Study of chemical residues from Nemarioc-AL and Nemafric-BL phytonematicides in tomato fruit

Pesticide chemical residues in produce and products are a global concern in human and animal diets. Nemarioc-AL (a.i. cucurbitacin A) and Nemafric-BL (a.i. cucurbitacin B) phytonematicides serve as alternatives to synthetic nematicides in the management of root-knot nematodes (Meloidogyne spp.) in tomato (Solanum lycorpersicum) production. Cucurbitacins are the bitterest chemical compounds, and therefore, could affect fruit taste when used in tomato production to manage nematodes. The objective of this study was to determine whether tomato fruit where nematode numbers were managed using the two phytonematicides, contain cucurbitacin chemical residues. A field study using tomato cv. ‘Rodade’ was initiated, with untreated control, Nemarioc-AL and Nemafric-BL phytonematicides, laid out in randomised complete block design, with thirteen replications. Each phytonematicide at 3% was applied at a 17-day interval. At 110 days, after initiating the treatments, fruit were sampled and analysed for chemical residues using the isocratic elution Shimadzu HPLC Prominence with Shimadzu CTO-20A diode array detector. Cucurbitacin A and B residues were not detected in ‘Rodade’ fruit and therefore, the two phytonematicides were suitable for nematode management in tomato production under field conditions.