1999 Kentucky Wheat Crop Overview
Controlling Wheat Before No-Till Corn
Coincidence - Spring Aphid Sighting and BYDV
Changes in Cereal Leaf Beetle Thresholds
Soft White Winter Wheat for Kentucky
It is estimated that 650,000 acres of winter wheat were planted in Kentucky last fall for the 1999 crop. This is ~ 100,000 acres less than was planted for the 1998 crop. Acreage is down for a variety of reasons but primarily due to low prices received for the 1998 crop and a dim market outlook for the 1999 wheat crop. Although a majority of the planted acreage will be harvested for grain, some of the acreage will be harvested for silage or hay and a sizeable acreage will be used as a cover for spring planted crops. In 1998, 550,000 acres (73% of the planted acreage) was harvested for grain.
Dry conditions in August and September created less than ideal conditions for planting wheat. However, the majority of the crop was still planted on time. Rainfall was near normal in October and most areas of the state received sufficient amounts that were very beneficial; not only for establishment of the wheat already planted, but it also improved soil moisture conditions for intended wheat plantings that had been delayed because of dry soil conditions. Likewise, the October rainfall received at most locations occurred on a few number of days. This created more favorable days for field work and allowed most wheat plantings to proceed on time. Some wheat acreage did experience later than usual planting dates for several reasons (delayed harvest of late planted summer crops, extended dry conditions, or wet periods at some locations). Some later plantings also resulted from the prolonged mild conditions in late fall which allowed wheat plantings to continue.
Surprisingly, wheat stands were better than anticipated, considering the dry conditions that existed at planting time. The majority of the wheat acreage had stands that were average to mostly above average. Some poor stands did result in areas where dry conditions persisted or in portions of fields (hillsides, cloddy seedbeds). Overall, wheat stands were better in west Kentucky than other areas due to more favorable moisture at planting time.
Although rainfall was below normal in November and December, mild conditions in the fall permitted good crop growth and development. Temperatures were above normal in October, November and through mid-December with monthly air temperatures averaging 3 to 6 degrees warmer than normal during this period. Maximum air temperature averaged more than 60 degrees in November and close to 50 degrees in December. These extended warm conditions in the fall resulted in excellent plant growth and development prior to early winter dormancy. Tiller numbers were higher than normal with at least 3-4 or more fully developed tillers per plant on wheat that was planted on time and had adequate moisture for normal emergence. Even wheat that was planted later or had slow emergence and reduced early growth due to dry conditions, had adequate tillering because of the favorable, mild conditions in late fall.
Colder temperatures from mid-December through
mid-January halted crop growth and development. Some top growth and leaf
burn occurred, but no severe winter injury occurred to the wheat crop.
Some (very few) plants may have been lost that were shallow planted. January
rainfall was well above normal. Saturated soil and freezing/thawing conditions
may have resulted in some heaving losses of shallow planted wheat on poorly
drained soils. Overall, the wheat crop survived the winter in good to excellent
condition.
Warm temperatures prevailed from mid-January
through February. Monthly air temperatures averaged 6 to 8 degrees warmer
than normal during this period. In response, the wheat resumed growth.
This prolonged period of warm temperatures allowed growth to continue and
hastened crop development. This was reminiscent of last year when warm
temperatures in January and February of 1998 accelerated wheat growth and
development ahead of schedule. This caused a large portion of the wheat
crop to be at growth stages which were susceptible to freeze injury if
cold temperatures occurred. In mid-March of 1998, extremely cold temperatures
(20-25 degrees below freezing) did occur and resulted in extensive freeze
damage to a sizeable portion of the wheat crop.
Cooler temperatures returned in early to mid-March of this year (1999); however, as opposed to last year, the recorded temperatures were not low enough to cause freeze injury but were cool enough to cause wheat growth to cease and/or slow down. Because of the early, advanced wheat growth caused by the warm January and February, these cooler, early March temperatures were beneficial to slow wheat growth and needed to help avoid potential freeze injury. Likewise, most spring nitrogen applications were delayed this year, as opposed to last year, which was good management considering the freeze injury potential that existed due to the warm and accelerated growth conditions. Warmer temperatures returned again in mid-March. Although the potential for freeze injury still exists for this wheat crop up through mid-April, the greatest risk is hopefully past.
In early March, there were some concern about off-colored (yellow, purple) wheat in "wet natured" fields. The problem was determined as crop stress and limited nutrient uptake. The problem was temporary with no prolonged, detrimental effects. These fields have improved significantly with nitrogen applications and warmer temperatures.
Presently, the wheat crop looks very good. Good stands were achieved last fall; excellent tillering occurred prior to winter; winter survival was good; aphid populations have remained low; and no major disease problems have occurred so far. If no spring freeze or disease and insect problems occur, this wheat crop has excellent yield potential.
