Fumonisin is a mycotoxin that is caused by the fusarium fungus. I will not go into much detail on the fungus itself except to say that it is in the soil and has been around for a long time. The key problem this year is the weather during the summer that caused it to really be a problem for corn in the High Plains. According to the pathologists, the dry, hot period at tassel followed by the cool, wet period in grain fill is the perfect combination of weather to produce a lot of infected corn.
While this is a corn problem, I wanted to quickly address the questions that have come up about fusarium in sorghum and the probability of a fumonisin outbreak. The following is from an email from Dr. Brent Bean, Sorghum Checkoff Director of Agronomy:
I had a good conversation with Gary Odvody this morning. He does not believe there should be
any issues with sorghum. The conditions in a sorghum head are just a lot different than in an upright corn ear. We would need to have wet conditions that lead to general weathering issues in sorghum for there to even possibly be an issue. There are many fungi that compete in a sorghum head under wet conditions. These competing fungi should limit any proliferation of the fusarium species that causes fumonisin. Gary said there is always an abundance of fusarium in the soil. Any additional fusarium left in the field from infected corn would not be significant. So, there should be no increased risk next year from any sorghum planted behind infected corn. [Dr. Gary Odvody is a plant pathologist at the Corpus Christi Extension Center.]
This response from Dr. Gary Odvody was echoed by Dr. Tom Isakeit (TAMU) at the Dumas meeting and Dr. John Damicone (OSU) at the Guymon meeting. Drs. Isakeit and Damicone both answered questions at the meetings about grazing stalks from corn fields infected with fusarium and that is not a problem. I have heard no one mention that any sorghum has been tested for fumonisin at this time.
The worst of the fumonisin seems to be in a triangle from Dimmitt to Hart to Olton. That area harvested first and there were some loads already over 100 ppm and that was before the last 10 days of rainy, cool weather. Currently, feedyards are staying with the 60 ppm level for rejection, but I have heard of one yard that is moving to 30 ppm. The ethanol plants will not take it over 5 ppm since they triple the concentration in the DGS that they market, mainly to dairies.
As for the different levels that different species can tolerate, please see the following references:
https://tvmdl.tamu.edu/wp-content/uploads/2015/01/ED-Fumonisin-Facts-0917.pdf
and
http://www.merckvetmanual.com/toxicology/mycotoxicoses/fumonisin-toxicosis
Dr. Kim McCuistion, Sorghum Checkoff Animal Nutrition Director, supplied me these links and I am much appreciative.
While the discount schedules vary between elevators, the most common discount seems to be $1.00/bu for corn over 60 ppm and $2.00/bu for corn over 100 ppm. However, it has become clear that elevators south of Amarillo may not take any corn over 100 ppm if they feel they cannot blend it off. The great unknown is the effect of the rainly, cool weather we are experiencing at this time. If the corn that was at 50-80 ppm is now all at 120 ppm or greater, then there is a lot of corn that may not be harvested.
Crop insurance enters the picture on fumonisin as a quality adjustment. According to the Loss Adjustment Manual (LAM), corn from 3.1-100 ppm qualifies for a discount. Matt Mitchell with RMA out of Kansas City said the actual value was 2.1 ppm during the meeting at Dumas, but I have not been able to confirm that and RMA has yet to put out a statement to that effect. Given that, I am staying with the 3.1 ppm value since that is currently in the LAM.
Corn that is over 100 ppm falls into a different category for crop insurance purposes. Currently, the official fumonisin tests can only register up to 60 ppm. So while the 100 ppm number exists, the reality comes from when the elevators decide they will not take any corn over 100 ppm and the corn becomes unmerchantable. Let me clarify the confusion over the “official” fumonisin tests and what actually shows up on a meter when the test is run. The “official” standard up to 60 ppm is where they have control sets to run against the meter and verify its accuracy. The meter can measure more than 60 ppm, but it does not have an approved control for testing. According to the Texas state chemist, they are working on certifying tests at 100 ppm, but that has not yet happened.
From a crop insurance loss standpoint, unmerchantable grain has a zero market value (ZMV) and it would result in zero bushels from that unit and the farmer would be eligible for a complete loss. I hope this does not happen. Since the official tests today only go to 60 ppm, an elevator can still dump grain over 100 ppm and the grain can still be adjusted and claims closed without grain having to be sold, fed, or destroyed.
If the corn is between 3.1 and 100 ppm, then the default discount factor (DF) is 0.500. This means that the number of bushels produced on a unit would be reduced by 50% (cut in half) and those bushels would be used to compute an indemnity. To receive the default discount factor, the grain must be unsold (in open storage or in farm storage, which includes grain bags) when the claim is closed. If the grain has been sold already, then the discount factor is based on the reduction in value (RIV) that was received by the farmer when his corn was discounted at the elevator. For farmers with contracted corn, the key on the default discount is to have the elevator show the corn as open storage until the claim is closed and then roll that corn against the contract the next day.
Given that the current discounts only begin at 60 ppm, the RIV would be zero (no discount) if the grain was sold before the claim was closed even if the corn tested 20 ppm. The indemnity can add up very quickly when only counting half of the bushels in the production. The downside to this is production used to settle the claim (half the bushels) will be on the APH (Approved Production History) for 10 years. But as one farmer told me, “one in the hand is better than two in the nest.”
Given the current weather, I am assuming that most corn in the Texas and Oklahoma Panhandles and maybe even into SW Kansas will have fumonisin and will test over 3.1 ppm. If that is the case, then claims must be opened before harvest and farmers must visit with adjusters. Even if some of the corn is already cut, I have seen examples where with even half the corn already cut, the indemnity could still be over $100/acre when taking the expected indemnity over the entire acreage. For those farmers with very high APHs, high coverage levels, and no corn harvested (so
it would all qualify for the 0.500 DF), this number could be over $350/acre.
Based on these large numbers, I am also assuming that RMA will have a standard fumonisin table in the quality adjustments for 2018 that steps the default discount up from 3.1 to 100 ppm so that corn at 10 ppm is not getting the same discount as corn at 70 ppm. This does exist today in the quality adjustments for aflatoxin but not fumonisin.
Currently, the Amarillo and Plainview Grain Exchanges can produce official certificates for fumonisin testing as well as Dumas Coop. Servi-Tech Labs in Amarillo is very close to certification and hopes to have that in place next week. An official certificate is what is required for crop insurance purposes.
Please follow this link for the 2017 Loss Adjustment Manual (LAM). The key paragraph is 1109 which begins on page 267 of the PDF in regards to fumonisin:
https://www.rma.usda.gov/handbooks/25000/2017/17_25010.pdf
An example Special Provisions of Insuance (SPOI) is linked here. The quality adjustment section begins on page 7 and will be the same for all counties in the High Plains area.