Lebanon Crop Management Video

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13 June 2011

Dampening Off Potential in Pa?

I have recieved two calls pertaining to the main stem being water soaked and beginning to die back.  Here is an article detailing seedling and larger plant disease that I thought might be important.

Del Voight

]http://www.extension.iastate.edu/CropNews/2011/0607robertson.htm

Hail on Corn

Folks thought you might appreciate some resources pertaining to hail on Corn.

By Roger Elmore, Department of Agronomy
Corn progress is back on track thanks to recent warm weather. This is indicated by heat unit accumulation for May 1 planting dates hovering slightly above average (107 percent of average statewide). Corn development across the state ranges from about V2 to V9 (second to ninth leaf stages) thanks to the wide range of planting dates this year.

And then thunderstorms hit on June 9 and pounded the corn; some of the thunderstorms were accompanied by severe hail. Plant growing points are still underground for corn plants at V6 (sixth leaf stage) and younger. This fact helps the plants survive early-season hail events even if the leaves are totally destroyed.

Be patient if your field has hail damage. The short-term weather forecast for warm and sunny weather plus the moisture received from the storms should encourage rapid and healthy regrowth. Plants V6 and younger should survive. Assess more developed plants carefully. The following links provide more detailed information:

Hail Industry staging systems differs

Be aware that hail industry corn staging systems differ from the leaf collar system most University Extension and researchers use. Table 2 in the Corn Growth and Development publication provides a comparison. (Click this to order publication on corn growth and development.)

In brief, the ‘horizontal leaf‘ method used by the hail industry is about one to two stages ahead of the leaf collar system from V2 to V8. That means a V8 plant in the leaf collar system is similar to a V10 plant in the horizontal leaf system. This is important when you use tables like those included in the University of Nebraska publication referenced above.

For more information other corn issues, see our ISU Extension Corn Production website. Look in the ‘Image Gallery” under ‘Crop Diagnostics’ for images of damaged corn from previous hail events.

08 June 2011

Scab in wheat

Grain Sampling for DON Analysis
What is DON?
Deoxnivalenol (DON), sometimes referred to as vomitoxin, is a mycotoxin

that may be produced in wheat and barley grain infected by the Fusarium head blight (FHB

or scab) fungus,
Fusarium graminearum. The occurrence of FHB in the field does not

automatically mean that DON is present in the grain, but a high level of infected kernels in

the harvested grain means DON likely will be present. The US Food and Drug

Administration (FDA) has established DON advisory levels to provide safe food and feed.

In addition, the grain and malting industry may have more rigorous standards for DON

levels in their purchased grain.

How is DON determined?
DON is measured in grain via several laboratory methods,

such as ELISA (Enzyme Linked Immunosorbent Assay), a FluoroQuant test, or gas

chromatography-electron capture (GC-EC) and gas chromatography-mass spectrometry

(GC-MS) analytical methods. Grain elevators, private labs, grain industries, and university

testing labs may provide these tests. Regardless of methods used for analysis, the key to

getting reliable and representative DON results lies with grain sampling. Sampling error

can be a significant source of variation in DON levels.

Grain sampling for DON determination begins in the field and continues at the elevator

or mill.

Field harvest effects on DON results:
Producers may reduce the risk of high DON levels

in the majority of their harvested grain by careful harvest methods. Often field margins or

low levels of the field have been shown to have higher FHB severity and DON levels, in

part due to possibly denser stands along field margins (headlands area) or because of higher

prolonged humidities in low lying areas. Producers may chose to harvest these areas

separately from the majority of their field, thus keeping more diseased grain separate from

sounder grain, and reducing the risk of higher DON levels throughout the majority of

harvested grain. In addition, producers may choose higher air speeds on their field

combines, to prevent the low test weight, scabby kernels from being harvested. Postharvest

grain cleaning also is an option for removing low test weight infected kernels,

especially if gravity tables are available.

Grain sampling at elevator or mill to get representative DON
: To achieve a more

accurate DON level estimate, it is critical that the collected grain sample be representative

of an entire truckload or bin of grain. Grain and other particles, such as weed seeds,

separate based on particle size and density as they flow and settle into a truck or bin.