GRAMOXONE EXTRA: Wheat that is in the jointing stage is sometimes difficult to control with Gramoxone Extra. Adding atrazine will improve control of wheat, however, rainfall soon after application is needed to ensure root uptake of the triazine herbicide.
Since Gramoxone Extra is a "contact herbicide" good spray coverage will be essential to achieving optimum control of wheat. A minimum spray volume in the range of 15 to 20 GPA will probably offer better control than a spray volume of 10 to 15 GPA.
Gramoxone Extra at a rate of 2 pt/A applied with Atrazine at 1.5 to 2 lb ai/A has afforded effective control of wheat. Although similar results have occurred when Gramoxone was applied at 1.5 pt/A, the 2 pt/A rate is preferred for most cases.
Gramoxone Extra tends to offer more rapid
control and degradation of wheat vegetation compared with Roundup Ultra
and Touchdown. Because of this type of response, Gramoxone Extra may be
the preferred "burndown" herbicide when temperature is less than 50o
F.
ROUNDUP ULTRA and TOUCHDOWN 5 are translocated
herbicides and generally do not need the help of a triazine herbicide to
control wheat that is in the jointing stage. Control with Roundup Ultra
or Touchdown 5 tends to be slow and will require several days before wheat
is dead. The unusually warm temperatures that have occurred recently should
speed up the control from these herbicides.
Roundup Ultra and Touchdown 5 are translocated herbicides, consequently applicators may have some flexibility in using less water/acre compared with Gramoxone Extra. In many instances, a volume of 10 to 15 GPA will probably be adequate for Roundup Ultra and Touchdown 5.
Much of the UK research involving these herbicides has shown successful control of wheat when these herbicides are applied at rates ranging from 1 to 1.5 lb ai/A. Antagonism can sometimes occur when Roundup Ultra or Touchdown are tank mixed with other herbicides. Increasing the rate of the "burndown" herbicide usually helps overcome this antagonism.
Guidelines for specific rates of Roundup
Ultra and Touchdown 5 are indicated below:
Wheat Height
6"
12"
Roundup Ultra*
Alone
2.0 pt/A 2.0 pt/A
Tank Mixed 2.5 pt/A
3.0 pt/A
Touchdown 5*
Alone
1.6 pt/A 1.75 pt/A
Tank Mixed 2.0 pt/A
2.40 pt/A
*Observe the herbicide label for directions
on using ammonium sulfate as an additive. A nonionic surfactant may be
included with Touchdown 5, but should not be included with Roundup Ultra.
A final word of caution would be to check
for rotational crop restrictions for herbicides that were applied to wheat.
For example, any fields treated with Harmony Extra should not be planted
to corn until 60 days after application.
Question: I am seeing a few aphids, should I spray them to avoid BYD?
My Answer: No, it is too late. If you see
symptoms in several weeks it will not be from virus moved by the aphids
you are seeing now, but rather aphids feeding last fall or very early winter.
A few weeks pass and some BYD symptoms
appear. SEE!! I should have sprayed those aphids I saw in March. I didn't,
and now I have BYD.
My Answer: If you are seeing BYD symptoms
now, then you had BYDV in March, aphids or no aphids. Spraying that late
would have no affect.
In Kentucky BYD symptoms rarely show up
before spring, even though most infections and almost ALL important infections
began in fall or early winter. Spring aphids and spring BYD symptoms are
by in large coincidence. Almost all important BYDV infections need to be
controlled in the fall and early winter.
Now, separate from BYDV, if you observe
large numbers of aphids (most likely English grain aphid) during head filling
time then you need to control those aphids to avoid their feeding damage.
This has nothing to do with BYDV which is why so many more aphids are required
(50 per head) to result in an insecticide application.
You should note these changes in your copies of :
ENT-47 Insecticide Recommendations for Small Grains
ENTFACT-107 Cereal Leaf Beetle in Ky Wheat
ID-125 A Comprehensive Guide to Wheat Management in Ky (Section 8)
IPM-4 Kentucky Integrated Pest Management
Manual for Field Crops: Small Grains
The sections on insect descriptions and
biology in these publications are still appropriate, only the scouting
and thresholds have changed. The following changes will be incorporated
into the above listed publications as they come up for review and reprinting.
(Note: FGS = Feekes Growth Stage)
When to Scout: Begin scouting at
FGS 7 (two nodes present) This will generally be in very late March or
early April but will vary some with the season.
How to Scout: Samples of 10 tillers
should be examined at each of 10 randomly selected sites (100 stems per
field). The sites should be representative of the field as a whole. Check
all the leaves and stems for cereal leaf beetle eggs and larvae (grubs).
