Posts Tagged ‘barley’

Small Grain Disease Prevention

Friday, September 23rd, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Be sure that you plant wheat and barley varieties with high levels of disease resistance. Select varieties with high levels of resistance to powdery mildew, leaf rust and stripe rust. Seed should be treated with Baytan, Raxil, Dividend or other labeled product to protect plants from loose smut and common bunt. Varieties that are susceptible to powdery mildew should be treated with Baytan, Dividend, or other seed treatment fungicide that will protect them from early infection.

Small Grain Herbicides

Friday, September 9th, 2011

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

For the past two weeks I have written about weed control for winter wheat. The concepts and ideas I talked about are the same for barley and other winter grains. The following table is a list of herbicides labeled for the various small grains.

 

Herbicide Form. Active Ingredient MOA /

Grp #

Winter Wheat

Barley

Oats

Rye

   

Broadleaf Weeds

 

 

 

Harmony SG 50 SG Thifensulfuron 2

XX

XX

XX

 

Unity 75 DF Thifensulfuron 2

XX

XX

XX

 

Harmony Extra 50 SG thifensulfuron +

tribenuron

2 + 2

XX

XX

XX

 

TNT Broadleaf 75 DF thifensulfuron +

tribenuron

2 + 2

XX

XX

XX

 

Starane Ultra 2.8 L Fluroxypyr 4

XX

XX

XX

 

2,4-D various 2,4-D 4

XX

XX

XX

XX

dicamba (Banvel) 4 S Dicamba 4

XX

XX

XX

XX

Finesse 75 DF chlorsulfuron +

metsulfuron

2 + 2

XX

POST only

 

 

   

Numerous Grasses / Broadleaves

 

 

 

Osprey 4.5 WG Mesosulfuron** 2

XX

 

 

 

Axiom 68 DF flufenacet + metribuzin 15 + 5

XX

 

 

 

PowerFlex 7.5 WG Pyroxsulam 2

XX

 

 

 

   

Strictly Ryegrass

 

 

 

Hoelon 3 EC Diclofop 1

XX

XX

 

 

Axial XL 0.42 L Penoxaden** 1

XX

XX

 

 

   

Seldom Recommended

 

 

 

Peak 57 WDG prosulfuron 2

XX

XX

XX

 

Stinger 3 L clopyralid 4

XX

XX

XX

 

Buctril 4 EC bromoxynil 6

XX

XX

XX

 

Aim 2 EC carfentrazone 14

XX

XX

XX

 

Prowl H2O 3.8 ACS pendimethalin 3

XX

 

 

 

Maverick 75 WG sulfosulfuron 2

XX

 

 

 

*Finesse is labeled in barley for postemergence applications only
**Also contains a safener

Related Articles:
Considerations for Weed Control in Winter Wheat I
Considerations for Weed Control in Winter Wheat II
Metribuzin Use in Winter Wheat

Head Scab and the Relationship to Saved Seed and Vomitoxin Production

Friday, June 10th, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Head scab has been observed in barley and wheat this season in varying amounts. Barley is just now arriving at the grain elevators. The amount of scab that occurs is dependent on the flowering time, the presence of the scab spores that infect the heads during flowering and the weather conditions during flowering. Most of the barley and wheat varieties that we grow have little or no resistance to head scab. The fungus can be present on old corn stover, and residues of old barley and wheat crops. What drives this disease is wet, warm weather during the flowering period. If the heads of barley or wheat are infected with the fungus (Fusarium graminearum) that cause head scab, that fungus can produce several toxins that can contaminate the grain. These toxins are often referred to as vomitoxins because they can cause feed refusal in non-ruminant animals. The most common vomitoxin that is produced by the head scab fungus is deoxynivalenol or DON for short. DON production by the fungus is extremely variable depending on environmental conditions. The presence of scab on the grain does not mean that the grain has to have DON nor does high or low levels of scab relate to the amount of DON present. A high level of scabby kernels in the harvested grain means that DON will likely be present.

