If you've attended ISU Extension field days in the past two years, you probably heard the word "oomycetes" talked about by agronomists, particularly in reference to seedling diseases of soybeans and corn. Phytophthora sojae and Pythium disease species are oomycetes, and they can result in stand loss early in the season if conditions are particularly wet.
A farmer's main defense against seedling blight, and root and stem rot, caused by Phytophthora sojae is to plant soybean varieties that are resistant to this disease. However, management of Pythium requires use of a combination of practices, says Alison Robertson, ISU Extension plant pathologist. The practices include seed treatments, tillage and soil moisture management.
Stem and root diseases of soybeans cause significant yield loss
To help farmers, crop consultants and Extension educators improve their knowledge and understanding, and most importantly the management of oomycetes, Jim Kurle, a professor of plant pathology at University of Minnesota, has produced a webcast titled "Oomycete Diseases of Soybean and Current Management". You can view it at the Plant Management Network website.
This webcast, published by the Plant Management Network's Focus on Soybean newsletter, discusses the biology of Phytophthora and Pythium pathogens, as well as environmental factors influencing disease development and the unique aggressive characteristics of these diseases. How to manage diseases caused by oomycetes is also discussed, emphasizing the need to integrate the use of resistance, chemical controls and cultural practices.
The research in this presentation was funded by a USDA grant on oomycete diseases. Through links and attachments embedded, the presentation leads viewers to other important resources funded through this grant, information that is available from various universities and programs. The 20-minute presentation is fully open access.
ISU studied fungicides on disease control, yield in 2012 and 2013
This and other Focus on Soybean presentations can be viewed at the website. Webcasts on other crops are found at PMN's Education Center online. Focus on Soybean is a publication of the Plant Management Network, a nonprofit source whose mission is to enhance the health, management and production of agricultural and horticultural crops.
Foliar fungicide test results. Also, now available are ISU test results of foliar fungicides used on soybeans. Go online and read the report explaining ISU's results for foliar fungicides regarding disease control and yield during the 2012 and 2013 growing seasons in northeast Iowa. The results are in ISU's Integrated Crop Management newsletter.
"Foliar, stem and root diseases of soybeans are significant in terms of yield loss for farmers," says Robertson. "Use of fungicides is one of the options in managing diseases. Fungicide use on soybeans in the 20 largest soybean producing states has increased from less than 1% of soybean acreage in 2002 to 11% of soybean planted acres in 2012."