Horticultural and pathological aspects of Fusarium wilt management using grafted melons

The effect of Cucurbita and melon rootstocks on the horticultural and pathological performance of grafted Fusarium-susceptible melons was studied in four field experiments conducted in Fusarium-infested and Fusarium-free soils. The melon/melon combinations performed better than the melon/Cucurbita combinations regarding yield and disease control. In the 1999 experiment conducted in infested soil, Fusarium wilt symptoms were observed only in the nongrafted susceptible melons whereas all grafted combinations were symptom-free. In the 2000 experiment, nongrafted susceptible melons were totally wilted, whereas disease incidence in the melon/melon combinations and in one of the melon/Cucurbita combinations was low. The response of grafted plants to Fusarium wilt was also affected by the susceptibility of the scion. Among nongrafted melon cv. Ananas Ein Dor and those grafted onto Brava rootstock, 82% and 20%, were diseased, respectively, compared with only 36% and 0%, of the nongrafted and grafted 'Ofir' melons, respectively. Negligible quantities of fruit were harvested from the nongrafted plants grown in infested soil, whereas high and moderate yields were obtained from melons grafted onto melon and Cucurbita rootstocks, respectively. The yield of the nongrafted melons in Fusarium-free soils were similar to those of all the grafted plant combinations. Susceptible melon scions grafted onto resistant melon rootstocks were less colonized by F. oxysporum f. sp. melonis than the same melons grafted onto the Cucurbita rootstocks.