What about the saving or using seed from scab infected fields? As much scabby wheat kernels as possible should be removed from good seed during combining and seed cleaning. This is not easily done with barley or may not be possible because barley does not get as light as wheat. Saved seed kernels can be infected with Fusarium, and seed treatments can reduce the effects of Fusarium on seed. Fusarium on seed can cause a seedling blight of barley and wheat but the seedling infections do not result in head scab or DON in fields that might be planted with infected seed. In fact some studies have shown a reduction of scab infections in seed during storage. Low levels of scab infected wheat or barley can be saved for seed if properly handled and treated without any risk of scab occurring in the crop from that seed.

Another issue for barley producers is that the threshold levels of DON in wheat may not be the same compared to barley presuming that the barley is not intended for human consumption. The DON threshold for wheat is 1 ppm because of human consumption concerns. Barley for feed can have up to 10 ppm without harmful effects depending on the animals being fed and the proportion of infected grain being fed. In my opinion barley should not be held to the same threshold as wheat depending on its destination or final use. See the following information on DON levels in food and feed.

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.

Taken from NDSU Fact sheet PP-1302, DON (Vomitoxin) in Wheat. http://www.ag.ndsu.edu/pubs/plantsci/pests/pp1302.pdf

 

Harvest Aids for Small Grains

Friday, June 3rd, 2011

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

A number of glyphosate products such as Roundup and Touchdown are labeled as harvest aids in winter wheat and barley. Check the label for other formulations of glyphosate. Applications must be made after the hard-dough stage and at least 7 days prior to harvest. Aim is labeled as well, but the spectrum of control is limited to velvetleaf, morningglory, pigweeds, and few other weeds. Apply at least 3 days before harvest. Use of 2,4-D (or products containing 2,4-D) is generally not recommended as a harvest aid due to its volatility, and potential damage to the crop during application.

 

Agronomic Crop Disease Updates

Friday, June 3rd, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Soybeans
The dry conditions combined with high soybean cyst nematode (SCN) egg counts could mean we will see more stunting from SCN this season. Be on the lookout for stunting in irregular areas. The SCN females can be seen on the roots of infected soybeans around 28-32 days after planting.

Barley
Barley harvest is fast approaching and the crop looks pretty good. Besides some leaf rust, net blotch, powdery mildew on ‘Thoroughbred’, and a little head scab, diseases have not been bad this season.

Wheat
A few diseases were observed during a recent check of the variety plots near Middletown in New Castle County. Low levels of tan spot and powdery mildew were seen in a few varieties, but all but one of the 45 entries had some head scab. Most of the infections were under 1% of the heads infected and many of those heads were only partially infected. Wheat in NCC was the most at risk according to the scab predictions. Some shriveled grain with the white coating of the Fusarium fungus was observed on some of the infected heads. Increasing fan speed on the combine will blow the light chaffy “tombstones” out the back and not contaminate the rest. Planting multiple wheat varieties with different flowering times (maturity) will decrease the risk of scab for next year. Statewide, overall scab levels are low compared to several years ago. I had mentioned in last week’s WCU that several varieties in the variety trial had genetic flecking or a resistance reaction including Merl, USG 3209, USG 3251, USG3665, Sunburst, and Grow Mark FS627. These symptoms are not an active disease.

Flecking on USG3409 that looks like a disease

Head scab on wheat

Healthy kernels and Fusarium head scab infected “tombstones”

Tan spot on wheat

 

Harvesting Grain from Scabby Fields
The following are tips to reduce the amount of scabby kernels in the harvested grain and to avoid potential health problems for combine operators and grain handlers. Scabby grain is contaminated with mycotoxins, especially vomitoxin, which is harmful to humans.

Harvest tips:
1. Avoid breathing in dust from scabby fields by using a high quality dust mask. Spores of the scab fungus (Fusarium graminearum) and small pieces of contaminated plant parts are present in the dust. Inhaling these particles may cause health problems.

