The plant parasitic root-knot nematodes Meloidogyne spp. are a devastating threat to agriculture. The urgent need to search for alternative root-knot nematode control methods that are less environmentally toxic is a demanding challenge to secure the increasing global food demand. Therefore, we combined chemical and biological control strategies to evaluate their management potential on Meloidogyne incognita infested tomatoes. To determine the combined effect of the nematicides Velum and Purpureocillium lilacinum strain 251 formulated as wettable granulate (BioAct WG), we evaluated tomato yield parameters, gall index, soil and root nematode populations. Velum is a chemical nematicide with fluopyram as its active ingredient and BioAct is a biological nematicide based on the egg pathogenic fungus Purpureocillium lilacinum (strain 251). As a single treatment, the nematicide Velum showed better M. incognita reduction at-planting, while BioAct controlled the nematode population throughout the growing season. Greenhouse experiments in two consecutive years, showed that by combining the two nematicides, the M. incognita controlling effect was enhanced and the tomato yield increased compared to single nematicide treatments. The controlling effect of P. lilacinum was lower when M. incognita population increased, presumably based on its limiting ability to parasitize the increasing numbers of nematode eggs. To conclude, we have shown that combining chemical and biological nematicides can successfully control the root-knot nematode M. incognita and increase yields. Velum downregulated the nematode population at-planting and reinforced the biological efficacy of P. lilacinum throughout the growing season.
