Resistant Cercospora, soybean rust impact and a new soybean fungicide were topics at a recent meeting of soybean disease workers. Researchers will continue monitor the diseases and their spread, as well as host plants.

Soybean pathologists from Kentucky and Indiana have both reported the presence of the fungus, Cercospora sojina, that are resistant to the strobilurin fungicides.  This fungus causes frogeye leaf spot on soybeans.  There are lots of Cercospora species that cause disease on a number of different hosts (gray leaf spot on corn; Cercospora on beets etc.) To date we have not identified any Cercospora sojina isolates that are insensitive to these fungicides.  More monitoring will take place in 2014. 

Soybean rust and hosts

Much of the kudzu was killed back, but unfortunately it had been dry in some parts of the south, so the rust spores survived in some areas.  Predictions on soybean rust for 2015 will depend on how long it will take for the kudzu to leaf out – which will be delayed this year; and then how long it will take rust to begin to develop on the kudzu. 

Two new videos are out on soybean rust. The videos include highlights from numerous research and Extension projects carried out by land-grant university researchers from around the country involved in soybean rust research and monitoring efforts. 

The first video provides an overview of soybean rust, its impacts, its spread in the U.S. and how responding to this disease has changed the way researchers, Extension educators and farmers now approach soybean diseases in general.

The second video deals with efforts undertaken across the country to model, predict and forecast soybean rust through the use of “sentinel plots.”

Among its many accomplishments, the team has identified management strategies for soybean rust; made efforts to test and register fungicides for use in the U.S., giving soybean producers more options for controlling the disease; and established an extensive network initially of over 2,300 sentinel plots, helping farmers know more precisely where the disease is likely to occur and when and what types of fungicides to use.

Oomycetes fungicide

A new fungicide, which has activity towards Oomycetes, was labeled this month. INTEGO Solo is the product from Valent, but much of the initial field testing was done in Ohio.  The active ingredient ethaboxam provides similar or greater efficacy toward the diversity of water molds that attack soybean and corn seed and seedlings in Ohio. This will give an added benefit to many of the areas in the state that continue to struggle with replanting issues.

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