July 5, 2006 | By: Laura Skillman

University of Kentucky crop physiologist Saratha Kumudini is leading an international team of scientists developing a soybean rust yield loss prediction tool for farmers.

The study’s objective is to predict yield loss from soybean rust at various reproductive stages. The yield loss prediction will be used to develop an interactive software tool that would determine the farmer’s yield potential and the predicted yield loss if rust should defoliate the crop. The model would allow a producer to weigh the potential yield loss against the cost of fungicide applications to make sound management decisions.

This risk management tool should improve producers’ net economic return and guard against unnecessary fungicide applications that can impact the environment and increase the risk of developing fungicide resistance, Kumudini said.

“We envision them getting information from the Cooperative Extension Service through the sentinel plot network when rust may be in the area. They can then use this tool to determine the economic feasibility of spraying or not spraying a fungicide on their fields,” she said.

The project was awarded a grant from the U.S. Risk Management Agency, a division of the U.S. Department of Agriculture and the Southern Soybean Research Program. Kumudini is the principal investigator.

“The project involves a multidisciplinary team of physiologists, pathologists, agronomists and extension specialists working together,” she said.

She and several UK colleagues have a collaborative agreement with Claudia Godoy, a plant pathologist with Brazil's national agriculture department Embrapa. Nationally, the team includes co-investigator Jim Board at Louisiana State University and collaborator John Mueller at Clemson University. UK project members are plant pathologist Don Hershman, grains crop specialist Chad Lee and agronomist Joe Omielan. 

“The collaborative nature of this project has allowed us to hit the ground running,” Kumudini said. “We got the funding in September 2005 and planted soybeans in November in Brazil and already have the first year’s data from Brazil.” 

The first U.S. plantings were done this spring from Kentucky to Louisiana, enabling researchers to collect data from a number of different soybean maturity groups. It also means a large part of the country that is considered the hot spot for soybean rust is being covered. The project will mimic the impact of rust to have controlled defoliation.

Kumudini said the more information they can collect on U.S. soybean varieties under U.S. conditions, the more accurately the prediction model will reflect what will happen when soybean rust impacts a field.

Through his Extension work, Hershman spends a great deal of time working with farmers on soybean rust. He is coordinator of the sentinel plot network for Kentucky and the southern United States and is a co-investigator on this project. 

“We get a lot of questions from farmers on should they or should they not spray, and we kind of have these generalities but they are not hard and fast rules,” Hershman said. “A lot of things we are assuming but don’t have the research information to back it up. So, this will be a very valuable tool.”

Kumudini said they will begin testing the calculator with some growers in 2007, then, depending on how well it works; she hopes it will be available to all growers in 2009.

“By creating a mathematical model that predicts yield loss due to soybean rust, we hope to provide a decision aid tool that protects farmers from large losses in either yield or economics,” she said.

Information about the project and updates on its progress can be found here. Under the resources link on the Web site is a recently translated pamphlet containing soybean rust management information from Embrapa, Brazil’s federal agricultural agency. While the information is Brazilian data for Brazilian conditions, plant pathologists at UK and Clemson say it provides useful information for U.S. growers until independent data from the United States can be developed. 

Hershman said knowing what is being recommended and what is working in Brazil has some merit.

“It can confirm what we are recommending,” he said. “I wouldn’t recommend a farmer use the information in a vacuum but as one piece of information to help them evaluate their options.”



Saratha Kumudini, 859-257- 5020, ext. 80752, Don Hershman, 270-365-7541, ext. 215