A Stage-Structured Model of Scaphoideus titanus in Vineyards

We present a population model of the insect Scaphoideus titanus Ball, the leafhopper vector of Flavescence Dore´e phytoplasma in Vitis vinifera L. The model accounted for the stagedependent S. titanus life cycle rates and timing, and vineyard settings such as surface area, plant density, and sampling characteristics. The model parameters were estimated against 13 independent cases of population counting in both laboratory and Þeld conditions, and returned a correlation coefÞcient in the range 86.4 to 99.1% with residuals in the range 3.5 to 26.3%. A statistical parametric analysis showed that the standard deviation of life cycle rates generally varied more than the one resulting from timing parameters. However, a stochastic sensitivity analysis showed that S. titanus dynamics were more susceptible to variations in timing than rate parameters. Analysis of scenarios of insecticide suppression efÞciency and timing showed that S. titanus presence could be optimally controlled by a combination of suppression efÞciency and timing. These results were instrumental to understand in which speciÞc aspect of S. titanus life cycle could pest management operations be most effective to reduce S. titanus presence in vineyards, and possibly reduce the risk of Flavescence phytoplasma spread.