Smaller, denser material often may be is found the center of the truck or bin, and this is the

material that is often higher in DON content.

End-gate sampling:
For sampling from an end gate grain stream, samples from

the entire width and depth of the grain stream should be collected, not just the first and last

portion of the load. A Pelican sampler or other sampling device aids in proper sample

collection and at least four samples of the entire grain stream should be collected at

intervals to represent spatial different portions of the load.

Probe sampling:
The probe is the only sampling method approved by USDAGIPSA

(United States Dept. of Agriculture’s Grain Inspection Packers & Stockyards

Administration) for stationary lots.
Multiple (5-10) probe samples are generally

recommended to obtain the best representative samples. GIPSA has specific

recommendations for probe sampling of trucklots of barley and wheat for DON. Included

in these recommendations are descriptions of sampling probes, sampling patterns, and

sample preparation, including appropriate cleaning, dividing and grinding of the samples.

Probes should not be taken from the center or outer portions of a load because these areas

do not reflect a cross section of the load. Also, GIPSA recommends a minimum 100 gram,

cleaned sample be used for testing. GIPSA’s specific guidelines can be found at the link

listed below. Other useful web-based links on grain sampling and DON also are provided.

USDA-GIPSA

Testing Trucklots of Barley and Wheat for Deoxynivalenol (DON)

http://www.gipsa.usda.gov/GIPSA/documents/GIPSA_Documents/don.pdf

NORTH DAKOTA STATE UNIVERSITY

DON (Vomitoxin) in Wheat -- Basic Questions and Answers

http://www.ag.ndsu.edu/pubs/plantsci/pests/pp1302w.htm

OHIO STATE UNIVERSITY

Where to Send Grain Samples for Mycotoxin Analysis

http://www.oardc.ohio-state.edu/ohiofieldcropdisease/wheat/mycotoxin%20text2.htm

MICHIGAN STATE UNIVERSITY

How to Sample Wheat to Accurately Determine Vomitoxin Levels

http://web1.msue.msu.edu/imp/modab/26309701.html

US WHEAT AND BARLEY SCAB INITIATIVE (USWBSI)

Early Detection of Deoxynivalenol in Wheat

What is DON?

Deoxynivalenol (DON), commonly referred to as vomitoxin,

is a mycotoxin that may be produced in wheat and barley

grain infected by Fusarium head blight (FHB) or scab. FHB

may infect grain heads when wet weather occurs during

the flowering and grain filling stages of plant development.

The occurrence of FHB does not automatically mean that

DON is present, but a high level of scabby kernels in the

harvested grain means DON will likely be present. Levels

of DON do not necessarily correlate with levels of physical

damage in grain.

What are the critical levels

of DON for use in food and feed?

The concentrations of DON in grain are expressed as parts

per million (ppm). One ppm is equivalent to 1 pound in 1

million pounds, 1 penny in $10,000, 1 minute in two years,

or 1 wheat kernel in 80 pounds of wheat.

The U.S. Food and Drug Administration (FDA) has

established DON advisory levels to provide safe food

and feed. Unlike aflatoxin in corn, DON is not a known

carcinogen. Furthermore, grain with DON would have to

be ingested in very high amounts to pose a health risk to

humans, but it can affect flavors in foods and processing

performance.

Human food products are restricted to a 1-ppm level

established by the FDA. This level is considered safe for

human consumption. The food industry often sets standards

that are more restrictive. DON causes feed refusal

and poor weight gain in some livestock if fed above the

advisory levels. FDA advisory levels are as follows:

1 ppm Finished wheat products, such as flour, bran

and germ, that potentially may be consumed by

humans. The FDA does not set an advisory level

for raw grain intended for milling because normal

manufacturing practices and additional technology

available to millers can substantially reduce DON

levels in the finished wheat product. However,

individual millers or food industries may have

stricter requirements than 1 ppm.

10 ppm Grains and byproducts destined for ruminating

beef and feedlot cattle older than 4 months and

for poultry, providing that these ingredients don’t

exceed 50 percent of the diet

5 ppm Grains and grain byproducts destined for swine,

providing that these ingredients don’t exceed 20

percent of the diet

5 ppm Grains and grain byproducts destined for all other

animals, providing that these ingredients don’t

exceed 40 percent of the diet

How does DON impact wheat grain

quality and product performance?

