Response of selected nutrient elements in leaf tissues of sweet potato cv. ‘Bophelo’ to Nemafric-BL phytonematicide

Nemafric-BL phytonematicide is a potent plant-based nematicide which consistently suppress nematode population densities of root-knot (Meloidogyne species) nematodes on various crops, but with limited information on its effects on foliar nutrient elements in sweet potato. The objective of this study, therefore, was to investigate the effects of Nemafric-BL phytonematicide on accumulation of nutrient elements in leaf tissues of sweet potato cv. ‘Bophelo’ under greenhouse conditions in Limpopo Province, South Africa, during autumn (February-April) in 2021 and validated in 2022. The product was applied weekly at geometric concentrations, with mature leaves collected and prepared for analysis of nutrient elements at eight weeks. Seasonal interactions were not significant and therefore data were pooled (n = 70) and then subjected to the Curve-fitting Allelochemical Response Dose (CARD) algorithm computer model. Iron (R² = 0.86), K (0.91) and Na (0.82) versus Nemafric-BL phytonematicide each exhibited negative quadratic relations, whereas Zn (0.83) versus the product exhibited positive quadratic relations. In all test elements, the CARD-generated biological indices illustrated that the accumulation of elements was highly sensitive to the concentration of Nemafric-BL phytonematicide. In conclusion, in sweet potato production, the application of Nemafric-BL phytonematicide can inhibit (Fe, K) and stimulate (Zn) the accumulation of certain elements in leaf tissues of sweet potato cv. ‘Bophelo’.