Induced response of tomato plants to injury by green and red strains of Tetranychus urticae

We studied the induced response of tomato plants to the green strain and th e red strain of the spider mite Tetranychus urticae. We focused on the olfa ctory response of the predatory mite Phytoseiulus persimilis to volatiles f rom T. urticae-infested tomato leaves in a Y-tube olfactometer. Tomato leav es attracted the predatory mites when slightly infested with the red strain , or moderately or heavily infested with the green strain. In contrast, nei ther leaves that were slightly infested with green-strain mites, nor leaves that were moderately or heavily infested with the red strain attracted the predators. We discuss the specific defensive responses of tomato plants to each of the two strains.