Post

Scout and be ready to act

It seems a little unfair that so many have to suffer the destruction of a hurricane for us to enjoy the benefits of much needed rainfall in a drought stricken Midwest. Hurricane Dennis may or may not be bringing another unwelcome visitor to our soybean fields: Asian soybean rust.

I asked Growmark Agronomist Kevin Black if Illinois farmers are ready, if indeed the dreaded fungus shows up here.

“I think we’re just about as ready as we can be for soybean rust, with the exception that there still seems to be a huge knowledge gap on this disease because we have no personal experience with it in the Midwest,” said Black.

The problem says Black, is that there are some folks who are absolutely convinced that soybean rust spores will be riding the storm system into the Midwest, and that they must get out and spray with fungicides. “The truth is,” said Black, “Dennis may have brought some spores, but we don’t know for sure. And there’s another thing going on out there. If Dennis indeed did bring spores, it is at a fairly low level. So, it is quite possible that somebody in the southern part of the Midwest or even up into Illinois or Indiana may get soybean rust. We don’t know, and it’s that lack of knowledge that really creates so much difficulty for us.”

Although there may be rust spores found, if those rust spores are not found on soybean plants, there is no soybean rust problem. I know that might sound confusing, but the best analogy I have heard comes from a farm broadcaster on my staff. He said, “It’s sort of like the AIDS virus. If they find it on your skin, you don’t have AIDS. If they find it in your bloodstream, you do.”

Experts are using a trapping system to find spores from the fungus as they move through the atmosphere. The plan was developed by watching how rust is battled in other countries around the world. Marty Wigglesworth with Syngenta told Brownfield that in Paraguay, this simple trap has given farmers a 7 to 10 day “heads up” on where soybean rust spores have been located. Wigglesworth stresses that just because the spores have been found in the atmosphere does not mean the fields are infected with active rust. Finding soybean rust spores in traps is a signal to growers to scout like crazy.

These traps remind me of a 7th grade science project. Vaseline is spread inside a series of elevated slides, so the air must pass through them. The slides are then sent to a lab, in the case of Syngenta’s research, The University of Arkansas Plant Pathology is used. At the University, the scientists go to work to determine if there are spores and how many.

Last week, rust spores were found in spore traps in both Kentucky and Tennessee. Kevin Black told me, “The spores appeared to look very much like rust spores, but they were never absolutely confirmed. It was also pointed out very clearly that there were no infections in those fields. This was a trapping of the spores themselves. It is very important to note that pathologists in these areas were advising farmers that this is not a good basis to spray.” Black said, “Their advice is to wait and see if and where infections pop up before we decide to spray.”

Vigilance in scouting is the advice I hear most often from agronomists. Black said it is important to acknowledge there is a risk factor at work right now. Black said, “We believe the best recommendation to farmers right now is to have a very, very high level of awareness without a high level of panic.”

If you would like to learn more about Asian soybean rust, go to www.brownfieldagnews.com/soybeanrust. You’ll find a number of stories we’ve done on rust and several links to other rust-specific websites.

Scout and be ready to act.