Microplot Evaluation of Rootstocks for Control of Meloidogyne incognita on Grafted Tomato, Muskmelon, and Watermelon.

Microplot experiments were conducted over two years (four growing seasons) to evaluate Meloidogyne incognita resistance in rootstocks used for grafted tomato (Solanum lycopersicum), muskmelon (Cucumis melo), and watermelon (Citrullus lanatus). Three tomato rootstocks; 'TX301', 'Multifort', and 'Aloha', were tested in addition to the nongrafted scion, 'Florida-47'. Two muskmelon rootstocks; Cucumis metuliferus and 'Tetsukabuto' (Cucurbita maxima × Cucurbita moschata) were evaluated with the nongrafted scion 'Athena'. Two watermelon rootstocks included 'Emphasis', a lagenaria-type, and an interspecific squash hybrid 'StrongTosa', which were grafted to the scion 'TriX Palomar' and planted only in the second year. Microplots were infested with M. incognita eggs in September each year. Tomatoes were planted in September followed by melons in March. In both years of the study, M. incognita juveniles (J2) in soil were similar among all tomato rootstocks, but numbers in roots were higher in the nongrafted Florida 47 than in all grafted rootstocks. In muskmelon only C. metuliferus rootstock reduced galling in nematode infested soil. Tetsukabuto did not reduce numbers of M. incognita J2 in either soil or roots either year. There were no differences in nematode numbers, galling, or plant growth parameters among the watermelon rootstocks tested. The use of resistant rootstocks has great potential for improving nematode control in the absence of soil fumigants.