Hotline, web site help growers make timely treatment decisions

By Tracy Sayler

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Prairie Grains is the official publication of
the Minnesota
Association of
Wheat Growers,
North Dakota Grain Growers Association,
South Dakota Wheat, Inc., and the Minnesota Barley Growers Association.

The forecasting information can be found on the Internet at the web site: www.ag.ndsu.nodak.edu/cropdisease. The information is also summarized in recorded updates that wheat producers can access toll-free by phone at 1-888-248-7357.

NDSU plant pathologist Leonard Francl is project manager of the wheat disease forecasting system, which measures fungal spores, wheat growth development, and weather conditions to pinpoint, in near-real time, the potential for scab, tan spot, and Septoria blotch disease infections in wheat.

The system uses weather data obtained from the North Dakota Agricultural Weather Network (NDAWN). Fungal spore samplers are located near 17 NDAWN weather stations across the Red River Valley and the northern tier of North Dakota. The sampling devices collect pathogen spores from the air and rain. Spore counts and growing degree days are added to weather information, and the data is then analyzed by three computer models to determine whether an infection period has occurred for each of the three diseases.

NDSU plant pathologist Len Francl (at right) shows John Kostishack, executive director of the St. Paul, MN-based Otto Bremer Foundation, some of the wheat disease spore sampling equipment that Francl and other researchers are using to operate a wheat disease forecasting system to help wheat producers with disease management decisions. The forecasting equipment, located at 17 locations across the Red River Valley and the northern tier of North Dakota, is funded in part by the Otto Bremer Foundation, a private, charitable trust. "The Otto Bremer Foundation’s support of this project is a good example of how wheat checkoff dollars are leveraged with other sources to fund research that is valuable to wheat producers," says David Torgerson, executive director of the Minnesota Wheat Research and Promotion Council, which is helping to fund the wheat disease forecasting system through the Minnesota wheat checkoff. The MWRPC ranked the monitoring of spores that cause scab as its highest research funding priority for 1999. Photo: Tracy Sayler

Francl says the computer models classify whether or not a given 24-hour period was favorable for infection. "Infection happens when an infectious pathogen contacts a susceptible plant in a suitable environment. Multiply this event millions of times and you have the beginnings of a plant disease epidemic in a field," says Francl.

To find out if the previous day contained an infection period, the models use hourly weather data sent from NDAWN to NDSU every morning, and summarized from noon to noon. Noon, rather than midnight, was chosen as a cut-off so that the dew period, critical for disease development, is considered in its entirety, says Francl.

The web site, and the toll-free number, give daily weather summaries, including humidity, temperature, and moisture. The presence of disease spore counts are given in three alert levels, using the three traffic-light colors of green, yellow, and red: Green means no spores were detected in a particular area; yellow, a few spores have been found; and red, a large amount of spores were detected.

For scab to develop, Francl says the spores that cause the disease must germinate and infect wheat at flowering, in order for the pathogen to damage the crop. High humidity, rain and dew affect infection the most, while cool temperatures tend to limit fungal growth. These conditions are reported in the system to help producers decide whether infection is likely in their particular area, says Francl.

Along with the forecasts, the web site includes information on disease symptoms, and the window for timely treatments, as well as factors to help weigh whether treatment is necessary.

The Minnesota Wheat Research and Promotion Council ranked the monitoring of spores that cause scab as its highest research funding priority for 1999. The MWRPC is helping to fund the wheat disease forecasting system through the Minnesota wheat checkoff. North Dakota ag research and federal research funding, as well as private-source funding from the Otto Bremer Foundation and the Dakota Growers’ Pasta Co., are also supporting the wheat disease forecasting system.

APS web site features Fusarium
The American Phytopathological Society, based on St. Paul, MN, spot-
lighted Fusarium head blight on its web site (www.scisoc.org) during the month of May. The comprehensive feature (still posted) includes information compiled by Robert Stack, a member of APS and a North Dakota State University plant pathologist. Other literature on scab was also included, as well as links to other online scab resources.

NDSU Wheat Disease Forecasting System
Toll free by Phone 1-888-248-7357

Or Online at:
www.ag.ndsu.nodak.edu/cropdisease

Research and information funded in part by the Minnesota Wheat Checkoff