Studies on the Varietal Difference in Injury Caused by Thrips palmi in Chrysanthemum

3. Relationship between Infested Part, Density and Injury

Abstract

The occurrence and injury level of T. palmi on each of five varieties of chrysanthemum were compared to clarity whether there were varietal differences between attacked parts and the population density of T. palmi. There was no difference in attacked parts and the population density of T. palmi between varieties. Most adults aggregated to the growing point before flower differentiation, and dispersed to other plant parts thereafter. Injury was caused by feeding on pre-leafing leaves around the growing tips.