By now, corn farmers are well aware that aflatoxin is capable of derailing plans to sell a hard-won crop. In 2011, worries about aflatoxin have certainly not diminished with more U.S. corn acres planted, along with a widening list of drought-struck counties. Also tossed into the mix is an increasingly vigilant set of international trading partners.

For more, see aflatoxin.

So, how best to deal with the potentially deadly fungal disease? Syngenta says its biological product, Afla-Guard, is gaining popularity among farmers wanting to prevent aflatoxin.  

In early April, Delta Farm Press spoke with Dave Ross, Syngenta technical brand manager, about Afla-Guard’s discovery, unique manner of working, and ramped up scrutiny of U.S. grains by importers. Among his comments:

On increased farmer attention…

“We got involved around 2008 when we became interested in the Circle One Global product, Afla-Guard. They’d registered it in peanuts but hadn’t yet registered it in corn.

“At that time, we found that not a lot of growers were admitting they had a problem. But when we talked about the fact there was a solution for aflatoxin, a lot more growers said they had issues.

“In the last several years, we’ve seen more concern about aflatoxin. That could be due to more aflatoxin out there. But it’s also because many more people are paying attention to aflatoxin.

“There’s more scrutiny on food safety, more concerns raised by the public. With blogging and the Internet, information is readily available so a lot more people know – or, at least, think they know – what’s happening.

“So, in the lead-up to 2010, we found increased testing and much more scrutiny of aflatoxin. It is affecting acceptance of crops from growers by elevators, when it hits consolidators and are put on Mississippi river barges and shipped (overseas).”

On importer testing levels…

“Aflatoxin is being tested (overseas) to lower levels than in the United States. Here, we have a 20-parts-per-billion limit on aflatoxin in order to be eligible to go into any human food product and for interstate transport. In Europe the limit is 4-parts-per-billion.

“So, the consolidators are looking for a safety factor. They don’t want rejections of a big load – especially big container ships. They want below 10-parts-per-billion if the crop is staying domestic. It has to be under 4-parts-per-billion if it goes international.

“The elevator is concerned because the aflatoxin-containing corn must be kept from the (clean) corn.”

On Afla-Guard’s development…

“Afla-Guard was developed (with) the NRRL21882 strain of Aspergillis flavus. It was isolated by Joe Dorner at the USDA-ARS peanut lab in Dawson, Georgia. He was doing work on mycotoxins that can get into peanuts.

Aspergillis flavus is one of the primary mycotoxin-producing fungi that attacks peanuts. It’s picked up by the plant when it’s pegging.

“Dorner was looking for strains of A. Flavus that don’t produce aflatoxin. He tested a lot of them before isolating NRRL 21882. He decided to build up the numbers of the strain and put it in the field to try and outcompete the native fungus.

“It was successful and reduced aflatoxin in peanuts by about 85 percent. It’s put on peanuts when rows have lapped, the middles have closed and there’s a bit of shade on the ground.

“After Dorner discovered and developed the strain, a company called Circle One Global – based in Cuthbert, Georgia – wanted to market the product. They developed it, achieved registration and launched it as a peanut crop product in 2004.”

On how Afla-Guard works…

“A strain of A. Flavus – identical to the one that creates aflatoxin, except it is incapable of creating a mycotoxin – is used in Afla-Guard.

“Essentially, it’s a benign form on the fungus. We put it in the field in large enough numbers that it basically overwhelms the native fungus.

“Under normal conditions, if there’s an ecological niche (a wound in a peanut or corn kernel where the fungus can enter) the native fungus will get in. Then, once established, it will create aflatoxin.

“We simply put enough (benign) spores out to get to those wounds first. It fills the ecological niche, the bad fungus can’t get in, and no aflatoxin is produced.

“Growers will still see the fungus on the plants. But they won’t have the aflatoxin. Remember: Aspergillus Flavus is not regulated but aflatoxin is.

On delivery of Afla-Guard…

“The product is delivered on barley grain that has been hulled and de-germed (so it won’t germinate). The barley serves as a carrier and food source. When it picks up moisture off the ground (from dew, irrigation, rainfall, etc.), the fungus begins to grow and disseminates throughout the field.

“It’s a neat concept and product. The grower, walking through the field, can see the barley grains that become green and fuzzy – kind of like moldy bread. The A. flavus strain sends it through the field.

“For corn, Afla-Guard is put out between 10-leaf stage and tassel. We’re trying to achieve and high number of (benign) spores by the time of tasseling and silking.”

On acquiring Afla-Guard…

“Syngenta acquired the product and Circle One Global in 2009. Since, we expanded the registration into corn and adjusted the label to allow a bit wider window and reduce the rate (from 20 to 10 pounds). The label adjustment also allowed for aerial application.

“2010 was the first full launch of Afla-Guard in corn for us. It was a success – we gained understanding as did the growers. Sales have been brisk and we’ve seen big interest from growers. We’re being told, for instance, that there are areas of northeast Texas where you can’t find an untreated acre.”

In marketing this, do you follow drought monitor maps?

“We’ve actually done that and asked if there is some sort of model we can use to predict where the drought problems will be.

“We’ve found you have to be ahead of the curve with this. Once a drought hits, it’s kind of too late. A grower doesn’t want to wait until he gets into a bad situation to use this.

“It really needs to be applied preventatively. Those growers in areas that have a perennial problem with aflatoxin, or drought, need to apply it around V-10, if possible.”

How long is shelf life?

“It’s a biological product, so it’s the year of manufacture. Legally, the product has to be used within four months of purchase.”

Any competition?

“There is a product called AF36 sold as a nonprofit product by the Arizona Cotton Council.

“It works similarly to Afla-Guard, another strain discovered and developed by USDA researchers in Arizona. Specifically, it’s for cotton.

“A lot of people don’t think of cotton when considering aflatoxin. But there can be a problem with aflatoxin in seedcake after oil has been pressed. That goes into animal feed.

“The group recently got registration for that product in Texas. So, it’s only registered in Texas and Arizona for cotton and corn. Afla-Guard is registered in all states for both corn and peanuts.”

For more, see AF36. 

Does Afla-Guard work on cotton?

“We’re testing that. Data shows it works. But it’s been difficult to get trials with high enough levels of aflatoxin in cotton. We need that to give us confidence. But it’s the same principle in cotton as it is in corn and peanuts. Theoretically, it should work in any crop as long as it is applied properly and at the right time.”