less than 40 percent, it would mean planting another crop, like spring wheat or soybean, instead.”
According to Wiersma, the goal is to establish a fall stand of about 25 plants per square foot. Growers can sustain up to 40 percent stand loss if the stand loss is even; however, winterkill is not typically uniform. In situations where damage is patchy, Wiersma recommends thinned or damaged stands are worked up individually, as opposed to tearing out an entire field and replanting. This remedy will take careful management but is a workable alternative. However, as Wiersma mentioned, it is important to avoid inter-seeding spring wheat with winter wheat as that can create marketing problems at the end of the season.
“Still, growers should wait until the end of April to take action. The plant-sampling viability survey is a nice tool to use in the interim, and perhaps the only way to assess this damage at this point; however, it does not give growers insight to their whole field,” Wiersma noted.
Springing into spring
The unseasonably mild winter has set the tone for an early spring in parts of the Northern Plains. Experts estimate an earlier spring than usual, as the weather so far has been mild and relatively dry. “An early spring means growers can get out into the field earlier to plant and fertilize, which is generally better for small grains,” Ransom said.
In the PNW, however, weather conditions and temperatures continue to fluctuate, and spring may turn out to be relatively normal. Tim Murray, plant pathologist at Washington State University, explained that while historically winterkill has frequently occurred in February and March, the sporadic snowfall and relatively cool temperatures have offset winterkill concerns this year.
A greater threat is stripe rust in both winter and spring wheat. “Stripe rust will definitely be on growers’ minds this season as conditions so far have been favorable in terms of overwintering potential,” Murray said.
Growers in the PNW have experienced high levels of stripe rust over the past two years, and many have since adjusted their management strategies accordingly. “Wheat growers have been more proactive about spraying fungicide early and tank-mixing with a herbicide,” Murray explained. “In these conditions, growers are also far better off choosing varieties that are resistant and using a fungicide to protect the yield potential of that variety.”
In addition to stripe rust, growers in the PNW should monitor for eyespot or “strawbreaker” in their winter wheat. “It’s a fungal disease that infects the stem base and causes lodging later in the season. There’s a potential for the disease to develop, and if growers see it, spray a fungicide for control,” Murray said.
Management considerations
When Mother Nature is unfavorable, selecting certified, winter-hardy wheat varieties specifically developed for their region, such as AgriPro® Hawken for the Northern Plains and Whetstone for the PNW, can help shield the crop against risks of winterkill and other winter-related injuries. “Reports from South Dakota are telling of Southern winter wheat varieties succumbing to the stresses of a northern winter,” Henshaw said. “Therefore, it’s critical to select winter wheat varieties bred to cope with your climate. Growers can’t impact their current crop, but it is a factor they’ll need to consider in the coming months as the next winter wheat cycle approaches.”
For better stand and seed establishment, seed treatments, such as Dividend Extreme® seed treatment fungicide and Cruiser® seed treatment insecticide, are instrumental in protecting seedling and root development and in establishing a strong foundation for the crop. “Seed treatments are an invaluable insurance investment. Many diseases, like Pythium and Fusarium, could be avoided with the proven fungicides found in Dividend Extreme and CruiserMaxx® Cereals. The fungicides found in these products are systemic and provide a barrier of protection around the seed and seedlings against early-season pests,” Henshaw explained.
Helping wheat to emerge and overwinter better, Cruiser products also deliver the patented Cruiser Vigor Effect, which aids in producing more robust and vigorous plants, even in the absence of insects. “Experts are predicting an increase in pest pressure this year due to the open winter, and the winter wheat crop has already had a tough start. Growers should be thinking about the best management practices to reduce stress on their crop,” Henshaw noted.
To minimize lodging concerns caused by adverse weather or taller plants with higher nitrogen levels, Syngenta has brought Palisade® 2EC plant growth regulator to the wheat and barley market for the first time this season. And to address foliar disease, an application of Tilt® fungicide at herbicide timing can help protect cereal crops from early diseases both on and in the plant, too. Tilt is an easy tank-mix partner with herbicides like Axial® XL and Axial Star, as well as insecticides and/or fertilizers. The added insurance application of a quality fungicide helps reduce stress to the crop and grower, too.
To protect the valuable flag leaf, Quilt Xcel® and Quilt® fungicides are also helpful tools for controlling rusts and other diseases. “With the potential for our wheat crops, it’s critical that growers manage them appropriately to achieve high yield, quality and profit,” Henshaw said. “Applying one of our Quilt fungicide brands will help growers protect the investment in their crop and maximize yields. Growers also receive added Plant Performance™ benefits that enable the crop to ‘breathe easier’ by improving the plants respiration process and increase water and nitrogen use efficiency so the crop can put all its energy to producing grain rather than fighting disease,” Henshaw explained. “The more growers invest in their crop, the more they will get out of it,” she added.
While peaks and valleys in temperatures and weather conditions can be concerning to wheat growers, patience and careful observation are essential. Before taking drastic action to address suspected winterkill this season, Syngenta cautions growers to carefully gauge the percentage of damage done (injury threshold); strategically select winter hardy varieties going into next season; and pick proper seeding dates based on region and weather conditions to maximize yield and quality potential. Syngenta also encourages growers to take a proactive management approach with their winter and spring wheat crops to capitalize on the profit potential these crops bring to their farms.
Plant Performance assumes the presence of disease pressure.
Important: Always read and follow all bag tag and label instructions before buying or using Syngenta products. The instructions contain important conditions of sale, including limitations of warranty and remedy. Some crop protection products and seed treatments may not be registered for sale or use in all states or counties. Please check with your state or local extension service before buying or using Syngenta products. Palisade 2EC is not currently registered for use or sale on wheat and barley in all states. Please check with your state or local extension service before buying or using this product. Axial®, AgriPro®, Cruiser®, CruiserMaxx®, Dividend Extreme®, Palisade®, Plant Performance™, Quilt®, Quilt Xcel® and Tilt® are trademarks of a Syngenta Group Company.
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