Sudden Death Syndrome (SDS) is a major soybean disease in Illinois and across the Corn Belt—flare-ups are still unpredictable and can be especially devastating. Flare-ups are usually associated with early planting and wet, compacted soils that remain saturated during emergence. The only solution has been to make sure the soils and headlands have internal drainage, delay planting till later in May when soil conditions are drier and warmer, and plant a variety that tolerates SDS.
Soybean cyst nematodes (SCN) can worsen the SDS problem. SDS invades roots during seedling emergence and infects the crown region of the soybean seedling. Conditions favorable for SDS include fields that have a high-yield environment, compacted soils, early-planted soybeans, cool/wet soils at planting and wet weather prior to and during flowering. And growers need to remember that SDS—like SCN—doesn’t always show symptoms but still can impact yield.
The increase in SDS outbreaks in the past decade has frustrated scientists and farmers alike—the problem seems to be getting worse and there has been no real effective solutions presented. And you can’t simply rotate out of the problem by planting corn for a couple years because corn residue is actually a host for this Fusarium disease.
But now there are two seed treatments available that are promising, not as a total solution but in addition to using the above mentioned management techniques.
In 2015 Bayer CropScience commercialized ILeVO®, a seed treatment that can control SDS. ILeVO is a hard chemistry containing fluopyram. It is not a biological product like Bayer’s SCN product VOTiVO®. However, ILeVO has both fungicide and nematicide properties, provides control of both SDS and SCN, and supplements VOTiVO. A year ago Michael McCarville, seed treatment technical manager at Bayer CropScience, told the ILSoyAdvisor that they have measured a 2-bushel increase in absence of foliar SDS symptoms and a 4 to 10-bushel increase in the presence of SDS symptoms, when using ILeVO seed treatment.
Syngenta has a similar 2-product combination; Clariva™ and Mertect® 340-F. Clariva seed treatments offer protection against SCN which also reduces the likelihood of an SDS infection. Mertect 340-F has direct activity on SDS.
Both companies stack these two SCN and SDS products along with base fungicides (usually 2 or 3 modes of action) and insecticides. Individual growers have to decide if the cost of this protection is justifiable and if they will receive an actual return from this investment.
Seed treatment fungicides protect your seed investment when soil conditions are less than ideal for germination—a good risk management tool. But the EPA and universities are questioning whether neonicotinoid seed treatments are really that effective in soybeans and worth the investment. Adding on SCN and SDS control will add considerable cost to seed treatments and cost of seed per acre. Each grower has to weigh the cost against the perceived economic benefit.
Agronomist Dr. Daniel Davidson posts blogs on agronomy-related topics. Feel free to contact him at firstname.lastname@example.org.