What is in this article?:
- Growers, weather stopped early soybean rust outbreak
- Needed help from Mother Nature
- High expectations for 2013 crop
• Rust was detected along a southern tier of North Carolina counties on Sept.12, but Mother Nature, a well-coordinated system of sentinel plots, and timely actions by growers stopped rust in its tracks.
Needed help from Mother Nature
With ASR making a record early arrival, growers needed some help from Mother Nature to manage the potentially yield destructive diseases. They got it!
Fountain says the average daily air temperature for the previous four years for the time period when soybeans would have been at risk in Kenansville, N.C., is 66 degrees F and the first frost date is from Oct. 21-31.
During that time frame, when soybeans were at risk, conditions were ideal for soybeans to finish their productive stages, but not good for rust development.
Like most areas of North Carolina and Virginia, the North Carolina Extension ag agent says most growers in Duplin County didn’t see a risk from ASR, and, therefore, didn’t spray soybeans for that disease alone.
Koenning adds that North Carolina State Extension doesn’t recommend spraying soybeans with a fungicide to control ASR if soybeans are not yet blooming, if they are blooming, but rust has not been confirmed within 100 miles, or if full sized seeds are present in the top of the plant (stage R6).
Such pre-bloom applications have seldom improved yields, and repeated applications will likely be needed to provide season-long protection against rust.
The higher labeled rates tend to provide more days of prevention, and may thus require fewer applications.
The triazole fungicides, alone or in combination with a strobilurin fungicide, will probably provide better prevention of rust than a strobilurin alone, he adds.
Other parts of the Southeast have had more of a battle with Asian Soybean Rust.
By the end of October virtually every county in Alabama and Mississippi had documented cases of rust. In Louisiana and South Carolina about half the counties were infected with the disease.
Little rust was reported in Tennessee, Kentucky and Virginia and appeared to be no threat prior to the first frost in these states.
In South Carolina, Extension Corn and Soybean Specialist David Gunter says this year’s soybean crop went through some stress early in the season from drought, but late season rains helped growers produce what appears to be one of the best soybean crops on record.
“We had some issues with kudzu bugs, but not as severe as we thought they might be.
“Overall, if we can finish this crop out, it will almost certainly be the best soybean crop I’ve seen since I’ve been working with the crop,” Gunter says.