Papaya seed extract for management of Radopholus similis on Anthurium

Anthurium cut flowers are an economically important ornamental crop in Hawai’i, but their production is threatened by the burrowing nematode, Radopholus similis, which reduces yield and increases production costs. This study evaluated the nematicidal potential of crude extract from ground papaya seed (PGS CE), a local agricultural by-product that contains glucosinolates that hydrolyze into benzyl isothiocyanate, active against R. similis. Greenhouse trials demonstrated that monthly drenches with 0.5 or 1.0% PGS CE significantly reduced R. similis population densities in both roots and cinder media, decreased root lesion severity, and increased leaf production without phytotoxicity or adverse effects on free-living bacterivorous nematodes. While 1.0% PGS CE slightly reduced plant biomass, 0.5% PGS CE improved plant growth and flower production. Regression analysis supported the link between nematode suppression and enhanced anthurium health. Thus, PGS CE presents a sustainable, locally available, and effective biofumigant for nematode management in anthurium, warranting further optimization and future field-scale validation.