Cereal Rust Epidemiology Studies Using Roadside Trap Plots in the Southeastern United States. JOHN J. ROBERTS, Research Plant Pathologist, USDA-ARS, Departments of Plant Pathology and Crop and Soil Sciences, Georgia Station, University of Georgia, Griffin 30223. HOWELL A. FOWLER, JR., Agricultural Research Technician, USDA-ARS, Departments of Plant Pathology and Crop and Soil Sciences, Georgia Station, University of Georgia, Griffin 30223. Plant Dis. 78: 306-308. Accepted for publication 13 December 1993. Copyright This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1994. DOI: 10.1094/PD-78-0306.

Cereal rust trap plots were planted along a 2,687-km route using interstate and federal highways in the southeastern United States. The technique was developed and evaluated to study the oversummering and overwintering biology of four major cereal rusts: leaf and stem rusts of wheat, and crown and stem rusts of oats. The interstate highway system was selected to provide ease and speed of access for planting and monitoring, and for general safety reasons. Markers placed at 20-mi (32-km) intervals were selected for the trap plot sites to conform to established cereal rust survey techniques. Susceptible, well-adapted cultivars were preplanted in the greenhouse for subsequent transplanting at the sites and/or seeded directly to increase the likelihood of plot survival. The trials were conducted over a 7-yr period, 1986-1993, with 3 yr used to study oversummering (planted in July and sampled in November) and 4 yr to study overwintering biology during the normal growing season (planted in November and sampled in April). Severe droughts limited survival in 1986 and 1987. In 1988, several plots along the Gulf Coast were flooded and died. Planting and culturing techniques were modified each year to improve survival. Oversummering data indicated this method is useful for monitoring cereal rust survival during the summer, but plot survival rates under extreme stress may limit the effectiveness of the technique. Trials during 1990-1993 were promising, supplying both incidence and virulence data to supplement USDA-ARS Cereal Rust Laboratory annual surveys. The technique is not only effective for cereal rust research, but is also suitable for detecting other windborne pathogens, cereal and peanut viruses, and insect pests at a reasonable cost.

Keyword(s): Puccinia coronata, P. graminis, P. recondita