Field trial with root-knot nematodes
A Good Experimental Practice-compliant trial was performed between September 2019 and February 2020 in a naturally nematode-infested greenhouse in Ispica (Sicily, Italy; coordinates 36.723783°N 14.968736°E) by SATA s.r.l (Quargernata, Italy). Treatments were arranged in a randomized complete block design with four 22 m2 plots per treatment (22 tomato plants per plot,S. lycopersicum ‘Ciringuito F1’, planted September 9th 2019). The pre-trial nematode population was assessed as in Hallmann & Viaene (2013). PA was applied using a handheld sprayer (300 µM PA, 0.1% (v/v) DMSO and 0.1% (v/v) Tween 20) three times: eight and one days before transplanting and two weeks after transplanting. The nematicide Cedroz (Eastman), containing geraniol (121 g l-1) and thymol (41 g l-1), was used as a reference treatment and was applied per the manufacturer’s guidelines (9 l ha-1 total, 6 fortnightly applications). Starting in October 2019, four (intermediate assessments) or ten (final assessment) tomato plants per plot were uprooted and evaluated for vigor, phytotoxicity and galling severity on the Zeck scale (Zeck 1971). Yield was evaluated by picking and weighing ripe fruits weekly between December 2019 and February 2019.