FHB infection during very early kernel development can

reduce yield by decreasing kernel numbers. Slightly later

infections cause shrunken, chalky white or discolored

scabby kernels, which often are referred to as tombstones.

Kernels infected late in their development by FHB may

show no visible damage, but still have elevated levels of

DON. A Canadian study (Sinha & Savard, 1997, Can. J. of

Plant Path. 19:8-12) of DON in FHB infected wheat kernels

found an average level of 1 to 1.2 ppm in normal appearing

kernels, 2 to 5 ppm in shriveled kernels, 174 ppm in white

tombstones, and 274 ppm in pink tombstones.

Basic Questions and Answers

Dwight Aakre,
Farm Management Specialist

George Flaskerud,
Crops Economist/Marketing Specialist

Ken Hellevang,
Agricultural Engineer - Post Harvest/Structures

Greg Lardy,
Beef Cattle Specialist

Marcia McMullen,
Plant Pathologist

Joel Ransom,
Agronomist

Brian Sorenson,
Crops Quality Specialist

Andrew Swenson,
Farm and Family Resource Management Specialist

In cooperation with the N.D. Wheat Commission

North Dakota State University, Fargo, North Dakota 58105

SEPTEMBER 2005

PP-1302

DON (Vomitoxin) in Wheat

The majority of the DON is present in the seed coat or

bran in wheat. For the flour miller, shrunken kernels result

in a loss of milling yield because damaged kernels are

removed to improve flour quality and reduce DON content.

Enzymes found on scabby kernels can break down protein

and consequently reduce gluten strength and adversely

affect the bread and pasta making properties of the flour.

Processing and final product quality, however, are not

significantly affected by DON per se when levels are below

1 ppm. In addition, the process of milling wheat into white

flour or durum semolina typically results in the reduction of

DON by approximately 50 percent. Therefore, many grain

handlers or processors purchase grain with DON levels up

to 2 ppm without discounts. Manufacturers of whole-grain

foods will have specifications that are more rigid.

Most export markets have specifications built into their

purchase agreements to limit DON levels. The typical

standard used by the majority of world buyers is 2 ppm

maximum. In Europe, some countries have lower limits,

such as 1 ppm in the United Kingdom and 0.5 ppm in

Norway, due to their own advisory levels. Japan has set a

maximum DON level on imported wheat of 1.1 ppm. A

complex formula was developed by the Japanese Department

of Health to limit the per capita consumption of DON.

How is DON Measured?

DON is measured using several laboratory procedures.

The most common method used by the Federal Grain

Inspection Service (FGIS) and most grain handling and

processing facilities is the immunological-antibody method

called ELISA (Enzyme Linked Immunosorbent Assay)

because it is relatively fast and cheap. The gas chromatography

- electron capture (GC-EC) analytical method is

quantitative and used to calibrate ELISA test kits. It also is

the method used by the NDSU Veterinary Science Toxicology

Laboratory for measuring DON presence in grain

samples. Factors, such as sampling differences, wheat

cleaning, sample preparation and test kit standard error,

may cause differences in results between testing laboratories,

but each lab and elevator follows approved methods

that are periodically conformance tested.

Is the sampling procedure for

DON analysis important?

The reliability of testing is greatly influenced by the

sampling procedure. To achieve a more accurate DON

level estimate, it is critical that the collected grain sample

be representative of an entire truckload or bin of grain.

Grain and other particles separate based on particle

size and density as it flows into a truck or bin. Typically, the

smaller, denser material is near the center and the larger,

lighter material is near the outside of the container.

Therefore, it is expected that there will be a variation in

the concentration of affected kernels in various portions

of a truckload. In addition, since DON levels can vary

greatly between kernels of similar size and density, it is

important to take several samples from various locations

within the load.

Probe samples should not be taken from the center

or outer portions of a load because these areas do not

reflect a cross section of the load. The samples also must

represent spatially distinct areas of the load. The probe

should collect the sample from as much of the entire depth

of the truck as possible. Four to five probes per truck are

recommended.

