Update on soybean diseases and their management

There were several diseases that appeared in soybean fields in 2016. While diseases were not common early in the season, by late July they became more prevalent. Some of the most prevalent diseases during the 2016 season were bacterial pustule, frogeye leaf spot, sudden death syndrome (SDS), and white mold. This talk will focus on these specific diseases and provide updates on management of soybean diseases in general

Update on soybean diseases

Although parts of Iowa experienced dry conditions during the 2017 growing season, several important diseases were observed. Early season diseases were not common, but by late July prevalence increased. White mold was the most damaging disease in the northern part of the state. There was also limited, late development of sudden death syndrome and pod and stem blight (Diaporthe). Tobacco ringspot was found across much of Iowa very late in the season. This presentation will focus on these specific diseases and provide management updates for soybean diseases in general

Research update on sudden death syndrome

Much of the sudden death syndrome research is funded through the soybean check off from Iowa Soybean Association, North Central Soybean Research Program, and the United Soybean Board. Recently, ISU received USDA and some industry funding as well to research this disease. We thank all of our sponsors for this research

Soybean disease year in review—2015

One thing is for sure—the 2015 season produced several interesting dilemmas for soybean farmers. Early in the year we had seedling diseases mixed with phytotoxicity from new seed treatments and certain herbicides. During the midseason, some fairly uncommon diseases crept in including soybean viruses and an outbreak of Phyllostica leaf spot. At the end of the season, white mold, Diaporthe and sudden death syndrome (SDS) were common, with SDS being one of the most prominent diseases in 2015. In some parts of Iowa SDS appeared a few weeks earlier than in 2014. Also, as if to add insult to injury, green stem disorder (GSD) was quite prevalent in many parts of the state

Management of Soybean Rust with Foliar Fungicides

Soybean rust has the potential to decrease profits directly by reducing yield and/or increasing the cost of production. There are effective fungicides available for management of soybean rust (Miles et al. 2007). However, correct application timing of foliar fungicides and adequate coverage is important for management of soybean rust and maximizing soybean yield

Risk of Sudden Death Syndrome Increasing with Rains

One thing we have learned from outbreaks of sudden death syndrome (SDS) in years past is that this disease likes it wet. Last year we wrote about the risk of SDS increasing with the early season rain. But at the end of the article we threw in one caveat — soybeans were planted very late in the season, which reduced the risk of SDS developing. And after we published the article, the rains essentially stopped. Fast forward to the end of the 2013 season -- we still had some SDS in parts of Iowa in 2013, but it was not as nearly as bad as it could have been

Soybean Rust Overwintering in the South

Despite soybean rust infecting fields in Iowa last fall, the pathogen needs to retrace its steps to get back to Iowa in 2008. The first critical step is for the pathogen to survive somewhere over the winter in places like Florida, Texas or Mexico. An extensive study on the survival of soybean rust was completed in Florida by W. Jurick, J. Marios, D. Wright and P. Harmon

Soybean rust update

Any daylily or tulip enthusiasts may be bemoaning the recent cold snap that left many early-greening plants very sad across much of Iowa. Well, cold weather can be our friend as well. On April 7 and 8, a cold front pushed as far south as the Florida Panhandle, and kudzu growth was slowed or knocked back from this record-breaking frost. The freezing temperatures on the rapidly growing kudzu in this area could reduce the buildup and potential spread of soybean rust for several weeks. This frost came much later than their March 15 frost-free date

End of Season Soybean Rust Update

Following the pattern of 2010, soybean rust never really got off the starting line in 2011. As of mid-October, soybean rust has been found in two Georgia counties, seven Florida counties and one Louisiana county in the continental United States. The disease was also found in parts of Mexico and Puerto Rico earlier this year; there is a recent report (early October) out of Tamaulipas, Mexico (Figure 1)