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Wheat Ergot Update

Numerous calls have come in on the wheat ergot situation.  It must have been the perfect environmental conditions for this to happen this year in such a wide area and I need to take some time to figure out why this year during conditions that also favored scab and not a few years ago with similar environmental conditions.

Two main questions have been raised:  “Can I save back seed” and “can I bale and graze straw?”.  I don’t recommend that you save back seed, yet many seed fields in the area most likely were affected as well.  Seed can be sifted on a gravity table to help clean it so that is an option-but most farmers don’t have means for doing this so ultimately I wouldn’t recommend our farmers to save back seed.

In regards to baling straw and grazing, while walking harvested fields, I was noticing some ergot in heads that were too short to go through the combine heads.  Ultimately, the few kernels in a large amount of straw would be so dilute, I wouldn’t expect there to be problems with grazing the straw.  If you’re concerned about using wheat straw for feeding or bedding, you can always dilute it with alfalfa or another feed to reduce chances of ergotism in livestock even further.  I should point out that I’m talking about wheat straw in which the wheat grain has been harvested.  I would not recommend feeding wheat straw that was just cut with the ergot contaminated and wheat grain in tact.  If you plan to feed straw in that situation, I’d recommend sending samples to a Vet Diagnostic Center for alkaloid testing.

A third question I’ll throw in here is should you plant 2nd year wheat if that is your rotation.  While it is not assumed that ergot will happen every year and while the chances of ergot happening a second year are not great, it’s best management practices to go ahead and rotate to be on the safe side as any sclerotia (black fungal ergot fruiting bodies) would be lying on the soil surface and can produce spores that could affect the next wheat crop.  Again, this isn’t guaranteed to be a problem again next year (unlike things such as tan spot or septoria that are likely to show up in wheat on wheat fields), but to be on the safe side, I would recommend rotating.  Dr. Stephen Wegulo also wrote an article on ergot in wheat at the following site.

CropUpdate: 7-5-11

Last week was a blur of phone calls but it’s great to receive them and know so many of you are doing your best to wait for your soil to be depleted before scheduling your first irrigation!  There are some of you in the Little Blue NRD who haven’t received the rains the past few weeks and have hit the 90-100 trigger on your watermark sensors to schedule your first irrigation.  Most of you reading this won’t have to irrigate till after tassel (and then you can take into account the 3rd foot in your average)!  The 90-100 trigger relates to 35-40% soil moisture depletion and is proven by research via Dr. Suat Irmak at South Central Ag Lab for our silty clay soils.  Waiting for the trigger, regardless if you’re on load control or not, will still allow you at least a week to 10 days before you have to worry about getting behind.  Please continue to call with questions.  There’s also a discussion topic on my blog for your comments/questions.  

Corn and beans are looking good overall, are closing canopies, and corn is rapidly growing.  Wheat is being combined in the southern tier of counties and there has been quite a range of yields due to the dry weather producing small heads and disease issues such as scab, smut, and ergot.  Scab (Fusarium Head Blight) is a concern when we receive rain and high humidity during and around flowering.  We were recommending fungicides at that time.  Some people escaped it, some put the fungicide on, and others didn’t-so there’s a range of yields out there from that.  Common bunt (stinking smut) is the smut that creates clouds of black spores when you’re combining and the grain smells like fish.  Loose smut is loose in the head and doesn’t form a kernel shape like common bunt does.  Both can be prevented by not saving contaminated seed and using fungicide seed treatments at planting.

Ergot is one I hadn’t seen in wheat since I’ve been here but have in roadside grasses.  Ergot is caused by a fungus that infects the wheat head during cool, wet conditions during flowering.  Like the fungus that causes scab, it simply replaces the normal pollination process and instead, a black/purple hard fruiting body (sclerotia) is eventually formed.  Before this is formed, a sugary drop called honeydew is formed which then turns into the sclerotia.  It’s a problem for our producers because I don’t know that you can set your fans to blow it out like you can for light, scabby kernels since ergot sclerotia are denser.  The problem with ergot is that it contains toxic alkaloids (one is like LSD)…in fact, it’s blamed that ergot-contaminated grain is what caused the Salem Witch Trials.  These alkaloids are also toxic to livestock so contaminated grain should not be fed or even blended off for livestock.  Federal grain standards classify wheat as ergot infested when it contains more than 0.3% sclerotia.  If you are finding ergot-contaminated grain in your fields, do not save seed back next year; start over with disease free certified seed.  The sclerotia will live on top of the soil for a year (they will produce spores next growing season so don’t plant contaminated wheat fields back into wheat, barley, oats, or triticale).  Mowing roadside ditches and keeping wheat fields free of other grasses can help prevent ergot infested grasses from spreading the ergot fungus to wheat via blowing spores and rain splash.  More information can be found by checking out the UNL Extension publications Head, Grain, and Seed quality on the http://cropwatch.unl.edu/web/wheat/disease Web site.

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