BIOLOGICAL-CONTROL OF THE LEAFMINER LIRIOMYZA-BRYONIAE BY SEASONAL INOCULATIVE RELEASES OF DIGLYPHUS-ISAEA - SIMULATION OF A PARASITOID-HOST SYSTEM

A deterministic model was developed to simulate population growth of the agromyzid fly Liriomyza bryoniae and the parasitoid Diglyphus isaea. The model has two driving variables, ambient temperature and leaf nitrogen content of the tomato plant. Results of a glasshouse experiment were used to validate the model. The timing of successive generations of leafminers was simulated accurately over four generations. Population growth of leafminers was correctly simulated during the first two generations, but overestimated in the third generation. Mortality of leafminers due to parasitism was overestimated in the first generation after introduction of parasitoids: 73% instead of the observed 30%. A nearly 100% mortality of leafminers was correctly simulated in the second generation after introduction of parasitoids. Sensitivity analysis was performed for three types of variables: (1) driving variables, temperature and leaf nitrogen content; (2) parasitoid traits, searching efficiency and allocation of attacks to host feeding and oviposition, and (3) introduction strategies for biological control, timing, number of releases and number of parasitoids per release. Population growth was sensitive to temperature, leaf nitrogen content, searching efficiency of parasitoids and numbers of parasitoids released.