Fungicide Seed Treatment Considerations for 2019

 

With the excessive soil moisture and flooding that has occurred throughout South Dakota, growers may be thinking about using a fungicide seed treatment this planting season. Fungicide seed treatments provide protection against seed-borne and soil borne pathogens which may interfere with seed germination or may infect the seedling soon after germination. Nematicide seed treatments provide protection against nematodes such as soybean cyst nematode (SCN). Seed treatments enhance plant stand and plant vigor when the soil is cold and wet.

 

However, not every field can benefit from fungicide seed treatments. The probability of a return on seed treatment investment depends on several factors listed below. These factors may be used to help growers make their decision on whether a seed treatment is a beneficial investment for them.

 

 

 

Fields which have had plant pathogens (such as Phytopthora, Pythium, SCN and others) in the past are likely to benefit from seed treatments. Testing the soil for various pathogens; especially, soybean cyst nematode may aid decision making about seed treatments. Testing for SCN is free of charge to South Dakota producers courtesy of the SD Soybean Research and Promotion Council.

 

 

Fungicides applied on the seed provide protection against seed-borne pathogens such as Phomopsis spp which causes seed decay and interferes with germination. Using clean, disease free seed reduces the need to apply fungicide seed treatments for this purpose.

 

 

Planting too early when the soil is cool (below 55 F) and wet or slow to warm-up increases the chances of seed rots and root rots caused by Pythium spp and Fusarium spp. Delaying planting to when soils are warmer and not too wet will reduce the risk of root rots developing.

 

 

A well-drained field has low incidence of root rot pathogens such as Pythium and Phytophthora. These pathogens are common in water-logged or soil compacted areas of the field.

 

 

Varieties vary in their susceptibility to plant diseases. For instance, resistance to Phytophthora is available in soybean cultivars, as well as resistance to SCN. A soybean variety with resistance to SCN may not require nematicide seed treatment provided the SCN counts in the field are not very high (<6,000 eggs/cc of soil).

 

 

If seed treatments are decided upon, an applicator certified to apply seed treatment should treat the seed. The decision to use a given active ingredient should depend on the pathogen to be managed. Pythium and Phytophthora (water-mold pathogens) are managed with three common active ingredients: metalaxyl, mefonoxam, and oxanthiopiprolin. SCN is managed with common nematicides: Clariva, Ilevo, Poncho Votivo, Avicata complete, Nemastrike, and Aveo. Other seed and root rot pathogens can managed with several products available on the market. For a list of products registered in South Dakota, view the South Dakota Pest Management Guides.

 

Federal regulations require treated seed to be dyed with a colorant to avoid mistaking the seed for other purposes other than planting. Seed treatment done at planting within the planter box is exempt from the dying requirement. Also, when the treated seed is in storage, the bag or storage container must be labeled with the active ingredient which was used to treat the seed.

 

Treated seed should always be handled safely during storage and planting. Follow safety guidelines on the product label. Always use personal protection equipment recommended on the pesticide label and on the treated seed bag tag. Follow the label directions to know how to deal with spilled or leftover seed.