Seed selection key to managing soybean disease
As spring planting season approaches, soybean growers should be aware that one of the best ways to manage soybean disease is to make sure they plant the right varieties, said an Ohio State University Extension soybean expert.
In fact, seed selection is one of the most important decisions Ohio soybean farmers can make to ensure the best yield outcomes, said Anne Dorrance, a plant pathologist with joint appointments with OSU Extension and Ohio Agricultural Research and Development Center.
"Growers have got to make sure they have the right resistance package, which is one of the best ways to manage soybean disease," she said. "Growers should make sure that the variety they select has the right resistance package for their field, because soybean diseases can severely reduce yields.
"In the rush to plant last season, we had some fields where growers put in the wrong varieties. But now is the time to plan for spring planting in case we have a similar season this year as we did last season."
Of particular concern for the 2012 planting season is soybean cyst nematode (SCN). SCN is always a problem for some fields because once it's present, it doesn't go away, Dorrance said.
Nematodes are microscopic, worm-like soil organisms that, depending on the species, can harm the growth and development of soybeans. SCN can cause substantial yield loss to susceptible soybean varieties, even when egg population densities are low and especially under dry conditions, she said.
If soybeans are going to be planted in fields with SCN, high-yielding SCN-resistant varieties should be grown, Dorrance said.
"For those folks who are managing nematodes, they need to make sure the variety has the SCN package," she said. "If the field hasn't been tested in a while, growers need to get it benchmarked, as we are finding that some fields are creeping past the economic threshold of 5,000 SCN per cup of soil, which can result in damage.
"We're finding that when these numbers are really high, the nematodes adapt to that resistance, so that even the resistant varieties won't manage them."
Dorrance said growers could check with their seed companies, which have ratings of all the seed varieties. Growers can also work with their seed dealers to ensure they get the right variety for fields experiencing any type of disease pressure.
The goal is to prevent a repeat of 2009, she said, when many Ohio growers experienced a white mold outbreak after putting highly susceptible variety into fields that had long histories of having white mold that damaged yields.
"Whomever growers get their seeds from has the best literature because just about all the companies test their varieties," Dorrance said. "Using greenhouse trials, the companies can inoculate plants with the pathogen and evaluate disease resistance."
She said the time is right for farmers to plan their seed varieties.
"Think about this now because you have the time," Dorrance said. "In the lull while you're getting equipment ready, now is the time to do a double check to make sure you have what you need."