SOPRA: A FORECASTING TOOL FOR INSECT PESTS IN APPLE ORCHARDS

Abstract

SOPRA, a phenology-model based forecasting tool for insect pests has been developed with the objective to optimize the timing of monitoring, management and control measures in Swiss apple orchards. Applying the time-varying distributed delay approach, air and soil temperature driven phenology-models were developed for three major insect pests of apple: The rosy apple aphid (Dysaphis plantaginea) the apple sawfly (Hoplocampa testudinea) and the smaller fruit tortrix (Grapholitha lobarzewskii). The models were parameterized using the relationships between temperature and stage specific developmental rates established under controlled conditions. For validation, model predictions were compared with independent field observations from several years, on the hatching of winter eggs in the case of the rosy apple aphid, and the emergence of adults in the case of the apple sawfly and the smaller fruit tortrix. For additional pests a routine was implemented to compute temperature sums for user defined temperature thresholds. The user interface was designed as a common MS-Windows@ application in order to facilitate the simultaneous use of the different models, and to standardize the weather data input, and numerical and graphical output. SOPRA predicts the age structure of rosy apple aphid, apple sawfly and smaller fruit tortrix populations, computes temperature sums for other pests and announces crucial events for management activities. Provided air and soil temperature data are available, SOPRA can be applied as a decision support system for insect pest management on a local and a regional scale.