Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
Delmarva watermelon growers have challenges from two soil borne pests, Fusarium Wilt, and Southern Root Knot nematodes. Current management practices include long rotations with non-hosts, soil applied fungicides and soil applied nematicides.
There is now another tool that growers can use to manage these pests where both pathogens are present — grafting watermelon plants onto “Carolina Strongback’ rootstock.
Carolina Strongback was bred by USDA-ARS scientists and was tested by Clemson University researchers in South Carolina. It is a cross between several wild watermelon citron lines and was released in 2019. According to the USDA-ARS “Selected for its grafting qualities and seed production, Carolina Strongback material can be used by seed companies, vegetable grafting companies and watermelon growers as a rootstock for growing susceptible watermelon cultivars in soils infested by the watermelon Fusarium wilt pathogen (races 1 and 2) and (southern) root-knot nematodes”.
This rootstock was used in 2020 with grafted seedless watermelons in many locations and performed well. We expect increased availability in the future.
Fascination grafted onto Carolina Strongback rootstock