To obtain an accurate sample from an end gate grain

stream, samples from the entire width and depth of the

grain stream should be collected, not just the first and last

portion of the load. A Pelican sampler or other sampling

device aids in proper sample collection. At least four

samples of the entire grain stream should be collected at

intervals to represent spatially different portions of the load.

What are possible strategies

for using wheat with DON?

CLEANING

Is grain cleaning economically feasible for removing DON?

FHB blight affects the kernel in a variety of ways that

permit the scabby kernels to be removed from good quality

wheat. The kernels may be deformed enough that they

can be removed by screening. The kernels typically have a

Wheat Cleaning Examples

Test Weight

Wheat Sample (lb/bu) DON (ppm)

Whole Field Sample 54.2 7.0

Light Portion 55.7 5.0

Medium Portion 58.4 3.1

Heavy Portion 59.9 1.5

Screenings 41.2 26.1

Original Cleaned

Factors sample Clean-out Sample

Bushels 1,000 110 890

Test Weight
(lbs/bu) 59-61 57 61-63

Damage 2-5% Unchecked <0.5%

DON level 8 ppm Unchecked 0-2 ppm

Market Price $1.70 $1.00 $3.20

Value $1,700 $110 $2,848

Increase in income from cleaning this 1,000 bushels of wheat was

$858; $110 value of clean out + $2,848 value of cleaned sample -

$400 cost of cleaning - $1,700 value of unclean sample. Cleaning

cost in this example was $0.40/bushel.

lighter test weight, so the very light kernels can be removed

by airflow. If screening and aspiration do not adequately

remove the scabby grain, the wheat can be sorted by

density with a gravity table or fluidized bed separation.

The amount of scabby grain and the amount of wheat

lost during cleaning is different for each lot of grain,

so a small quantity needs to be cleaned to determine the

economics. The cost of cleaning will typically be about

40 cents per bushel. DON can occur on kernels of normal

appearance and shriveled or tombstone kernels. Therefore,

it is not always possible to reduce the DON level by

cleaning the grain.

Is respiratory protection needed while handling

infested grain?

All mold spores, not only those of the Fusarium fungus,

may cause allergic reactions and breathing problems if

inhaled. Appropriate personal protective gear, such as

masks designed to keep out mold spores and grain dust,

are recommended when handling grain. Generally, these

masks are either N95 rated masks, which typically have two

straps, or respirators with HEPA filters. Masks are available

at most hardware stores for about $2.50 each.

STORAGE

Does DON increase in storage?

After the grain dries below a moisture level of about

22 percent, fungal growth and DON production stops.

Anytime the kernel is damaged, however, the potential for

grain deterioration during storage increases. Damaged

wheat should be stored at or below 12 percent moisture

content. Studies show that the allowable storage time for

scabby wheat is slightly less than for non-affected wheat.

Therefore, recommended airflow rates to dry scabby wheat

should be slightly increased above the rates recommended

for good quality wheat. Affected wheat should be cooled

by aeration soon after being placed in storage and further

cooled periodically as outdoor temperatures decline until

the wheat is about 25 F.

MARKETING

What is the best strategy for marketing wheat with DON?

The most cost effective way to market wheat with high

DON levels depends on many factors, such as how much

DON is in the wheat and the current discounts; ability

and cost to segregate, clean and/or blend the wheat; cost

of storage; contract obligations with the elevators; the loan

deficiency payment (LDP); and the price outlook.

Elevator discounts generally are the most severe at

harvest. Discounts usually decrease after harvest, as the

marketing system is able to assimilate the lower quality

grain over time. Market reaction to DON levels can vary

depending on which market elevators are selling into,

how much of their local draw area was affected and the

availability of blending stocks. Elevators and grain exporters

risk outright rejection of shipments that exceed contract

specifications.

At harvest, every attempt should be made to segregate

and store on-farm DON-affected and nonaffected wheat.