Record: Count and record the number
of eggs and larvae found on each tiller. Calculate the total number of
eggs and larvae found.
Threshold for egg/larval Counts:
Treat if you find any combination of 25 or more eggs and/or larva total
per 100 tillers. (An average of 1 per every four tillers or 0.25 per tiller).
Scouting Frequency: Under the high
management system, you want to catch the cereal leaf beetle population
at a time when most of the eggs have been laid. If your counts indicate
that more than 50% of the CLB are in the egg stage, then sample again in
5 to 7 days. Once more that 50% of what you find are larvae stage then
one scouting trip should be enough.
This sampling procedure has not changed.
However, the THRESHOLD HAS CHANGED.
If you are unable to complete the egg/larval
sampling scheme, then you should examine the crop for larval /adult damage
when the flag leaf is present. This procedure will prevent most yield reduction;
however, it is not as sensitive as the egg/larval method recommended for
the high management strategy.
When to Scout: Begin scouting by
at least FGS 8 (Flag) and continue through FGS 10.5 (flowering).
How to Scout: Examine 10 head-bearing
stems at a minimum of one location for each 10 acres of field size. Look
carefully at the top three leaves (Flag, F1 and F2) on each head-bearing
stem, for CLB larvae and/or adults.
Record: Count and record the number of larvae and/or adults on ten stems.
Threshold: Treat if you find an
average of ½ larva and/or adult per head bearing stem. (Or one larva
and/or adult for every two head bearing stems.)
The optimum time to apply insecticides (if the threshold is reached) is from after the appearance of the flag leaf (FGS 8) until the head emerges (FGS 10.1)
Do not apply insecticides if the threshold is not reached. Many wheat pests are held in check by natural enemies. When you apply an insecticide, these natural enemies will be killed.
Do not put an insecticide in with a nitrogen
application. This occurs too early. You will not get optimum control.
Consider if other insect pests are present
when choosing an insecticide. Depending up the pest pressure you may choose
one insecticide over another.
You may have heard recently about interest
in growing soft white winter wheat in Kentucky. The Kentucky Small Grain
Growers Association (KSGGA), Siemer Milling, and Bremner Bakeries have
teamed up to promote the idea. Why white wheat?
Soft white winter wheat has historically
been grown in the Pacific Northwest, as well as in the northern states
of Michigan and New York. Like our own soft red winter wheats, soft white
wheats tend to be low in protein, and they are used to make a diverse array
of products. In the Pacific Northwest, the Asian noodle market is the destination
of much of the soft white crop. In the eastern U.S., however, soft white
wheat is used to make cakes, crackers, cookies, pastries, quick breads,
muffins, snack foods, and certain crackers and breakfast cereals. Since
the end products of soft red and soft white winter wheats are so similar,
why are millers and bakers in Kentucky interested in buying locally grown
soft white wheat?
First, let's consider the basic difference
between red and white wheats. There are three genes that are involved in
seed coat color. Wheats that have all three red genes are a darker red
than wheats with only one or two of the red genes. White wheats simply
lack the red seed coat genes altogether. If you cross two red wheats that
have only one or two of the genes, it is possible to end up with a white
wheat from the cross. In other words, the only difference between red and
white wheats is this simply inherited genetic trait.
As so often happens in breeding, however,
there are some consequences associated with this simple genetic difference.
One consequence is that white wheats, for reasons not completely understood,
generally have poorer resistance to sprouting than red wheats during wet
weather at harvest. This is not true of all white wheats, and we have certainly
seen some red wheats in Kentucky, like 'Cardinal', which had poor sprouting
resistance. But in developing white wheats for Kentucky and the mid-south,
sprout resistance will be a high priority. Along with the reduced sprout
resistance of white wheats, comes a positive consequence. The tannins in
the red seed coat that give a bitter flavor to the bran are gone. Therefore,
whole white wheat products have a pleasant, nutty flavor that contrasts
with the bitter flavor of many whole red wheat products. This feature of
white wheats has fueled phenomenal interest in Kansas, where many speculate
that hard white winter wheats will eventually replace the hard red
winter wheats that have been grown there since the 1860's.
From the miller's standpoint, white wheat
has some advantages: the wheat can be milled closer to the bran, and the
bran itself is of a higher value because it can be used in breakfast cereals.
White wheat is attractive to the baker, as well, because the bran is not
bitter tasting, and more fiber can be included in the end product. This
meets the demand of our increasingly health-conscious society. Both millers
and bakers in Kentucky would prefer to buy locally grown white wheat to
save on transportation costs.
Eventually, it is thought that the advantages
of white wheats may drive both the HRW and the SRW regions away from red
wheats. The time frame for this change is long term. In the mean time,
where both red and white wheats are grown, it is essential that the two
types of wheat be segregated in commerce. This will require on-farm storage
and careful management. During this time of transition, there will be premiums
paid for white wheats. For more information about the Kentucky soft white
winter wheat program, contact Todd Barlow of the KSGGA at 1-800-326-0906.
