Get defensive with 2011 soybean varieties
Sudden death syndrome threw a wrench in some soybean farmers' crop this year. But, that's not the only disease that threatened the crop this year. So, can you avoid these types of disease issues next year?
You can start planning for this right now by selecting the right soybean varieties, according to Iowa State University Extension plant pathologist X. B. Yang. Though yield is the biggest draw when picking your seed, Yang recommends looking for the best defensive properties when selecting your 2011 varieties if you were pressured by disease this year.
"As producers plan for the 2011 soybean growing season, many will make disease management a high priority because of the outbreaks of sudden death syndrome (SDS) in 2010. Some soybean producers will select soybean varieties for the coming season according to what happened during the last season," Yang says. "While picking up SDS resistant or tolerance varieties may seem to be a good decision, the risk of white mold should be considered as well, particularly in northern Iowa where white mold was widespread in 2009.
Don't base all your decisions on past years, though. Look at the conditions that encourage each disease to flourish and take Mother Nature into consideration. "It is too early to say what disease may have outbreaks for the coming season," Yang adds.
White mold thrives most in cool, wet weather. Though daytime temperatures averaged just above normal during much of the growing season in Yang's state of Iowa, the mold adapted and managed to spread despite the limited weather window. As a result, soybeans affected by the disease this year could be endangered in 2011 in fields lacking any defensive traits.
"For growers doing corn-soybean rotation, fields that had white mold in 2009 still pose a serious risk for white mold in 2011 production, with level of occurrence depending on summer weather conditions," Yang says.
In gauging the prevalence of SDS in 2011, it's less about the weather and more about the incidence of the disease this year. And, with as much as there was in Iowa, for example, in 2010, it's a safe bet to be a threat next year.
"The wide spread of SDS in the 2010 season suggested that SDS fungus was present in almost every Iowa soybean field. The disease was also prevalent in 2009 although not as severe as 2010 season," Yang adds. "This means that the SDS pathogen is widely present in Iowa and inoculums is unlikely a limiting factor of outbreak in Iowa. Therefore, the risk of SDS is equally serious."
So, taking these diseases into consideration, look at which one affected your crop more in 2010 for initial direction in selecting your 2011 soybean varieties.
"If only one disease is a concern, the answer is simple, select a variety resistant to that disease. If both SDS and white mold are major production concerns in a particular field, I would use varieties to manage SDS risk and consider a fungicide to manage white mold risk when its risk becomes more certain," Yang says. "Effective fungicides now are available on the market to control white mold without yield penalty when mold is a threat in summer.