Last year, we had more reports of aflatoxin in corn than previous years and with the extreme heat we are experiencing now, folks have concerns once again about managing aflatoxin. Producers who went to winter meetings may remember some UT data shown about an aflatoxin preventative product called AflaGuard marketed by Syngenta. AflaGuard is a nontoxigenic form of Aspergillis that is aerially applied before tassel emergence to outcompete the toxic form of Aspergillis and help reduce aflatoxin levels in corn (we are using a good form of a disease to fight a bad form of the disease). We have one year’s data on this product from work done at Jackson in 2010 (see table below). So, with limited data I can only make a few observations:
- We reduced our aflatoxin levels as long as material was applied prior to tassel (target application is at V10 this year).
- We did not always reduce our aflatoxin level below 20 ppm. We need more data on this product to figure out how consistent the product is from year to year.
- Product cost $13-13.50 per acre plus the cost to aerially apply (approx. $21/acre total)
- Cost prohibits using this material in every field. Consider use in fields that have history of aflatoxin problems first.
- AflaGuard is a disease organism and can cause some ear mold. The mold may fluoresce under a black light like the toxic form of Aspergillis (even if there may be no detectable aflatoxin in your sample). Although many grain handlers have quit relying on black light technology and use an ELISA test to detect aflatoxin, producers should tell their grain handler that AflaGuard has been applied during the season.
| Timing of AflaGuard Application | At-Harvest Aflatoxin Level (ppm) |
| Untreated Check | 79** |
| V9 | 48 |
| V12 | 9 |
| V15 | 32 |
| VT (full tassel) | 131 |
| ** 20 ppm or below is desired level for general use | |
I have dry-land corn and irrigated corn. Which fields would more likely have aflatoxin? Are 110 day varieties more susceptible than 114 day varieties? Do Pioneer varieties experience this more often than Dekalb or Croplan? Any thoughts would be helpful. Many thanks.
Richard,
I’ll take a shot at this and let anyone who cares to disagree. Aflatoxin is clearly associated with drought stress. Thus, irrigated corn is much less likley to have problems with aflatoxin (or respond to Aflargard). Corn maturity or hybrids in themselves are not big factors. However, drought stress just before and during pollination defintely increases the likelihood of aflatoxin. So, earlier or later pollinating corn may be more affected depending on the timing of rainfall events. I’m sure there are some differences in how well some varieties tolerate drought, but I suspect this has much to do with how the timing of pollination matches drought conditions. Hope for rain!
We do not see aflatoxin in TN every year- even in dry years such as 2007. Scott is correct in that dryland fields are more at risk for aflatoxin. Irrigation reduces water stress to the crop and therefore aflatoxin. Dry, hot conditions just prior to and following silking can increase the chances of having aflatoxin as well as field history (droughty soils, poor fertility, non-Bt with insect damage, high levels of aflatoxin found in corn grown previous years). Planting corn in May may improve the chance of aflatoxin because dryland corn is silking under higher heat and usually drier conditions. There are no aflatoxin resistant hybrids (companies are working on these) and not much information on susceptibility. We assume that any hybrid would be susceptible under stressed conditions where disease pathogen is present in abundance. Whether we get it or not depends on the amount of disease present, stress level in the field and weather conditions near tasseling.