-Leaves are opposite on square stems.
-Leaves have petioles and tend to be reflexed
or pointed down.
Henbit (Lamium amplexicaule)
-Leaves are opposite on square stems.
-Upper leaves have no petioles, while
lower leaves are on petioles.
Control: By now the majority of
henbit and purple deadnettle plants have bloomed or matured, consequently,
there is probably very little to gain economically by spraying these with
a postemergence herbicide. Mature plants will eventually die back as temperatures
become warmer.
While many of the newer grain conveyors are self cleaning, most of the equipment on grain farms must be cleaned by hand to remove the small amount of broken grain and dust that remains in the bottom of the housing. Again, a vacuum with a brush attachment at the end of the hose will make this tedious chore a lot easier. Some growers may use the first load of grain to clean out handling equipment at the beginning of harvest but this grain should be held separately and sold soon after harvest regardless of the price. It's better to loose a few cents on a few hundred bushels than to risk the chance of infesting an entire bin of wheat worth several thousand dollars.
Sanitation in and around bins and tanks is the most cost-effective method of protecting stored grain from insect infestations. For a few hours of time and energy spent in the right areas, thorough cleaning will go farther than some other more costly options. Bin sprays should be applied before adding grain to the bin to protect it from insects during storage. Thoroughly cover all surfaces inside the bin to the point of run off and spray the outside around the perimeter.
Insects thrive in a warm, humid environment. Because wheat is stored during hot, humid weather it must be held dry (12.5% moisture content) to retard insect activity even if it will only be held a few weeks. Since the base market level is 13.5% moisture, this reduced moisture creates a storage cost of about a nickel per bushel but this can usually be recovered by timely marketing.
Grain protectants will guard against insect pests for several weeks in the summer but their effectiveness is limited because these insecticides breakdown under high temperatures. A compromise approach to treating the entire bin is to treat only the top 12 inches of grain. This can be applied by mixing the protectant and grain with a rake or shovel but is more safely accomplished by applying the insecticide as the last load is augered into the bin.
Be aware that this 'cap out' treatment will only protect wheat from the most common surface infesting insects and may form a barrier against insects moving down through the grain. However, it will have no effect on insects that come in with the grain or those that enter through holes and cracks in the bin wall below the grain surface. Fumigation should be used prior to sale only when all other options fail to control insect activity.
If you make it to mid-September without any major insect populations, Mother Nature will usually provide an opportunity to cool stored grain to levels that provide good control (temperatures less than 60o F). Many growers, especially those who market wheat to millers or processors, actually prefer this chemical free option. Fans should be run about once a month during the fall to cool grain to within 10 degrees F of the monthly average temperature. Target temperature levels for stored grain in Kentucky should be 60, 50, and 40 degrees F in September, October, and November, respectively.
Inspection of stored grain rounds out the arsenal of cost effective weapons available to managers who annually wage the battle with insects. Always exercise proper safety precautions by locking out power to the unloading auger switch before entering a bin. Once inside, look for insects and signs of heating or moisture buildup under the surface of the grain pile at several different locations. If any of these problems are found it's usually best to run the fan to cool the grain or move it to another bin and clean it in the transfer.
The following list of top 10 practices
emphasizes economical insect control for stored wheat. This list represents
a lot of work and diligence on the part of stored grain managers, but the
rewards are fewer problems during storage and lower discounts when the
crop is sold.
TOP 10 PRACTICES FOR STORING WHEAT SAFELY AND ECONOMICALLY
1. Cleans bins thoroughly
before storing grain.
2. Harvest wheat at
a manageable moisture level for your operation (15% or lower if heated-air
drying is not available).
3. Adjust combines before
and during harvest to reduce kernel damage and limit trash.
4. Dry wheat to 12.5
% moisture content if it will be held one month or longer.
5. Clean wheat before
storing.
6. Remove peaked grain
in storage bins to provide uniform airflow through the grain.
7. Apply a 'cap out'
treatment to the top 12 inches of wheat.
8. Inspect wheat frequently
to check for insect activity and temperature or moisture changes.
9. Run fans to cool
stored wheat thoroughly after drying, as soon as possible in September,
and at least once a month in the fall.
10. Fumigate prior to sale ONLY
if above control measures fail and the number of live insects exceeds the
economic threshold.
For More Information, Contact:
Dottie Call, Wheat Group Coordinator
University of Kentucky Research and Education
Center
P.O. Box 469, Princeton, KY 42445
Telephone: 502/365-7541 Ext. 234
E-mail: dcall@ca.uky.edu