| Department of Agronomy Newsletter | Summer 1999 |
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Predicting the occurrence of blast disease of perennial ryegrass The turfgrass industry is a billion dollar business in Pennsylvania. Diseases such as gray leaf spot, also known as blast disease, pose significant challenges to the industry's goal of producing and maintaining high quality turf for golf courses, athletic fields, lawns, and sod. Perennial ryegrass, a prime target for blast disease, is an important component of golf course fairways in western and eastern Pennsylvania because it germinates quickly and has upright growth. "Blast disease of perennial ryegrass is a newly emerging disease in Pennsylvania and the northeast U.S.," explains Dr. Wakar Uddin, assistant professor of Plant Pathology. Uddin is affiliated with the Turfgrass Research Center, a multidisciplinary center directed by agronomy faculty and involving researchers from the departments of agronomy, plant pathology, |
Making sense of yield monitors About three years ago, a team of department faculty and staff began working on the application of precision agriculture techniques in Pennsylvania. The goal is to determine the agronomic utility of yield monitoring and mapping and soil nutrient mapping given Pennsylvania's small average field size and highly variable soil. "Farmers get lots of input in the form of ads and testimonials about products they should use on their farms," says Dr. Greg Roth, associate professor of Agronomy. "But those ads are not always backed up by research. With our project, we're trying to help farmers learn how to use yield monitors as a tool to do their own product research." A yield monitor attaches to the combine and works by |
measuring the force with which shelled grain hits a stainless steel sensor plate inside the combine. This force, along with the moisture content of the grain, can be calibrated to the yield. The research team first tested the accuracy of a yield monitor (cost ~ $3500) in hybrid strip tests. They determined that the use of a yield monitor is effective for comparing the yields of field-length strips of various commercial hybrids. In the first year of the study, the accuracy of the yield monitor was good, but it had difficulty with high grain moisture contents. After an upgrade of software and hardware, the accuracy in the second year increased significantly. Roth's crew obtained yields with + 5 to 8 percent error in these 1/3-acre strips. The average error was 0.3 percent. This means that approximately 66 percent of the time the yield monitor calculation was within 2.6 percent of the actual yield, |
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horticulture, and entomology. "Blast disease is becoming a problem in the Midwest and the South." The disease first appeared in Pennsylvania in 1991 in the southeast region. Major outbreaks occurred in summer 1998. Some golf courses had up to 95 percent loss of turf on ryegrass fairways," Uddin says. The disease was first spotted in western Pennsylvania last year. In the Northeast, outbreaks also occurred in New Jersey, Maryland, Virginia, and West Virginia. Besides affecting perennial ryegrass, the fungus Pyricularia grisea |
A weigh wagon is used to
calibrate the yield monitor on the combine.
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