Valorization of the Hydrolate Byproduct from the Industrial Extraction of Purple Essential Oil as a Source of Nematicidal Products.

The hydrolate byproduct resulting from the industrial essential oil extraction of Spanish purple garlic has been studied against the root-knot nematode by in vitro and in vivo bioassays. The essential oil, the hydrolate and its organic fraction caused high mortality of juveniles, suppressed egg hatch, and reduced nematode infection and reproduction on tomato plants. The nematicidal compounds of garlic oil, diallyl disulfide and diallyl trisulfide, were the major components of the hydrolate organic fraction. These findings have important implications for the development of new nematode control products based on garlic hydrolate compounds and highlight the recovery of waste from essential oils extraction, promoting a circular economy.