Site-specific integrated pest management for high-value crops: impact on potato pest management

Site-specific agriculture optimizes agricultural inputs by varying application rates to match within-field requirements. Two years of trials were conducted in rotated commercial potato fields to compare traditional whole-field integrated pest management with site-specific management for Colorado potato beetle, Leptinotarsa decemlineata (Say), green peach aphid, Myzus persicae (Sulzer), and potato leafhopper, Empoasca fabae (Harris). Additionally, the spatial dynamics of Colorado potato beetle populations subjected to whole-field integrated pest management were studied. Colorado potato beetle infestations mostly remained near field edges throughout the season. Highest densities for each life stage remained near the locations of the initial colonizing adults. Even if management thresholds were as low as the 3rd density decile, between 60 and 95% of the field area could be left untreated when the mean density exceeded the threshold. Site-specific management reduced insecticide inputs for the green peach aphid but not for potato leafhopper. Initial Colorado potato beetle colonization pressure, measured as egg mass density approximately 7 d after crop emergence, was a significant covariable in determining season-long insecticide requirements. Analysis of covariance demonstrated that after accounting for this variable, site-specific management significantly reduced insecticide inputs compared with whole-field integrated pest management. Cumulative season-long Colorado potato beetle insecticide savings of 30-40% across a broad range of colonization pressures were observed