Preparing for the Winter Wheat Planting Season

Carrie Knott, Extension Agronomist-Princeton, University of Kentucky

The optimal planting window for winter wheat in Kentucky is quickly approaching: October 10-30. Prior to the physical planting of wheat, farmers must make several critical decisions to maximize wheat grain yield and profitability the following June.  

2016 UK Wheat Field Day Talks Available Online

If you were not able to attend the 2016 UK Wheat Field Day and would like to see what you missed click on the following you tube links:

Preemergence and Postemergence Control of Italian Ryegrass in Wheat
UKREC Extension Weed Science Specialist Jim "Chip" discusses preemergence and post emergence control of Italian rye grass in wheat. Chip's final presentation at Princeton Wheat Field Day before his retirement this summer! 

FHB Prediction Tool Upgrade

Don Hershman, Extension Plant Pathologist, University of Kentucky

Heads up! The new FHB (Head Scab) forecasting tool has a new feature.You can select the FHB susceptibility level of the variety you have planted.

Wheat Disease Management for 2015 Starts Now

Don Hershman, Extension Plant Pathologist, University of Kentucky

Wheat diseases reduce grain yield and/or quality in most years. Many wheat producers rely on foliar fungicides as their primary disease management weapon. Foliar fungicides are certainly an important disease management tool. However, pre-plant decisions made – that is, decisions being made right now for the 2015 wheat crop - have the greatest impact on which diseases develop during the season and to what extent. Thus, it is critical to make as many of the “right” decisions as possible to reduce the potential for diseases to reduce both grain yield and quality next spring.

For more on how pre-plant decisions impact disease potential, go to this link:
http://www2.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/ppfsagsg6.pdf

Head Scab Newsletter

The Wheat Science IPM Group Newsletter was released on June 4, 2009 with the latest information for mangaing wheat with Fusarium head blight (or head scab) this season.

The newsletter is available as a pdf at: https://www.ca.uky.edu/ukrec/newsltrs/News09-FHB.pdf

FHB Risk, May 7, 2009

An email from Don Hershman had the following image. The image is from the FHB Risk Assessment Tool at Penn State. http://www.wheatscab.psu.edu/riskTool_2009.html
Much of the wheat-growing area is in red or yellow, meaning that we have high to medium risk for FHB, according to the model.

See Don's post from May 6, 2009 for more details about head scab and management options.

FHB May Be Severe in Kentucky this Year

Wheat across central and west Kentucky (which makes up the bulk of the wheat acres in the state) has been in various stanges of flowering since early last week. Many fields are currently at full anthesis or slightly beyond.

As we all know, it has rained a lot over the past 5-8 days across much of the state. This wet weather, as well as temperature and humidty conditions, have resulted in a moderate to high FHB risk across most of central and west Kentucky. The windy weather before it started to rain, and now the rain, has greatly hindered fungicide applications aimed at Fusarium head blight suppression. Some spraying was probably possible on Monday and Tuesday of this week, but the current storm system moving through the state will effectively eliminate the possibility of ground spraying for today (Wed), probably tomorrow, and maybe into Friday-Saturday. Aerial application will also be challenged. The bottom line is that most wheat fields in the state will be highly vulnerable to FHB. By time spraying is possible again, it will be too late to spray most fields due to label restrictions. Plus, from a practical perspective, once infection has occurred, fungicides (which are not that good against FHB in the first place) are of little value.

I rarely prognosticate epidemics, but it seems that nothing is in our favor, and everything is pointing towards an significnat FHB episode in the state. Fields that were in full flower early last week may escape significant infection since they were beyond the most susceptible infection stage by the time the rains began. Likewise, crops that have yet to flower, may escape infection. But the acres that fit either of these two scenarios is rather small compared to the whole.

If it is any consolation, remember that when FHB pressure is high (such as I believe it is right now), fungicide-treated crops can still be severely impacted by both FHB and DON. That is, only 30-50% suppression can be expected when fungicides are applied under the best of scenarios. One final point. Some may be thinking that they wish they had sprayed while their crop while it was still heading out, but before flowering. Doing so would have provided little benefit against FHB due to the limitations of fungicides against FHB and the fact the new tissue that emerges after application would be (for all practical purposes), unprotected.

I am sorry to have to predict this gloomy situation. We will know how accurate my words are by mid-May. That is about how long it will take for FHB symptoms to be expressed.

Current Status of Fusarium Head Blight

Low temperatures and breaks between rain events (up until this past event) have kept the FHB predictive model from indicating even moderate FHB risk (up until now). The block of rain we have just experienced has changed that, so the FHB models are now showing moderate to high risk for spore release in much of central and west KY. I believe conditions will be ripe for spore release beginning Monday night. Spore release happens mostly happens at night and is actually favored more by high humidity than rain. Rain can give you splashing of spores, but it also washes spores out of the air and off of plants. Infection, on the other hand, requires free moisture, so infection generally is greater when spores have been released and transported to heads during dry, but humid, periods at night, followed by rain the next day or so to support infection. It is complicated and that is why we don't always have a lot of FHB. It is rather hard to get!

I encourage growers with decent crops that are just entering flowering to to spray as much as they can Monday and Tuesday and into Wed. I realize that getting sprayers into fields will be hard, so that is a complicating factor that may prevent many fields from being sprayed this year. It is what it is. More wet weather is anticipated beginning Wednesday. I have had several questions asking about how late one can spray and still get FHB suppression. That is pretty simple. Most labels restrict application to early flowering or at most 50% bloom. Thus, there is not much of a decision to make. The days to harvest restriction is very specific for all fungicides labeled for wheat.

The key thing to remember is that according to the FHB models, up to the present moment, not many spores have been available to spread to heads, let alone infect heads. But after today and the gloves come off unless it turns hot and dry fast. This could be a bad FHB year in light of the lack of spraying and/or difficulty in getting fields sprayed. But the timing of this rain coinciding with the completion of head emergence or flowering in many fields is hard to deal with. If fields had sprayed before the rain, it might have been too early to get good coverage on the heads.

Updated Wheat Scab Risk Management Tool

Our colleague, Don Hershman, said that the Fusarium Head Blight (Head scab) Risk Management Tool has been updated and is available at: http://www.wheatscab.psu.edu/riskTool_2009.html

The tool provides a general risk level for wheat in a given area.

Once into the tool, identify what date you want to select (such as today).
Then identify the wheat model (spring wheat or winter wheat).
Finally, select the state in the map that applies.

A color-coded map will appear with green being little risk, yellow being medium risk and red being high risk. This model can help when deciding to make a preventative fungicide application.