Potential of grafted tomatoes to limit damage of aphids, whiteflies and nematodes in Uzbekistan: With special reference to plant volatiles

Tomato (Lycopersicum esculentum L.) is a major vegetable crop in Uzbekistan, where Macrosiphum euphorbiae (Aphidae) and Trialeurodes vaporariorum (Aleyrodidae) are devastating pests of this plant. The Mi gene for resistance to Meloidogyne incognita confers cross-resistance to foliar feeding insects, including M. euphorbiae and T. vaporariorum. Preferred Uzbek tomato cultivars, however, do not possess the Mi gene. Grafting local cultivar scions to tomato rootstocks with the Mi gene should control, M. incognita, but will foliar feeding insect resistance also be conferred to the scion? The objective of this research is to determine if the Mi insect resistance trait of cv. Anahu can be transferred to grafted cv. Rutgers in the presence and absence of M. incognita. Changes in phyllosphere (headspace) volatiles in response to grafting and feeding by M. euphorbiae, T. vaporariorum and M. incognita were quantified. Fewer than 30 volatiles were detected in the phyllosphere of cv. Rutgers plants infected with M. incognita; whereas, 44 were associated with non-infected plants. In both cases, the greatest emission rate was for ß-phellandrene, with the rate for the infected plants being significantly (P = 0.05) greater than that of non-infected plants. It is anticipated that grafting highly desirable tomato scion cultivars to rootstocks with pest resistance properties can have a major impact on tomato IPM practices in Uzbekistan.