The possibility of deferring contracted wheat in the hope

that discounts will lessen with time should be explored. Onfarm

storage also gives the producer time to improve quality

before delivery by cleaning and/or blending. To be worthwhile,

the combined value of the cleanout and clean grain,

less cleaning costs, must be greater than the value of the

original grain. The value of cleanout varies at elevators. A

one-time in/out charge of about 8.5 cents per bushel is an

additional storage cost that also should be considered.

A CCC loan on wheat being stored may offer benefits.

Most importantly, it provides cash flow. It also may have

a lower interest charge than a commercial loan. However,

any LDP that might be available cannot be taken if a CCC

loan is taken. Forfeiture on the loan usually is not the best

alternative since the discounts on forfeited wheat would

be 50 cents for 2.1 to 3 ppm, 75 cents for 3.1 to 4 ppm and

$1 for 4.1 to 5 ppm. Wheat more than 5 ppm would have a

settlement value of zero.

For wheat in the bin, the cost of good quality on-farm

storage is about 1.5 to 2.1 cents per month, based on

interest rates of 4.5 to 7 percent, respectively. Storage into

April/May could be profitable if distant futures prices are

at least 12 to 15 cents higher and remain there, the basis

does not deteriorate, and DON discounts are reduced or

quality can be improved.

FEEDING

Can DON contaminated grain be used as a livestock feed?

In most cases, wheat containing DON can be used as a

livestock feed. However, there are some classes of livestock

that do not tolerate DON well.

Beef Cattle:
FDA limits for cattle are similar to poultry

(dietary levels of 5 ppm). Research conducted in North

Dakota and Minnesota has suggested growing and finishing

cattle can tolerate higher levels (up to 18 ppm based on

research at the Carrington Research Extension Center).

Dairy Cattle:
FDA limits the level to 2 ppm DON in the

diets of lactating dairy cows.

Swine:
Do not feed wheat containing DON to gestating

or lactating sows or pigs weighing less than 50 pounds.

Growing and finishing pigs may be fed grains containing

DON, provided the level of DON in the diet does not exceed

1 ppm.

Poultry:
Poultry can be fed grain containing DON. Total

dietary levels should not exceed 5 ppm (e.g., 10 ppm DON

in wheat could be fed at 50 percent of the diet).

Horses:
No research data exists that has evaluated

feeding grain containing DON to horses. Since monogastric

animals tend to be more sensitive than ruminants to these

type of toxins, horse owners should be extremely cautious

about feeding DON containing grain to horses.

Recommendations for feeding wheat

In addition to the problems related to DON, feed wheat is

a grain that requires diligent feeding management to be

successfully included in a ration for cattle. Wheat ferments

very rapidly, making it a difficult to feed at high levels. Here

are a few pointers for making the most of this grain:

• Wheat is higher in protein and similar in energy to

corn (see following table).

• Limit wheat to 40 percent or less of the ration in

backgrounding and finishing diets.

• Limit durum to 30 percent or less of the ration in

backgrounding and finishing diets.

• Gradually adapt cattle to wheat-based diets. Start

with low levels (10 to 15 percent) and then gradually

increasing the wheat level up to 30 percent (durum)

or 40 percent (hard wheats).

• Wheat should be coarsely rolled or cracked, but not

finely ground for optimum performance.

• Wheat should not be fed in self feeders.

For more detailed information on grain feeding, check

out the following web sites:

• www.ext.nodak.edu/extpubs/ansci/beef/as1184w.htm

• www.ext.nodak.edu/extpubs/ansci/livestoc/as647w.htm

• www.extension.iastate.edu/Publications/PM1994.pdf

Nutrient content of various feed grains
(NRC, 1996)a

Wheat Barley Corn Oats Sorghum

TDN (%) 88 88 90 77 82

NEm (Mcal/kg) 2.18 2.06 2.24 1.85 2.00

NEg (Mcal/kg) 1.50 1.40 1.55 1.22 1.35

CP (%) 14.2 13.2 9.8 13.6 12.6

a
Nutrient analysis can vary. A laboratory analysis is recommended.

What can I do to prevent DON

in the future?

The environment plays a critical role in the development of

FHB and the production of DON. Humid and warm conditions

during flowering favor FHB and DON production. When

environmental conditions are ideal, multiple control practices

are needed to control this pernicious disease.

