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Corn Newsletter : 2019 - 31
Listen to the Agronomy and Farm Management Podcast while driving to the 37th Farm Science Review
If you are heading down to the 37th Annual Farm Science Review, listen to the Agronomy and Farm Management Podcast on the way! We interviewed the FSR manager, Nick Zachrich, about what is new this year and also talked to the farm manager, Nate Douridas, on what will be featured in the field demonstrations. You can also learn about all the areas where Extension brings you resources, presentations, demos and more. Come out and see us! https://agcrops.osu.edu/video/agronomy-and-farm-management-podcast
Managing Take-all and other Diseases in Wheat after WheatAuthor(s): Pierce Paul
I never recommend planting a small grain crop after another small grain crop, as planting wheat after barley for instance or barley after wheat increases the risk of diseases such as head scab and take-all. However, this year, some growers do not have much of a choice; soybean will not be harvested in time in some fields for them to plant wheat, so they will either have plant wheat after corn harvested for silage or after wheat. If you do end up planting wheat after corn or wheat, here are a few tips that could help to reduce the risk of having major disease problems next spring:
- Select and plant the most resistant variety that you can find. Check the Ohio Wheat Performance Trials report (https://www.oardc.ohio-state.edu/wheattrials/table6.asp?year=2019), and select a variety with resistance to as many diseases as possible. Give priority to head scab, Stagonospora, and powdery mildew resistance.
- If conditions become favorable for disease development in the spring, resistance alone will not control head scab. Plan to apply a fungicide if it becomes wet and humid during flowering. However, we still have time to think about fungicide application for head scab control, let us continue to explore fall management options.
- If you cannot rotate away from a small grain crop, the next best option to reduce spore build-up in the field is tillage. Most of the common leaf and head diseases in Ohio and even some root diseases survive in crop residue. Tillage will bury residue, leaving fewer spores available to infect the newly planted crop. Tillage will also speed-up residue decompositions.
- Plant after the Hessian fly-free date, as cool fall conditions are less favorable for spore production and infection. See the article Considerations for 2019 wheat planting by Andy Michel, Laura Lindsey and Pierce Paul for more on planting date.
Planting date and foliar fungicides will not control root diseases such as take-all, and wheat and barley varieties with resistance to talk-all are hard to find. So, here are a few additional tips that will help to reduce take-all problems next spring, if you happen to plant wheat after wheat or another small grain crop this fall:
- Nutrient management: Take-all is favored by nitrate forms of nitrogen and suppressed by ammoniacal and slow-release forms of nitrogen. Manganese deficiency has also been associated with increased levels of take-all. In general, any form of nutrient stress (lack of essential and trace elements) could increase take-all.
- Soil pH: Take-all it is also favored high pH, so applying lime will generally increase take-all, particularly if the pH is elevated above 6.
- Tillage will help to reduce take-all for all the reasons listed above.
- Crop rotation away from small grain crops for 1-2 seasons is often the best way of managing take-all, with soybean being one of the best rotational crop. However, if you plant wheat or barley into a(n) (abandoned) soybean field that had a lot of grassy weeds you could still have problems with take-all.
Considerations for 2019 Wheat Planting
With the autumn rapidly approaching, wheat planting is likely to begin soon. Planting after the Hessian fly free date remains the best chance to avoid issues with insects and diseases, as well as helping ensure good agronomic quality. Some benefits of the fly free date:
Hessian Fly: Adults of the Hessian fly lay eggs in emerging wheat. These eggs then hatch into small larvae that feed before spending the winter as a flaxseed. The early autumn feeding will stress the young wheat plant right before the winter, resulting in stunted and wilted plants. Very little egg laying occurs after the fly free date, which helps to limit infestation. Wheat varieties with resistance against the Hessian are available, in addition to seed treatments, which can help limit damage.
Aphids: Two main aphids infest wheat in Ohio: the English grain aphid and the bird cherry-oat aphid. These aphids rarely cause economic injury on wheat from feeding. However, they can transmit several viruses that can severely impact wheat including Barley Yellow Dwarf virus. These aphids do not only feed on wheat, but several other grasses that serve as natural sources of viruses. If wheat is planted too early, and emerges before the aphids overwinter or stop feeding, they can be early transmitters of viruses. Although seed treatments could help kill the aphids, they may survive long enough to transmit the virus to the plant. Any transmission in the autumn would likely serve as a local source in the following spring.
Other foliar diseases: Although not directly related to the Hessian Fly, planting after the fly free date also helps to reduce the early establishment of leaf diseases like Stagonospora leaf blotch and powdery mildew. Planting date is indirectly linked to spore production by fungi that cause these diseases and infection of young plants. The earlier you plant, the more spores are available, and the more suitable (warmer) conditions are for infection. Fall infections often leads to more damage and greater yield loss in the spring, especially of susceptible varieties are planted and not protected with a fungicide at Feeks 8 (flag leaf emergence). As conditions become cooler after the fly free date, pathogens that cause leaf diseases become last active, and as such, are less likely to infect plants.
Above normal temperatures will continue for the rest of SeptemberAuthor(s): Jim Noel
After a cooler start to September it was expected to be warmer than average and that has happened and will last the rest of the month. Highs will generally be in the 70s and 80s north half and in the upper 70s to near 90 range in the south half. Lows will generally be in the 50s and 60s. This will be several degrees above normal.
The first half of September was expected to be drier with a trend to normal or wetter weather in later September. Indications are that we will remain at or below normal rainfall for most of the state for the remainder of September. Over the next two weeks, rainfall is forecast to be mainly an inch or less with normal being 1.0-1.5 inches. The main rain areas will be off the southeast U.S. coast and in the upper Midwest as the attached two week rainfall graphic shows. High pressure will remain in control of a good portion of the southeast third of the U.S. as tropical activity off the U.S. Southeast Coast will help strengthen the high pressure in the Southeast.
Probabilities support our first first freeze at or later than normal for this autumn. Typically it occurs in the Oct. 10-20 range for much of the state. It is highly unlikely we will see anything before Oct. 10.
Looking at October, we expected near to slightly above normal and rainfall not too far from normal.
About the C.O.R.N. Newsletter
C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.
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