Effect of Weather Patterns on the Incidence of Asian Soybean Rust in Georgia

Summary

Weather plays a significant role in the development and spread of Asian Soybean Rust (ASR). The degree of severity of rust infections has been proven to be highly dependent on rainfall and the number of rainy or cloudy days.

Situation

Asian soybean rust is a foliar fungal disease caused by Phakopsora pachyrhizi. It is an aggressive disease capable of causing defoliation and significant yield loss in soybean. In the United States, the risk of soybean rust moving from the south to the north depends on the occurrence of soybean rust during the spring and early summer which determines the amount of spore movement northward. The United States Department of Agriculture established a soybean rust surveillance, information, and education program to enhance the ability of domestic producers to respond effectively to rust establishment. In Georgia, ASR monitoring efforts led by the University of Georgia (UGA) include the establishment of sentinel plots and spore traps in several counties across the state. There is a need to monitor environmental conditions around or near sentinel plots in addition to monitoring spore traps and ASR infection of soybean. Given the strong interaction between environmental conditions, infection by spores of soybean rust, and spread of this disease in the soybean crop, it is of critical importance to compliment current soybean rust detection efforts with additional weather monitoring as a predictive tool to detect early disease spread.

Response

To address the infection and yield problems caused by the disease, our research is investigating the relationship between weather parameters and the incidence of Asian Soybean Rust. Our goal is to help improve the understanding of the impact of weather variables such as temperature, relative humidity and rainfall on ASR, and how these factors could help explain infection initiation, progression of soybean rust during the growing season and variation in the level of disease incidence from one season to the next. In order to monitor the progression of soybean rust, field data were collected annually across sentinel plots established in several locations in Georgia. We collected and analyzed data from Georgia Automated Environmental Monitoring Network (AEMN) weather stations where soybean sentinel plots have been established. The accumulated rust infection day was calculated based on known favorable environmental conditions for disease development.

Impact

The results showed a positive correlation between the accumulated rust infection days and the incidence of ASR in three soybean cultivars evaluated. Establishing baseline information on the environmental conditions that contribute to the movement of ASR spores and subsequent infection in soybean will allow researchers and extension specialists to better understand the epidemiology of soybean rust. Furthermore, the results from this project could potentially pave the way in designing an effective early-warning and disease forecasting system based not only on early detection but also the understanding of conditions favorable and unfavorable to infection and spread of ASR. Consequently, the project will benefit soybean growers in Georgia since they will be better informed and prepared in controlling soybean rust.

State Issue

Agricultural Profitability and Sustainability

Details

  • Year: 2008
  • Geographic Scope: State
  • County: Spalding
  • Program Areas:
    • Agriculture & Natural Resources

Author

    Paz, Joel O.

Collaborator(s)

CAES Collaborator(s)

  • Hoogenboom, Gerrit
  • Kemerait, Robert C
  • Olatinwo, Rabiu O.
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Research Impact