Crop rotation
will not eliminate Fusarium head blight and

DON accumulation, but will help reduce the severity, even in

epidemic years. Research studies in other states show that

infections have been 5 to10 times higher when corn was

the previous crop than when wheat was the previous crop.

In 2005, a research study in Fargo showed that the field

severity of FHB was 2 times higher with wheat planted into

wheat stubble than when the same variety was planted the

same day in an adjacent field of soybean stubble.

Variety resistance:
No wheat varieties are totally

resistant to Fusarium head blight, but some varieties show

more tolerance to the disease and DON accumulation.

Of varieties currently available, Glenn, Alsen and Freyr

are among the most tolerant. For additional details go to

www.cc.ndsu.nodak.edu/instruct/stack/FHB/FHB.html.

Planting at least two or three tolerant wheat varieties with

differing maturity dates will help minimize the risk of scab

infection. In a wet year, large quantities of the fungus that

causes scab are produced, subjecting virtually any wheat

field to some degree of Fusarium infection. Check variety

trial results from experimental plots to see which varieties

perform best in the presence of the disease.

Fungicides
can help reduce Fusarium head blight and

DON levels by 50 percent to 70 percent in North Dakota

in most years, when using the best available fungicides

and appropriate application timings. Success is greatest

when fungicides are applied to moderately susceptible to

moderately resistant spring wheat varieties. Under severe

epidemics, fungicides have not sufficiently reduced disease

or DON levels to achieve a top market grade in barley or in

very susceptible wheat and durum cultivars. For additional

information on the use of fungicides to control FHB, go to

www.ext.nodak.edu/extpubs/ageng/machine/ae1148w.htm.

Seed treatments before planting may improve seed

germination and seed vigor, but they will not prevent FHB

infection or DON accumulation.

Tillage
buries disease-carrying debris, allowing for

microbial degradation of the Fusarium fungus and lowering

the chance of fungal spore dispersal. Moldboard plowing

is more successful at burying residue than chisel plowing.

However, other factors such as soil or water erosion are

important considerations for tillage practices and residue

concerns may be more effectively dealt with by crop rotation.
http://scabusa.org/pdfs/forum_01_proc_fstu.pdf


Introduction

Deoxynivalenol (DON) is a toxin produced

by fusarium fungi. DON occurs in barley and

other feed grains when grown under certain

climatic conditions. The quality of beer can

be adversely affected when malting barley with

significant concentrations of DON are used.

Illnesses have been observed in livestock that

have consumed feed grains containing high

levels of DON concentrations. As a consequence,

wheat and barley lots often receive

price discounts when DON concentrations

exceed certain levels.

Levels of DON are typically measured in the

marketing channels with commercially available

test kits. Test kits typically are based on

enzyme linked immunosorbent assay (ELISA)

technology. DON measurements are often

made on each lot delivered to the market by

producers. Due to the significant economic

consequences, the accuracy and precision of

DON measurements is of great concern. This

document covers the testing procedures used

by the Grain Inspection, Packers and Stockyards

Administration (GIPSA) of the U.S. Department

of Agriculture.

Backgound

Fungi are probably one of the most numerous

plant families on earth. By definition they are

plants that contain no chlorophyll (can grow

in conditions of little or no natural light) and

range from single cells to a body of branched

hyphae (tubular filaments) that often produce

fruiting bodies that form molds, mushrooms,

smuts and yeasts. Instead of producing their

own food, fungi absorb nutrients from either

a living or dead host material. Mycotoxins

are metabolites (by-products) of the growth

of the molds.

Fusarium graminearum
is the parent fungi of

DON. Wheat and barley are the most commonly

effected grain crops but the same fungus

does infect corn. In the field, it shows up

as a brown discoloration at the base of barley

glumes, a pink to reddish mold on the glumes

and kernels of the wheat heads and the tips of

the ears of corn. Spores of the fungi can stay

dormant on infected residues left on or in the

soil.

The optimal temperature range for the DON

mold is 70 to 85 F with moisture levels preferred

to be greater than 20 percent. This particular

fungi has two distinct growth cycles,

with the mold growing during the warm temperatures

of daytime, while the toxins are produced

during the cooler temperatures of the

night.

