Friday, March 17, 2017

Varietal Differences in Freeze Damage

Dave Van Sanford, Wheat Breeding and Genetics, University of Kentucky and Bill Bruening, Small Grain Variety Testing, University of Kentucky
The wheat varieties we grow in KY will respond differently to the extremely low temperatures we have experienced over the past few days. Several traits come into play but the most important thing
for the grower to consider at this point is growth habit, which can range from completely prostrate to very upright.

Most of the wheat varieties grown in KY develop at a rate that is determined by heat units accumulated, which we commonly refer to as Growing Degree Days (GDD). These varieties were pushed by the unusually warm temperatures we experienced in February, so that many of them had reached jointing (Feekes 6) or beyond when the severe freezes began. A much smaller percentage of our wheat varieties are held back by sensitivity to daylength. These daylength sensitive varieties will not joint until they reach a daylength threshold – i.e. a minimum no. of hours of daylight. Such sensitive varieties remain prostrate in their growth habit until the threshold is reached and thus the growing point remains near the soil surface and is much more protected than the growing point in an upright variety at jointing or beyond.

Estimated Yield Potential for KY’s Freeze Damaged Wheat

Carrie Knott, Extension Agronomist-Princeton, University of Kentucky
Bill Bruening, Small Grain Variety Testing, University of Kentucky
Dave Van Sanford, Wheat Breeding and Genetics, University of Kentucky
Lloyd Murdock, Emeritus Extension Soil Specialist, University of Kentucky

After several nights with temperatures near or below 24°F the jointed stems of KY’s wheat crop are probably terminated by cold temperatures. We now have to decide what to do with our freeze damaged wheat crop.

Thursday, March 16, 2017


Edwin Ritchey, Extension Soil Scientist, University of Kentucky

The University of Kentucky Wheat Science Group will hold a Wheat Field School – EMERGENCY
WHEAT FREEZE EVENT at the UKREC in Princeton KY. This free program consist of a series of
short information sessions as well as a hands-on training to assess wheat damage in the field. UK specialists suggest that participants attending the meeting in Princeton bring whole plant wheat samples from their farm to assess and compare to non-damaged wheat.

Topics include: Wheat Freeze Overview, Economic Considerations, Chemical Residues and Future Implications, Nitrogen Contribution to Corn if Wheat is Terminated, Livestock Feeding Potential if Grain is Not Harvested, Plant Dissection for Freeze Damage Demo, Question and Answer Session, Hands-On Wheat Freeze Assessment.

For more information please click here or call Kelsey Mehl: 270-365-7541 ext. 200 or Colette Laurent: 270-365-7541 ext 264.

Wednesday, March 15, 2017

Assessing Winter Wheat Freeze Damage

Carrie Knott, Extension Agronomist-Princeton, University of Kentucky

Last night temperatures dipped below 24°F for several hours throughout Kentucky. Winter wheat at the jointing (Feekes 6) growth stage, was likely damaged by these cold temperatures.

To assess wheat freeze damage:

1. Wait until high temperatures are at least 40°F for 5 to 7 days. According to the projected weather forecast, most of the state will have high temperatures greater than 40°F the next 7 days. Assess freeze damage next Tuesday or Wednesday. Any earlier than the middle of next week may provide an inaccurate estimate of damage.

Thursday, March 9, 2017

2017 Revenue Protection Insurance Projected Prices for Corn and Soybeans and Safety-Net Decisions

Todd Davis, Extension Economist, University of Kentucky
The projected prices for Revenue Protection (RP) crop insurance is established using the December 2017 corn and November 2017 soybeans futures contracts closing prices for the month of February.
Figure 1. 
2017 and Previous Years Corn Revenue Guarantee 
($/Acre) Compared to Total Variable Costs (Red line) 
and Total Variable Costs plus Rent (Black Line) at a 
150 bushel/Acre APH Yield
The 2017 projected prices for corn and soybeans are $3.96 and $10.19 per bushel, respectively. The
revenue guarantee provided by RP insurance for varying coverage levels are compared to the budgeted cost of production and the cost of production plus cash rent to analyze the risk protection provided by RP insurance.

The rainbow of colored columns in Figure 1 and Figure 2 represent the RP insurance revenue guarantees provided for the 2013 (dark blue), 2014 (dark red), 2015 (green), 2016 (orange), and 2017 (light blue) crop years. The multi-year comparison illustrates how the crop insurance safety net has declined over the last five years as ending stocks for corn and soybeans have rebuilt after the 2012 drought. The red line is the 2017 budgeted per acre input costs, and the black line is the input costs plus budgeted cash rent. The corn and soybean APH yields are 150 and 55 bushels/acre, respectively, for Figure 1 and Figure 2.

Sunday, February 26, 2017

Freezing Temperatures Overnight May Damage Winter Wheat at Advanced Growth Stages in KY

Figure 1. Wheat heads showing freeze
damage at heading (Feekes 10.5)
Carrie Knott, Extension Agronomist-Princeton, University of Kentucky

Last night temperatures dipped to or below 24°F for several hours at many locations throughout Kentucky (Table 1). For winter wheat that has reached the jointing (Feekes 6) growth stage, damage (Figure 1) can occur to the developing wheat head, which is above the soil surface at jointing, when temperatures are 24°F or below for at least 2 hours.

Wednesday, February 22, 2017

Wheat: Earlier Aphid Occurrences May Be a Consequence of the 2017’s Warm Winter

Raul VillanuevaExtension Entomologist, University of Kentucky 
Figure 1. Pictures of the bird cherry oat aphid and
 a winged English grain aphid found in wheat fields
 in February 2017. (Photo credits Yaziri Gonzales).
In Kentucky there is a complex of aphid species that feeds on wheat. The bird cherry oat, the English
grain (Fig.1), the greenbug, and the corn aphids are the most important species. Their role as vectors of plant viruses, particularly Barley Yellow Dwarf Virus (BYDV), branded them as the key pest on
wheat grain production. These aphid species overwinter as nymphs, and can be active when temperatures are above 45⁰ F. It is known that BYDV infections are more damaging when they occur in early growth stages of the wheat plant. Thus, aphids have more opportunities to infect young plants under this climatological circumstances.