Experts give soybean update at Kansas Soybean Expo in Topeka

by Doug Toburen

The Kansas Soybean Association’s 2010 Soybean Expo was held recently in Topeka, Kan., and kicked off with a look into the future for soybean producers.

Leading off the program was Bill Schapaugh, Kansas State University soybean breeder.

Although Schapaugh’s discussion on soybean cyst nematode (SCN) may not have been a new topic, the research being done at K-State continues to be updated.

According to him, one current SCN study looks at the diversity of the disease in different counties in Kansas.

“After taking over 60 soil samples in Kansas, SCN was detected in 78 percent of them,” Schapaugh explained. “The majority of these SCN populations are big enough to cause an economic problem for the producer.”

In order for growers to combat SCN, Schapaugh recommended they continue to rotate soybeans with non-host crops, plant SCN resistant varieties and rotate resistant varieties.

“The key is not using the same crop or varieties twice in a row,” he said.

Schapaugh urged growers at the Expo to familiarize themselves with different soybean varieties listed in the 2009 Kansas Crop Performance Tests.

“There are some big differences in varieties,” he said. “We have even seen some varieties that limit the reproduction of SCN.”

Staying with the trend of continued K-State soybean research, Larry Buschman, Kansas State University entomologist, discussed research being done on the Dectes stem borer.

The Dectes stem borer is not a new insect it is also referred to as the soybean stem borer, sunflower stem borer and sunflower stem girdler, according to Buschman.

“The Dectes stem borer has made a shift from wild hosts to soybeans and sunflowers in Kansas,” he explained.

He continued that much of the damage done from this insect over the last several years has been spread throughout the western two-thirds of Kansas.

“One region of the state where we have not seen the presence of Dectes is in eastern Kansas,” Buschman said. “However, where they are present they can be devastating.”

The main problem that Buschman has seen in his research is that it is hard to use insecticides on the stem borer since their presence is very extended.

“Since they are around so long it is hard to eliminate them with insecticides,” he said. “It takes more than one treatment which gets to be expensive.”

The other issue with their extended staying period, according to him, is that re-infestation is a problem.

To date, according to Buschman, there are no resistant varieties available to plant.

“We are working on host plant resistance and getting some good results though. Results that are almost equivalent to using chemical,” he explained.

Buschman reminded producers that this, like much of the research K-State does, is long-term so it will take a while before many options are available.

Stu Duncan, Kansas State University crops and soils specialist, followed Buschman on the update schedule where he discussed soybean seed and foliage fungicide.

“We want to see what kind of response we can get when looking at planting date, seed treatments and foliar fungicide,” Duncan explained.

The research looked at seed treatments because soybeans are being planted into cooler soils.

“When planting in soil temperatures below 60 degrees, growth is inhibited and seed rot is promoted,” he said.

In addition to that, no-till soil temperatures tend to be even cooler than conventional tilled soil temperatures, which, according to him, can cause stand losses.

Foliar fungicides were included in the research to see if seed quality and yields could be improved.

The research, according to Duncan, took place on three sites—Manhattan, Scandia and Belleville.

“All three sites were planted at two times, the first of May and the first of June,” he explained.

Although it was the first year for the research, it has turned up some interesting results.

“Some of the differences in the results were due to weather but that is why we have multiple sites,” Duncan said.

In the end, the results showed that the seed treatment effect did show some yield increase, according to him.

“Regardless of the planting date we did see a positive reduction in incidence of leaf disease with the fungicide application, however, there was very light disease pressure,” Duncan concluded.

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