The potential of Lagenaria rootstock to confer resistance to the carmine spider mite, Tetranychus cinnabarinus (Acari : Tetranychidae) in Cucurbitaceae

Antibiosis and resistance of six Cucurbita and two Lagenaria accessions to the carmine spider mite, Tetranychus cinnabarinus Boisduval, were evaluated in the laboratory. Significant differences among accessions were observed three days after the inoculation of detached leaf discs. The Lagenaria acce ssions, Slawi and Sus, proved to be the most resistant to mites, with avera ge populations of mite eggs, 87 and 95%, respectively less than that of the susceptible C. pepo accession, Orangetti. The Cucurbita accessions, Tace, Brava, Tetsukabuto, Phoenix and TZ-148 had mite egg totals 4, 9, 13, 26 and 40%, respectively, less than those of accession Orangetti. The Sus accessi on of Lagenaria was resistant to T. cinnabarinus from the four-leaf stage u ntil fruit set in laboratory and field tests. Grafting the susceptible Brav a onto Sus rootstock increased the resistance of the scion to the same leve l as that of non-grafted Sus. Grafting the susceptible Cucumis melo Noy Yiz re'el on resistant or susceptible rootstocks of Cucurbita and Lagenaria acc essions did not affect its susceptibility to T. cinnabarinus. The results i ndicate that resistance to T. cinnabarinus can be transferred by grafting f rom Lagenaria stocks to Cucurbita scions but not in the opposite direction.