Forecasting System Valuable for Predicting Favorable Disease Conditions

With Fusarium Head Blight incidence and severity being so dependent upon moisture conditions, any tool which will help growers predict the likelihood of favorable disease conditions is a blessing.

For North Dakota and western Minnesota grain producers, that blessing comes in the form of NDSU’s disease forecasting system. Available on the web (www.ag.ndsu.nodak.edu/cropdis-ease), the system’s information also is available via summarized, regularly updated, recorded toll-free telephone messages (1-888-248-7357).

The forecasting system, supported in part by the Minnesota wheat checkoff, tracks fungal spores, wheat growth development and weather conditions to pinpoint, in near real-time, the potential for FHB (scab), leaf rust, tan spot and Septoria blotch disease infections.

The system’s manager, NDSU plant pathologist Len Francl, reports that in 2001, spore counts of the fungus that causes FHB were mostly low across the region during the critical flower period.  The exception was very high mid-July counts in north central North Dakota, where FHB severity was greatest. Of the diseases predicted last year, infection periods were most numerous for tan spot. Though fewer Stagonospora leaf blotch infection periods were predicted, the nature of that disease (higher number of infections per period and its spreading blotch rather than a small spot) meant it caused more leaf damage. Leaf rust generally came in late and was a problem only with certain cultivars.

The disease forecasting system models will be activated in May and forecasts will then be available for 47 locations in Minnesota, North Dakota, and South Dakota. Anticipated improvements this year are three more Fusarium spore count stations, computerized forecats of FHB in all locations and regional maps of each disease forecasted.

Marcia McMullen views the disease forecasting system as a very valuable tool. “To date, scab forecasting has relied on sport counts,” she says. “But further refinement of infection models for scab, based on weather events, will ultimately give growers even better tools for fungicide decisions.”

SDSU Introduces FHB Forecasting Model
South Dakota State University will also have a FHB forecasting model in place in the 2002 growing season.

SDSU Extension Plant Pathologist Marty Draper says the forecasting model will rely on weather information gathered partly with the help of cooperators working with SDSU. The model will use such factors as temperature extremes and the period of leaf wetness or residue wetness to come up with a risk assessment for the area.

Initially SDSU plans to gather information in the Britton and Aberdeen-Groton areas, and possibly in the Huron, Onida and Selby areas.

Draper says producers will have to apply the information from the forecasting model to their particular situation. The risk will be different for fields that are flowering compared to fields that are not flowering, for example, and fields with heavy residue from corn or wheat also carry higher risk.  “This will not make a (treatment) decision for growers,” Draper says. “What we hope this will do is help producers understand the risk and give them more information to make a decision.”

South Dakota producers lost less than 1% of their crop to FHB last year, although some individual fields had damage of up to 50%.

For more information, see the web site, http://plantsci.sdstate.edu/planthealth/