Are fungicides worth the cost? New study says yes
Input costs are high. On top of fuel, seed, fertilizer and everything else, is it worth it to add the expense of fungicide to your soybean inputs in 2008?
New research says yes. The results of a study conducted in 2007 released recently by Pioneer Hi-Bred International, Inc. show there is a yield gain in soybeans with general fungicide applications.
"Several effects have been reported, including longer green leaf retention or delayed plant senescence, improved carbon dioxide assimilation, increased water use efficiency and increased stress tolerance during flowering and pod fill," according to Pioneer agronomy research scientists Jim Trybom and Mark Jeschke, who reported the study's results in a recent report. "Some combination of these plant health effects and/or an ability to control previously ignored foliar diseases provide an opportunity to increase soybean yields."
The 2007 study was carried out at 10 locations in the Corn Belt from Nebraska to Indiana, with applications of strobilurin fungicides and insecticides, including Asana, Headline, Quadris and Warrior. Six fungicide treatments were applied throughout the season, from R1 to R4, and a fungicide/insecticide combination treatment was applied at each site during pod development, around R3 and R4. Fungicide applications were made by ground at 15- to 20-gallon-per-acre levels.
"The treatment cost (fungicide plus application) was calculated to be equal to two bushels per acre for a fungicide-only application and 2.5 bushels per acre for a fungicide/insecticide application," Trybom and Jeschke say. "Data in the graphs represent a summary of all the years of testing, but not all treatments were included every year."
Despite wide-ranging weather conditions throughout the '07 growing season, Trybom and Jeschke say the final results of the study were consistent. The average yield response ranged from 2.9 to 5.9 bushels per acre, which translates to a 65% to 80% economic yield response, according to the study.
"There was drought in some growing areas and excessive rainfall in others, moderate insect pressure to no insects and moderate to little disease pressure depending on location. In spite of this diversity, nine of 10 testing locations (all except Princeton, Illinois) showed a yield response to the fungicide treatments," the researchers say. "All fungicide applications improved yield over the untreated check when data were averaged across locations and varieties."
Factors beyond Mother Nature can influence fungicide efficacy, as indicated by the study. Treatment amounts and methods can change the cost efficiency of applications as well.
"These results may not be comparable strictly to aerial applications. Good coverage is important in controlling foliar diseases," according to Trybom and Jeschke. "Also, if applying by ground rig, wheel traffic from the sprayer can decrease yield slightly. The amount of this yield decrease will depend on spray boom width and soybean row width."