Soybean Disease

C.O.R.N. Newsletter Articles

  1. Roots from plants exhibiting flooding symptoms

    How to Distinguish Flooding Injury from Phytophthora or Pythium Root Rot in Soybeans

    Author(s): Anne Dorrance

    Flooding injury occurs when soils are saturated for several days and anoxia develops.  The roots are killed, as are the nodules that are home to the nitrogen fixing bacteria. The field has an “interesting’ smell but the key symptoms of this injury are on the roots. Dig up a few plants – if it is flooding injury the outside of the root – the epidermis will be easily pulled off the root leaving the white center – looks like rat tails (Figure 1). In addition, the nodules will be gray and easily crushed.

    Issue: 2021-23

  2. How to Identify Late Season Soybean Diseases in 2020

    Author(s): Anne Dorrance

    Sclerotinia stem rot – The nights have been cool this growing season, even when the days were very warm.

    Issue: 2020-27
  3. Frogeye leaf spot

    Frogeye Leaf Spot - Is It Worth Spraying in 2019?

    Author(s): Anne Dorrance

    Several reports over the last two weeks of heavy frogeye leaf spot pressure in some fields as well as low to moderate pressure in others.  This disease will continue to increase and infect new foliage as it develops on these late planted soybeans. Based on our previous research, only once (2018) in 14 years of studies did applications at the soybean growth stage R5 contribute to preserved yield.  At the R5, the leaf at the terminal is fully developed and the pods at any one of the top four nodes is fully expanded, but the seeds are just beginning to expand.

    Issue: 2019-27

  4. Western ARS Agronomy Field Day, Wednesday July 17, 2019

    The Western Agricultural Research Station Agronomy Field Day will be held July 17th. The station is mostly planted but everything went in on the edge – as you saw it on your farm too. Hear our researchers thoughts and recommendations on how to manage this interesting season.

    A couple of items we will walk through are:

    Issue: 2019:20

  5. Early Yellowing Soybeans

    Author(s): Anne Dorrance

    Soybeans across the state range from ready to harvest to still flowering.  But in some fields, the yellowing was limited to pockets - some was sudden death syndrome or brown stem rot, charcoal rot, Phytophthora stem rot, and soybean cyst nematode.  There are some other early yellowing situations that we are still working on an accurate diagnosis, but yellowing in these cases may be linked to fertility issues and/or related to late flooding injury.  I think in 2018 we’ve observed just about everything, and it was all dependent on where in the state the soybeans were grown, how much rain occu

    Issue: 2018-29
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Publications

  1. Managing Soybean Rust, Bulletin SR2008

    Managing Soybean Rust, Bulletin SR2008. Publication covers specifics of soybean rust identification and  management. General section of the publication cover the use of fungicide sin general for disease control including description of products and their activity, application information and modes of action.

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