2. Harvest the most severely scab damaged areas, such as low areas or double seeded headlands, separately. Don’t co-mingle the most damaged grain with sounder grain.

3. Turn up the air on the combine to blow out the lightest, scabby kernels back into the field.

4. If rain is forecast, it may be better to harvest scabby fields at slightly higher moisture content than to wait for grain to dry down. However, this grain still needs to be dried down and maintained below 15% moisture after harvest to prevent fungal growth in storage.

5. After harvest, gravity table grain separation can be used in removing more of the light-weight, scabby kernels.

6. Get grain from scabby fields tested for vomitoxin before feeding, before blending, or before making a decision to discard suspect grain.

From http://www.scabsmart.org/harvest%20practices.html

 

Small Grain Disease Update – May 27, 2011

Friday, May 27th, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Barley
The most prevalent diseases that can still be seen in areas where the barley has not returned yet are the spot blotch form of net blotch and powdery mildew. After checking the barley varieties today near Sandtown in western Kent County I don’t believe that net blotch will be affecting yields, but powdery mildew on unsprayed ‘Thoroughbred’ will reduce yields if the flag leaf is infected. There is some scab infected barley in Kent County.

Wheat
The wheat in the Kent County variety trial has tan spot moving in rapidly on some varieties. Most of the varieties are in the watery ripe stage of development and will not likely be adversely affected. Leaf rust was easily seen on a public variety ‘Rumor’. Powdery mildew in general was low in most varieties but was in the upper canopy on SS8302, Milton, Bravo, and USG3770. There is a low level of scab in the trial as well. If scab is going to appear it should be evident now or very soon depending on location. Low levels of scab (less than 1% of the heads infected and most of the infected heads were only partially infected) were present in 8 out of 45 varieties (around 18%).There is some sort of physiological spotting that could look like a disease but is probably a resistance reaction by the variety in response to a fungal infection. This spotting was evident on the following varieties at this Sandtown location: Merl, Sunburst,USG3665, USG3409, USG3251, and Grow Mark FS627.

 

Small Grain Disease Update – May 20, 2011

Friday, May 20th, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Fusarium Head Blight (Scab) in Wheat Update: Although the recent weather pattern early this week has been favorable for head scab in wheat, most of the wheat in Sussex and Kent County has completed flowering by now and not likely to become infected with scab. If you have wheat that is flowering now consider a fungicide application of Caramba or Prosaro. Wheat that is about 5 days or more past initial flowering cannot be treated. The labels state the last stage of application is mid-flower and there is a 30-day to harvest restriction.

Scab identified on barley. We just received a sample of ‘Nomini’ barley from Kent County and have confirmed a scab (Fusarium head blight) infection on the top 6-7 kernels. The sample was only two heads and several plants but growers will want to keep an eye out for bleached heads on barley from here on out. Nothing can be done now but increasing fan speed on the combine at harvest which can help blow the lighter chaffy infected grains out of the combine. Hopefully this turns out to be an isolated find.

 

Agronomic Crop Disease Update – May 13, 2011

Thursday, May 12th, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Barley
Powdery mildew on ‘Thoroughbred’ is the most common disease at the present time. Fields with the top two leaves with mildew will have some yield reduction. After looking at the variety trials in Sussex County on Tuesday I could also find small amounts of leaf rust, barley scald and the spot form of net blotch. None of these should impact yield.

Wheat
Wheat is looking very good at the present time. There is very little disease present. A few unsprayed varieties have some powdery mildew that is confined to the lower leaves and leaf sheaths. A small amount of leaf rust was also spotted on one unsprayed variety on the lower leaves. Most of the wheat that I saw has flowered and with the dry weather in most of the southern parts of the state, it looks like head scab should not be a problem. In the northern areas of the state if we get showers this weekend we may have some opportunity for infection if wheat is flowering.

