Sorghum producers dealing with ergot, or honeydew, problems brought on by cool, humid fall weather should not panic. They just need a little patience.
While it's true there is no fungicidal remedy for ergot, freezing weather will dry it up and a good rain will wash it off the crop, says Jeff Dahlberg, National Sorghum Producers research director.
To date, no ergot has been reported this year in U.S. sorghum, he says, though conditions are right for it to develop. Ergot only attacks immature, unfertilized sorghum during humid weather conditions. That puts late sorghum fields particularly at risk, and 25% of this year's crop falls into that category, says Tim Lust, National Sorghum Producers CEO.
The honey-like residue ergot produces can cause problems with harvesting machinery and trucks, and at elevators.
"If producers walk through fields and see that honeydew, I suggest they wait to harvest until a freeze occurs. Unfortunately, this year there's so much late sorghum, a lot of them are going to have to wait until a freeze, anyway. If it's ready to harvest before that, a rain will wash it off. It's not a complete loss by any means,” Dahlberg says.
"There is no toxicity in this stuff. It will go into the animal food chain and to ethanol plants without a problem. This is a very unique year for growing conditions. Ergot may or may not show up. Sometimes a field might have it and the field next door won't have it, because of differing crop maturity.”
Most sorghum-producing areas around the world now have ergot. Its first U.S. appearance was in south Texas in 1997, Dahlberg says, after showing up in Brazil in 1995, and it worked its way steadily northward.
"It moved that rapidly up the Americas, progressively moving up the sorghum belt. It has to have the right conditions. We can't eradicate it. It'll be around forever unless somebody comes up with a magic bullet to stop it,” he says.
Other host plants help it survive. Johnson grass is one of the best alternate hosts. "It can sit there in Johnson grass forever and ever,” Dahlberg says.
"All it's looking for is a sterile sorghum. If sorghum gets fertilized, there's no problem. If it's unfertilized, the potential for a problem exists. It's a very interesting disease. Since sorghum is self-fertilizing, it typically has no fertility problems. But when the crop is late and there are cold nights, warm days and high humidity, that's what triggers it.”
If ergot hits, just wait for some help from Mother Nature. "Step back, take a deep breath and let those fields go to full maturity, then harvest. It's hard to do when you're running full bore at harvest time. But just step back and wait a little bit for a freeze or a rain,” Dahlberg says.
Producers with late sorghum fields have more serious problems than ergot this season, he says.
"The bigger issue is going to be lower test weights because of the late harvest. Some sorghum might not mature before it gets out of the field. If farmers receive a reduction in price this year, it'll be because of low test weights,” Dahlberg says.