Current Projects
Fungicide Standardized Trials to Control Soybean Rust (2007-08)
The Southern Soybean Research Program (SSRP) has funded fungicide standardized trials to control Asian Soybean Rust over the past two growing sessions. Headed up by Dr. Melvin Newman, Professor in the Entomology and Plant Pathology Department at the University of Tennessee, the trials were held in Tennessee, Alabama, Georgia and Florida.
Results confirmed that the first application must be made at or before rust infection begins on the lower leaves. Based on the weather, the second application should be made 14-21 days later. Canopy penetration must be made to insure good spray coverage. According to the 2007 study, the first application should be made between the R1 and R3 stage and should be a strobilurin fungicide if the risk of rust is only moderate. If the risk of rust is high than a triazole fungicide must be used or a combination of a triazole plus a strobilurin. Strobilurins are more effective on other late season disease such as frogeye leaf spot, brown spot and anthracnose.
If the threat of rust still exists it is recommend by the study that the second application made between stages R3 and R5 be a triazole, such as Topguard, Domark, Larado or one of the tebuconazoles or a combination of triazole and a strobilurin. Most fungicide labels specify that applications be made prior to the R6 growth stage.
Testing results in 2006 conclude triazoles are better for rust control and that two applications may be needed. Also, when other foliar diseases are likely to occur, a combination of a triazole, plus a strobilurin would give more potential yield. For good control of rust early application once the disease is found is essential.
The Southern Soybean Research Program (SSRP) has funded fungicide standardized trials to control Asian Soybean Rust over the past two growing sessions. Headed up by Dr. Melvin Newman, Professor in the Entomology and Plant Pathology Department at the University of Tennessee, the trials were held in Tennessee, Alabama, Georgia and Florida.
Results confirmed that the first application must be made at or before rust infection begins on the lower leaves. Based on the weather, the second application should be made 14-21 days later. Canopy penetration must be made to insure good spray coverage. According to the 2007 study, the first application should be made between the R1 and R3 stage and should be a strobilurin fungicide if the risk of rust is only moderate. If the risk of rust is high than a triazole fungicide must be used or a combination of a triazole plus a strobilurin. Strobilurins are more effective on other late season disease such as frogeye leaf spot, brown spot and anthracnose.
If the threat of rust still exists it is recommend by the study that the second application made between stages R3 and R5 be a triazole, such as Topguard, Domark, Larado or one of the tebuconazoles or a combination of triazole and a strobilurin. Most fungicide labels specify that applications be made prior to the R6 growth stage.
Testing results in 2006 conclude triazoles are better for rust control and that two applications may be needed. Also, when other foliar diseases are likely to occur, a combination of a triazole, plus a strobilurin would give more potential yield. For good control of rust early application once the disease is found is essential.
Copyrighted © 2008 Kentucky Soybean Association | Kentucky Soybean Board