Files
Abstract
Ovipositional preference and reproduction of two thrips vectors of Tomato spotted wilt virus (TSWV) were investigated to determine plant host and TSWV effects on thrips population dynamics. The ovipositional preference between host plants (tomato and common chickweed (Stellaria media (L.) Vill.) with and without TSWV infection were also investigated with no choice and choice tests for whole plants in greenhouse cages and for leaf disks in growth chambers. Life tables of F. occidentalis and F. fusca were constructed from thrips feeding on leaf disks of different hosts (tomato and chickweed), plant age, temperature, photoperiod, and TSWV infection. In a greenhouse study, F. fusca oviposited five times more eggs per plant than F. occidentalis on both tomato and chickweed regardless of TSWV infection. F. fusca also oviposited significantly more eggs in chickweed than tomato and non-TSWV infected plants than TSWV-infected plants. In ovipositional preference studies in growth chamber, both F. fusca and F. occidentalis oviposited more eggs per leaf disks at temperature 25C (12L:12D) and at photoperiod 18L:6D (20C) in all four combinations of plant species and TSWV-infection. In partial life table parameter studies, both thrips species had no significant difference in net reproduction, generation time, and intrinsic growth rate, between two host plants with or without TSWV infection. Temperature and photoperiod significantly affected the three life table parameters. The intrinsic growth rates of F. occidentalis were negative at 20C and under while the intrinsic growth rates under 15C of F. fusca were projected to be negative. A temperaturedependence logistic population model for both species of thrips was calculated for both chickweed and tomato.