By Anne E. Dorrance
With lower prices and higher input costs in todays soybean farming operations, some farmers are looking where to shave a few dollars off their costs of farming. Based on the calls directly from farmers on which seed treatments to use – it is not too hard to figure out where some of those savings might be coming from. This used to be general practice but there are ways to do this to be sure it really is saving farmer’s money.
- Make absolutely sure that this seed is a candidate to use again. The harsh reality of the new generation of technologies that go into the new soybean varieties is that it probably takes the total profit of the US soybean crop to go from discovery, development, US & European government approvals, and producing that seed. Companies are forced to protect that investment and in reality – part of how we have raised the state yield average from 30 bu/A to 52 bu/A is because of these improved varieties.
- Make sure your seed is healthy. Germination tests are very important, it was a tough fall and as you look at that seed there may be a lot of discolored, moldy seed from Phomopsis or Cercospora. There may also be splits – as some seed was harvested last fall well below 13%. Some of our seed was at 9% before we could get to the fields. So this will reduce your viability. Ohio Seed Improvement Association (614- 889-1136) does have the appropriate seed germinators to run these tests for a fee. Also, for testing at home, use one of your baking dishes, line it with paper towels, and run water over it, drain the excess water, then scatter 100 or more seeds over the bottom of the dish. Cover again with more paper towels, add just enough water to moisten that top layer. Leave on the counter or in a warm room for 5 to 6 days, keeping the seed moist but not swimming in water, and check the germ. If it is not over 85%, it is probably best to buy new seed. Note use several pans from seed collected from the different fields.
- Don’t repeat problems, diseases from last fall. Three pathogens were in different areas of the state that can be carried with seed.
a. Sclerotinia stem rot or white mold. This popped up in several areas last year. The sclerotia, those hard black irregular shaped structures, can be harvested with the seed and then if not properly cleaned can end up back in the soil in the seed furrow. Also, some seed will have mycelium of the fungus, that white fluff that you see on the stems. This can also contribute to poor stands in the spring.
Sclerotia ofSclerotinia Sclerotiorum
b. Phomopsis seed decay. White, chalky, moldy seed was quite common this year, especially in areas of the state that had a lot of rain during pod fill. This disease will directly impact seed viability. But some seed will carry the fungus on the outer layers, but it won’t have reached the internal layers. When a fungicide that targets this fungus is used, germination of the seed lot can be improved. Again, if overall germination is below 85% and the seed is really moldy, best to get new seed.
Phomopsis seed rot
c. Purple seed stain. Especially in the southern counties, Cercospora blight, in addition to frogeye leaf spot made a late season appearance. First, a request, if you do have seed with symptoms of purple seed stain, there is a study, funded by the soybean check-off, in progress which is looking at all of the strains that cause this disease across the U.S. It helps us to have samples in this study. Please send these to me @ 1680 Madison Ave., Wooster, OH 44691. We will verify that they are the right fungus and ship them to our colleague.
Cercospora Leaf Blight & Purple Seed Stain
d. What seed treatments will work to protect germ and limit spread of these pathogens? Most of the data available today is based on Phomopsis, and there are a number of active ingredients that can protect seed – when the seed is contaminated with mycelium but not the germ, and when an infected seed is placed right next to a healthy seed in the seed furrow. Look for seed treatments that have one of the following active ingredients: fludioxonil, fluxapyroxad, ipconazole, PCNB, penflufen, prothioconazole, pyraclostrobin, or sedexane. Data is from the combined studies of members of the NCERA-137 Soybean Pathologists from the Land Grant Colleges in the soybean producing states.
e. The most important advise ROTATE FIELDS. In addition to the ability to survive or contaminate seed, all of these pathogens have survival structures in the soil or on soybean residu To get off on the right foot for 2018 – plant the fields that has problems, lower yields, plants with symptoms of early dying from a plethora of problems, or moldy seed to corn preferably. Or if you must plant soybeans, work with your seed dealer to get the best disease resistance package in that field. We can solve all of these problems by planting varieties with better disease resistance packages targeted for our areas.