Disease management should be done prior to planting

Published on April 4, 2020

“If the forecast holds true, it looks like it is going to be another year of excessive soil moisture and possible flooding,” states South Dakota State University (SDSU) Extension Plant Pathologist Emmanuel Byamukama and SDSU Extension Plant Pathology Field Specialist Connie Strunk in an article published on Feb. 11. 

            Byamukama and Strunk note increased levels of soil moisture have implications on plant stand establishment as well as root rot and nematode infestations. 

Management options

            “Managing root rot and nematodes requires taking action before planting since there are no in-season treatments that can control them,” the two pathologists say. 

            Despite this, Byamukama and Strunk note there are a few pre-planting management options growers can use for disease management. 

In low-lying fields with poor drainage or a history of root rot, Byamukama and Strunk say seed treatment may be needed.

            They explain fungicide and nematicide seed treatments provide protection against seed-borne and soil-borne  pathogens and nematodes, which may interfere with seed germination or infect the developing roots after germination.

            “Seed treatments enhance plant vigor in the presence of soil-borne and seed-borne pathogens,” the plant pathologists say. 

            “A grower’s decision to use a given active ingredient should depend on the pathogen they need to manage,” say Byamukama and Strunk. “Pythium and Phytophthora are water-mold pathogens and are managed with three common active ingredients – metalaxyl, mefonoxam and oxanthiopiprolin.” 

            They also explain common nematicides used to manage soybean cyst nematode are Clariva, Ilevo, Poncho Votivo, Avicata Complete, Nemastrike and Aveo EZ. 

            “Other seed and root rot pathogens can be managed with several products available on the market,” they explain. 

Another management strategy the two recommend in wet seasons is delayed planting.

            “Time of planting can influence the level of certain root rots in crops,” they explain. “Planting too early when the soil is wet and below 55 degrees increases the chances of seed and root rot. It is recommended to delay planting to when soils are warmer and not too wet to reduce the risk of these rots developing.” 

Important considerations

            Byamukama and Strunk note it is important to recognize seed treatments don’t compensate for poor seed quality. 

            “Even with seed treatments, cracked, shriveled or poorly stored seed many don’t germinate well. Growers need to use clean, disease-free seed to reduce inoculum on the seed,” they say. 

            They also note safety while treating and handling treated seed is crucial. They urge growers to follow safety guidelines on the product label, follow label directions when dealing with spilled or leftover seed and use personal protection equipment recommended on the pesticide label and the treated seed bag. 

            “One effective tool in plant disease management is variety and hybrid selection,” Byamukama and Strunk say. “Varieties and hybrids vary in their susceptibility to plant disease.” 

            “Resistance genes in varieties can sometimes fail to manage pathogens due to persistent use of the same resistence gene,” they add. “It is important to rotate different resistance genes within varieties to avoid pathogen resistance from developing.”  

            The last thing Byamukama and Strunk encourage producers to do is to carry out soil tests for various pathogens. 

            “Flooding can move soil within and between fields and spread soil-borne pathogens. Therefore, it is beneficial to carry out soil tests for varous pathogens in subsequent seasons, especially for the soybean cyst nematode, which is the number one pest of soybeans,” they explain.

            They continue, “Testing soil for various pathogens may aid in decision making such as seed treatment and variety selection.” 

            Information in this article was compiled from an article titled Pre-Plant Disease Management Considerations found at extension.sdstate.edu/pre-plant-disease-management-considerations.

            Hannah Bugas is the assistant editor for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.