Progress 01/01/03 to 09/30/05
Outputs
Inference zones established within the state in 2004 were used in the current year as a tool to enhance the soybean rust surveillance program. Factors considered for zone delineation included continuity of crops and ecosystems, but climatological data (air temperature, humidity, and rainfall) were used as the primary criteria to establish zones. Soybeans and a Kudzu patch were monitored early in the 2005 growing season for symptoms of soybean rust and other disease symptoms. As in 2004, software developed by the University of Nebraska, J.D. Edwards Honors Program through funding provided by U.S.D.A. APHIS was used to assist in surveying and to potentially track collected samples. This software, Integrated Survey Information System, is a data collection tool which functions on hand held computers. It is designed to capture global positioning coordinates, and to facilitate data entry to document and track new or exotic plant diseases and pests. Field data entered into the
hand-help computer was transferred to an office-based personal computer database. As the 2005 growing season progressed, a sentinel plot monitoring program was deployed. Sentinel monitoring plots were established at 48 sites throughout the soybean production areas of Nebraska. Plots were located from the southern to northern borders and from the eastern border to the western limit of soybean production within the state. Within this geographic area, plots were evenly distributed. Most sentinel plots were planted within commercial soybean production fields and were a minimum of 1200 square feet in size. All plots were planted to the same soybean variety (Asgrow 1903). In all cases, sentinel plots were planted earlier than commercial bean varieties. Because of heavy rain in a few locations, sentinel plots required replanting. A team of 31 cooperators comprised of County Extension Faculty and commercial pest consultants was assembled to scout the sentinel plots. A training manual was
developed to familiarize the cooperators with the statewide sentinel plot program and to provide information detailing the protocol. Cooperators participated in a daylong training session where they were trained to spot soybean rust symptoms and distinguish them from other soybean rust foliar diseases. Following soybean emergence, cooperators monitored plants weekly within sentinel plots. Within each plot, cooperators looked at 150 leaves for rust symptoms. The protocol used was identical to the USDA and NCSRP Protocol for Soybean Rust Sentinel Sites. Collected data was entered in the USDA APHIS Scout Web Site. Soybean rust was not detected.
Impacts
Early detection of soybean rust in Nebraska will reduce the economic loss due to this disease by effectively timing a fungicide application. In addition, the sentinel plot system will allow for confirmation of no disease present and reduce unneeded fungicide applications.
Publications
- Watson, S., Giesler, L.J. and Hunt, T. 2005. Real-time soybean disease and insect pest information via the Nebraska Crop Surveillance Network. 2005. Phytopathology 95:S109.
- Giesler, L.J. and Weissling, T.J. 2005. Fungicides to Manage Soybean Rust: What are the Product Differences? NF05-634. University of Nebraska-Lincoln Extension.
- Giesler, L.J. 2005. Soybean Rust: How Great is the Threat for Nebraska? NF05-633. University of Nebraska-Lincoln Extension.
- Giesler, L.J., Wilson, J.A. and Rees, J.M. 2005. Soybean Rust Fungicide Use Guidelines for Nebraska. NF05-652. University of Nebraska-Lincoln Extension.
|
Progress 10/01/03 to 09/30/04
Outputs
Four inference zones were established within the state as a tool to enhance the soybean rust surveillance program. Several factors were considered for zone delineation such as continuity of crops and ecosystems, but climatological data (air temperature, humidity, and rainfall) were used as the primary criteria to establish zones. Within each zone, at least 2 surveillance sites were established for a total of ten sites distributed across the eastern half of the state. A training manual was developed to familiarize cooperators with the statewide soybean surveillance program and to provide comprehensive information detailing all plant disease and arthropod pests within or threatening the state. Cooperators participated in a daylong training session. Following soybean emergence, cooperators monitored plants weekly within surveillance sites and recorded disease incidence and severity, arthropod pest populations, and growth stage. In addition, weather data near or at each
site was gathered. Samples of plants with unknown disease symptoms were mailed to the diagnostics laboratory at the University of Nebraska for identification. No soybean rust was identified, but several other diseases were found. All data has been entered into a database. The visual interface for this database is still under development. Additional sites were also monitored throughout the summer. From July - September, 150 soybean fields in 32 counties were surveyed for diseases and arthropod pests. One of the primary alternative hosts for soybean rust, kudzu, was sought but not found within the state. Samples were taken when the surveyor was unsure of identification. Software developed by the University of Nebraska, J.D. Edwards Honors Program through funding provided by U.S.D.A. APHIS was used to assist in surveying and in tracking collected samples. This software, Integrated Survey Information System, is a data collection tool which functions on hand held computers. It is designed
to capture global positioning coordinates, and to facilitate data entry to document and track new or exotic plant diseases and pests. Field data entered into the hand-help computer was transferred to an office-based personal computer database. Soybean rust was not found. However, by monitoring brown spot (Septoria glycines), the survey system proved valuable in providing accurate assessments of disease spread. Although the data is still being analyzed, differences in delineated zones appear to accurately reflect differences in the incidence of soybean diseases and arthropod pest populations. In addition, a soybean disease rarely seen in Nebraska, frogeye leaf spot (Cercospora sojina), was found in one field. This discovery strongly demonstrates the ability of the Nebraska surveillance network to locate and map new disease outbreak foci. Two extension publications were produced to emphasize the differences between currently occurring soybean diseases and the exotic soybean rust. In
addition, materials developed for the cooperator-training handbook are currently being integrated into a comprehensive web site detailing the Nebraska soybean surveillance network.
Impacts
The arrival of soybean rust to the United States soybean production areas could cause large crop and economic losses to growers. Recent analysis estimates that losses for the first year of establishment of soybean rust in the U.S. will range from $640 million to $1.3 billion. Early detection of soybean rust in Nebraska could reduce the economic loss potential due to this disease by signaling the need for fungicide application. Rapid delineation of outbreak areas would have additional benefits in helping to limit disease spread.
Publications
- Giesler, L.J. and Weissling, T.J. 2004. Bacterial Diseases of Soybean. G04-1544. Nebraska Cooperative Extension.
- Giesler, L.J. and Weissling, T.J. 2004. Brown Spot of Soybean. G04-1545-A. Nebraska Cooperative Extension.
|
|