Barley scald

Soybeans and Soybean Cyst Nematode
It is still not too late to check for soybean cyst nematode especially if susceptible soybeans are going to be planted. Soil test bags with the submission form can be purchased at the Extension offices. If you need results quickly, test results can be sent via FAX or email if you provide the number or email address on the Nematode Assay Information Sheet. This information sheet can be found on the web at the Plant Clinic Website http://ag.udel.edu/extension/pdc/index.htm .

 

Small Grain Weed Control

Friday, April 22nd, 2011

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

I have looked at a few fields of winter wheat or barley where growers were concerned about lack of weed control. Turns out these fields had jagged chickweed or speedwell in them, which spring applications of Harmony Extra do not control. Based on our observations either Osprey or Harmony Extra applied in the fall did do a good job of controlling jagged chickweed. Speedwells are not controlled with Harmony Extra. We have trials this spring and will have more to share with you by fall, but most of the products that can be sprayed this late in the season do not control speedwell.

For wild garlic control, Harmony Extra is the product of choice and the label allows two applications per season. But, be sure to read the label for the total amount that can be used per season.

Common chickweed

Common chickweed

Jagged chickweed

 

Barley With Multiple Nutrient Deficiencies

Friday, April 22nd, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu and Phillip Sylvester, Kent Co., Ag Agent; phillip@udel.edu

Another field of barley with severe deficiency symptoms showed up in Kent County this past week. Although the field had received ammonium sulfate this spring, the rate used provided only about 10 to 15 lbs of S per acre, which is less than the crop requirement. If the low S fertilization rate is coupled with the heavy rainfall many areas have experienced over the past several weeks, it would not be surprising that a significant amount of the sulfate-S has leached below the rooting zone of barley. In this case, although the visual symptoms (Photo 1 and 2) suggested sulfur (S) deficiency with general chlorosis of the leaves, especially the newest leaves, and shortened plants, the soil test suggested that S was not the only deficiency likely to impact barley yield even if sulfur were added (Table 1). On the bad sample note the low soil organic matter (SOM) level (0.9%) and the impact on the cation exchange capacity (CEC) of the soil (2.1 meq/100 grams of soil in the bad area versus 3.6 meq/100 grams of soil in the good area). The CEC impact was also evident in the amount of potassium (K) and magnesium (Mg) that the soil could hold.

Photo 1. Close-up of deficient barley plants showing general chlorosis, especially in newest leaves, and stunting.

Photo 2. Field view of deficient barley plants showing general chlorosis and stunting compared with less affected plants in the background.

The short term solution to the problem is the addition of K-Mag (0-0-22-11Mg-22S) fertilizer to the field. However, the soil test results suggest that on a longer-term horizon, the critical need of the field is the addition of organic matter, either as green manure crops, compost additions, or manure additions. Trying to maximize the amount of crop residue and minimize the amount of SOM mineralization due to tillage operations is also recommended. The use of winter cover crops and green manure crops whenever the field is not being cropped will gradually raise the SOM levels, as will any additions of manures or composts. Not only with organic will additions help raise the CEC and soil nutrient holding capacity but will also help increase water holding capacity and improve yields in the long run.

Table 1. Soil test report on barley field comparing good and bad areas.

Good Barley Bad Barley
Soil pH 1:1 6 6.3
Buffer pH 6.9 7
Organic Matter % 2.4 0.9
U of D P Sat Ratio 39 59
Mehlich3 Phosphorus ppmP/FIV 193 144
K ppm 98 54
Ca ppm 442 275
Mg ppm 74 44
SO4-S ppm 20 7
Zn ppm 4.56 2.99
Mn ppm 61 15
B ppm 0.36 0.16
CEC meq/100g 3.6 2.1
H* 15 10
K* 7 7
Ca* 61 65
Mg* 17 18
Na* 0 0

*Indicated Base Saturation