A Feeding Deterrent for Thrips palmi KARNY (Thysanoptera: Thripidae) Found in Tomato Leaves: Isolation and Identification.

Abstract

Thrips palmi is polyphagous but does not attack tomatoes. A crystalline compound possessing strong antifeedant activity for this insect species was isolated from tomato leaves using methanol extraction, water/butanol partition, silica gel chromatography and preparative high-performance liquid chromatography. The compound was identified as the steroidal glycoalkaloid alpha-tomatine. It is concluded that the immunity of tomato plants to T. palmi is explained solely by the occurrence of alpha-tomatine, because T. palmi does not use airborne information (attractants/repellents) to avoid tomato leaves, and tomato leaves apparently provide the required phagostimulants and nutrients.