June 2, 2006
There are certain steps all rice growers must take to establish a crop: get a healthy, uniform stand with a good variety, fertilize properly, water effectively and control weeds, especially grasses.
However, once the crop is in permanent flood, then the focus turns to protecting its yield potential, and that means guarding against disease.
“It's very important to protect your crop once it's established,” says Rick Cartwright, plant pathologist at the University of Arkansas. “With modern varieties, I would say controlling disease is one of the most important factors after mid-season, because you have good yield potential established and you want to make sure that gets in the combine.”
Like insects and weeds, untreated disease can have a dramatic effect on rice at harvest. Sheath blight, kernel smut, false smut and panicle blast are economically damaging rice diseases that attack the plant. “If those upper leaves and sheaths are damaged by sheath blight prior to grain fill, you're going to have a yield loss,” says Cartwright. “Fungicides slow down that process of damage to keep the plants healthy longer.”
The best way to stop losses from disease involves timely treatments with effective fungicides. Not only can fungicides increase yields, they also improve milling quality. “The two go hand-in-hand,” says Cartwright. “Our data has always indicated if you don't have yield loss from disease, then you won't have a milling quality loss.”
Even though milling quality may be secondary to yield in the minds of growers, it is still a significant factor in determining grain value. Fungicides promote better milling quality by reducing damage to crops from disease. Since different diseases attack rice in different ways, there are various causes for lower milling quality.
Sheath blight, for instance, which is considered the most important disease in the Delta due to the sheer number of acres it infects, will take out the upper leaves and canopy of a plant before grain fill is complete, leaving blank grains.
“In the case of sheath blight, the plant will sacrifice some grains in order to fill others because it's under attack,” says Cartwright. “But the grain fill itself is also affected. You'll get smaller grains, lighter grains and grains where the starch is not laid down properly.” In these cases, grains are more susceptible to break during milling, resulting in a loss of head rice, which is what growers need to protect most. Timing is a critical part of effective fungicide applications. Growers have a few options regarding when to spray, but many are finding an advantage in preventive applications.
Earl Garber of G&H Seed Company in Crowley, La., is sold on preventive treatments. In 2005 he conducted a series of trials throughout southwest Louisiana using three different application timings of Quadris fungicide to determine the benefits of early, preventive spraying.
A 12-ounce rate was used for the early application at panicle initiation, while 9 ounces were applied at either the mid-stage of panicle development or boot split. By season's end the results were clear. The early 12-ounce application proved to be significantly more profitable.
“It was better across the board,” says Garber. “We saw better total yield, head rice and milling quality with the 12-ounce spray shortly after panicle initiation.” Garber's recommendation is to spray preventively. “An early 12-ounce application of Quadris as a preventive is definitely the way to go.”
Recognizing the inputs and hard work they've invested during the season, growers can't afford to have their crop ruined by disease. However, growers do have to consider return on investment when deciding inputs. “It's all about protecting the crop potential that you have established,” says Cartwright. “In Arkansas, that's typically worth about $25 to $30 per acre.”
With the rising cost of inputs, especially irrigation costs, growers need to find ways to maximize their returns. Fungicide applications are one area where growers can get the most out of this necessary purchase by choosing products economically.
Gerald Bednar, a rice and soybean consultant in Stuttgart, Ark., recommends Quadris plus Quilt because they give growers more for their money. “Just because a product is cheaper doesn't mean it's as cost-effective,” says Bednar. “I've done many tests to determine which fungicides give the most control for the money, and Quadris plus Quilt always comes out ahead.”
Growers find that tank-mixing Quilt with Quadris forms a combination of cost-effective protection. “I run nothing but Quilt and Quadris on my rice,” says Chris Roberts, who farms 350 acres of rice in Heth, Ark. “We ran some Quilt by itself with good results, but we also used a mixture of 14 ounces of Quilt and 6 ounces of Quadris and it performed well.
“The Quilt/Quadris combo was something new for us,” says Roberts. “Last year I used more Stratego, but this year I made the complete switch because I think Quilt and Quadris are just better products.”
For more information, visit the Syngenta Crop Protection Web site at www.syngentacropprotection.com or FarmAssist at www.farmassist.com, or contact the Syngenta Customer Resource Center at (866) 796-4368.
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