Abstract
Tylka, G.L., and S. K. Souhrada. 1997. Population densities of Heterodera glycines determined using global positioning technology. Journal of Nematology 29: (in press).
Growers are adopting global positioning system (GPS) technology for site specific crop management. To assess the utility of GPS technology for corn and soybean production, two 20.2-ha study areas were established in 1996 in large (>100 ha) fields, one planted with corn and the other with soybean. The study areas were divided into 0.2-ha cells, and pre-plant and post-harvest soil samples were collected from randomly selected sites which were located within each cell using a hand-held GPS unit. The soybean cyst nematode, Heterodera glycines, was found in all but two cells in both study areas. Initial H. glycines egg population densities in infested cells ranged from 50 to 29,000 eggs/100 cm3 soil, and cells with high initial H. glycines egg densities were aggregated in both study areas. During the growing season, detected H. glycines egg population densities increased as much as 300-fold in cells in the soybean study area, but densities generally decreased in the cells of the corn study area. Egg population densities will be correlated with other soil and plant variables measured in these cells.