Sampling

The first step in DON analysis is obtaining a

representative portion. Great care should be

taken when sampling, since sampling error can

be a significant source of variation.

Testing Trucklots of Barley and Wheat

for Deoxynivalenol (DON)

Page 2

Obtaining a representative sample from a lot

of grain is an important and essential part of

mycotoxin analysis. If the sample is not representative,

the analysis result will not represent

the true quality of the lot. In order for a

sample to be considered representative, it must

be:

1. Obtained with equipment/procedures

designed to obtain sample from all areas

of the lot;

2. Of appropriate size;

3. Adequately identified;

4. Handled in such a way as to maintain

representativeness.

Sampling Methods.
A 1998 GIPSA study

of ten trucklots of DON contaminated barley

found evidence that some stratification of

DON may occur. The lots in the study were

from the 1997 harvest that were stored in

farmer’s bins over the winter. Some blending

of the barley is likely to occur as the barley is

moved from the field to farm storage and then

to commercial elevator. Stratification may be

more pronounced in lots coming directly from

the field at harvest. Truck lots may be stratified

in varying degrees depending on the nonuniformity

in the field and harvesting practices.

To ensure that the sample that is tested is accurate,

proper sampling techniques must be

used to obtain a representative sample. A “coffee

can” sample from the exposed layer of

grain in a hopper car or truck, or a “bucket”

sample as a truck or railcar is unloaded does

not give a representative sample of the lot as a

whole.

A large percentage of grain, as it travels from

the farm to the final consumer, is sampled with

a probe sometimes referred to as a trier. The

probe is the only sampling method approved

by GIPSA for stationary lots. If probe sampling

is performed correctly, the samples

drawn are considered representative.

Hand probes are constructed of brass or aluminum

and come in various sizes with standard

lengths of 5, 6, 8, 10, and 12 feet. The

type of carrier and depth of grain dictates

which probe length is used. For flatbed trucks

or trailers use a 5 or 6 foot probe. For hopper

bottom trailers 6, 8, or 10 foot probes are recommended.

Probe-type mechanical sampling systems

have replaced hand probes at many facilities.

GIPSA has approved two designs (gravity-fill

and core) for probe-type mechanical samplers.

In-load suction probes (air probe) are not approved

because they draw air through the

grain and vacuum excessive amounts of fine

material into the sample.

Figure 1. Grain probe or trier

Air Probe

Not approved

Gravity-Fill

Probe Core Probe

Sample Air

Figure 2. Mechanical Probe Designs

Page 3

Sampling patterns.
How the sample is obtained

with the probe will also affect the accuracy

of results. A study conducted by

Michigan State University found that the variability

of DON measurements in trucks of

newly harvested soft red winter wheat was significantly

higher if less than four probes were

taken from the lot.

GIPSA has established a sampling pattern for

each type of carrier. The sampling patterns

are designed to obtain a representative sample

of approximately 2000-2500 grams which is

more than adequate for DON analyisis.

The following diagrams indicate the standard

sampling patterns. Insert the probe at the

points marked, with the tip of the probe angled

ten degrees in the direction of the arrow.

When two arrows are shown, the tip of the

probe may be pointed in either of the indicated

directions at the sampler’s discretion.

Sample Preparation

The ground portion size required by GIPSA

for barley and wheat is approximately 100

grams. A 1998 GIPSA study of DON contaminated

barley has shown that increasing the

size of the portion ground does not appear to

significantly decrease the variability of DON

results in barley. This does not mean that

sample size is unimportant for DON analysis.

As sample size is decreased below 100 grams,

at some undetermined point, size would become

a significant factor.

Clean the sample to remove dockage using a

Carter dockage tester. The Carter dockage

tester uses aspiration (air) and a combination

of riddles and sieves to remove readily separable

foreign material.

Figure 3. Seven probe pattern for flat-bottom

trucks or trailers containing grain more than four

feet deep.

Figure 4. Nine probe pattern for flat-bottom trucks

or trailers containing grain less than four feet deep.

Figure 5. Four probe pattern for hopper bottom

trailers or containers.

Photo 1. Carter dockage tester