Soybean South


Farmer Sees Extra Benefits
In Fungicide Sprays

Mississippi soybean producer, Brian Byrd, describes how he protects
his crop against Asian soybean rust, controls secondary diseases,
increases yields and improves quality.


Because of the threat of Asian soybean rust last year, Mississippi grower Brian Byrd sprayed 1,244 acres of late Group IV and early Group V soybeans. He applied Domark/Orthene as a preventative treatment for Asian soybean rust, but says the fungicide also controlled his secondary diseases – and increased his yields.

“I’ve experimented with fungicides a little on soybeans in the past, but when the rust came into play, we sprayed much more acreage last year,” says Byrd, who farms near Sunflower, Miss. “We applied Domark as a preventative for rust, which we don’t believe ever reached our fields, but we found that it controlled our secondary diseases, including frog-eye and purple seed stain. We didn’t have either one in our treated beans, but saw frog-eye in our untreated plots.”

In addition to controlling secondary diseases, the fungicide enhanced his yields due to improved plant health.

“There was not only a difference in disease control, we also made a consistent yield increase,” he says. “The fungicide helps keep the soybean plant healthier and allows it to mature to its full yield potential. We had anywhere from an 8- to 12-bushel yield increase.”

Byrd divided his treated 1,244 acres among four different farms and left an untreated check plot on each farm. Overall, the Domark/Orthene treated soybeans yielded between 8 to 12 bushels per acre higher than the untreated soybeans. In fact, the first farm Byrd harvested averaged 61.5 bushels with the tankmix, and the untreated soybeans averaged 48 bushels.

“We proved consistent yield gains by comparing treated acreage to 10-acre check plots,” he says. “I was skeptical at first, but the overall yield difference between the fungicide-treated acreage and the untreated plots made me a believer.”

This soybean/rice grower farms about 3,200 acres of soybeans. With his inputs and his soil type, he expects to average 50 bushels per acre. “We aim for 50 bushels every year and sometimes go beyond that,” he says. “We irrigate all of our beans; most are watered down the middle, but we have 1,000 acres that we have to flood irrigate.”

In addition to safeguarding against Asian soybean rust, controlling secondary diseases and increasing yields, the fungicide improved soybean quality for Byrd. “We also saw a quality difference between treated and untreated beans,” he says. “While we had a little damage on the untreated beans at harvest, we had absolutely no damage on our treated beans.”

Byrd made one aerial application of Domark/Orthene on July 19 last year when the soybeans ranged from R3-R5. He used five ounces of Domark and 0.6 pounds of Orthene. The fungicide tankmixed well with Orthene insecticide, he says. “The Orthene helped us with our insects, mainly stinkbugs,” Byrd adds. “Our untreated plots suffered from potato leaf hopper and stinkbug damage, but we had none in our treated beans.

“With the yield increase and the improved quality, the return very much justified the cost of the material and the application,” Byrd notes. “Domark also gives you peace of mind as a rust insurance policy, and you get the added benefits of controlling secondary diseases such as frog-eye and purple seed stain.

“We like it so much that we’ve already budgeted Domark/Orthene into our program for this season,” the Mississippi producer adds. “We’ll use it over a wider acreage – on all of our Group V beans and maybe some of our Group IVs.”

A message to Georgia growers
Asian soybean rust appeared in a number of locations in Georgia last year and Domark was one of the products that was evaluated by University of Georgia plant pathologist Dr. Bob Kemerait. “We mostly looked at two applications of Domark,” he says. “I was quite impressed with the efficacy. We prefer using any fungicide in a preventative fashion, applying it prior to infection. Domark was as good as or better than any other fungicide we tested in our preventative trials. This triazole fungicide is a good example of what I consider a very strong product in managing rust.”

Dr. Kemerait’s tests last year showed although best results are achieved when a fungicide is applied before the crop is infected with Asian soybean rust, Domark is among the top fungicides for curative activity.

However, he cautions that timing a curative application of any fungicide is extremely difficult.

“When a grower sees soybean rust, it is either almost too late or it is too late to apply a fungicide,” he explains. “I see the disease sooner because I’m looking much closer. If I detect a very early infection in a field, then it’s not too late for an application of a triazole type fungicide.

“However, rust is such a difficult disease to see when it starts out that if a grower sees disease in his field, he probably has missed the application window,” Kemerait adds.

“Rust was widespread in Georgia last year, but it came in a little late. We estimate that between 60 and 70 percent of our growers sprayed at least one time for rust.

“I feel every spray was justified. We’re a 170,000- to 180,000-acre crop, but that’s up from 10 percent sprayed for diseases like frog-eye leaf spot the year before.

“What’s going to happen to the rest of the country? The way rust has been found in Alabama, Georgia and Texas, if it doesn’t spread further, we will have to ask ourselves ‘why not’?

“My message to our Georgia growers is go ahead and budget in the preventative sprays. We have rust in the state right now, and there’s absolutely no doubt that soybean producers in Georgia will have to face it this season. If they have a good crop with a good yield potential, they will probably have to spray at least once. So go ahead and budget for it.”

Timely Applications Affect Yield Increase In Georgia

“Growers often look at cost instead of return when considering a new practice,” says Dr. Bob Kemerait, plant pathologist at the University of Georgia. “We conducted five fungicide trials last year where we had rust. In one of the trials, I waited until rust was in the field and didn’t catch it early enough. Because of the delay in application, we didn’t get good results.

“In the other four trials where we made timely applications, we saw a yield increase of at least six bushels per acre of treated over our check. Some treated plots made 16 to 18 bushels per acre more than the check.

“It costs the grower somewhere between $20 to $30 to make two fungicide treatments. At $6 beans, you make money with a 6-bushel per acre increase,” he notes.

“If you look at the 16- to 18-bushel per acre difference, you make a lot of money.”