Thrips responses to plant odours

Thrips responses to plant odour compounds were assessed using a Y-tube olfactometer. Several compounds were attractive to adult Frankliniella occidentalis females, since the majority walked towards the odour source. Some odours that were attractive for western flower thrips appeared to be non-attractive for Thrips tabaci and visa versa. Chrysanthemum buds or flowers that were used as an odour source in the olfactometer elicited no positive response from western flower thrips. In wind tunnel experiments, where thrips could use both olfaction and vision, thrips preferred to settle on open chrysanthemum flowers when buds were the alternative. When flowers and buds were covered with a perforated hood, preventing visual orientation, there was no difference in numbers of thrips settling on buds and open flowers. This indicates that colour is a dominant factor for thrips orientation towards flowers