Management of rootknot nematodes on Solanum macrocarpon using botanicals in Benin

Abstract

Root-knot nematode (RKN), Meloidogyne spp. is an economically important pest of the traditional leafy vegetable, Solanum macrocarpon L., in Benin. In the search for IPM options, the effect of 5, 20, 35 and 50 g of dried skin peels of cassava storage roots (CP) and orange fruits (OP) each on incidence and damage severity of RKNs and biomass of S. macrocarpon was compared to that of 1, 2, 3 and 4 mg of commercially available fungal nematicide Paecilomyces lilacinus (Pl) and the chemical nematicide Rugby10 applied at 0.4 gpotted S. macrocarpon. In the field experiment CP and OP applied at 840 g and 1200 g1.4 m x 1 m bed; Pl at 75 g and 96 gbed and Rugby10 at 12 gbed. The botanicals, Pl and Rugby10 were mulched into soil, which was later planted with S. macrocarpon seedlings from nematode-free nurseries. In the potted plant experiment, pots were each inoculated with 1500 juveniles of RKNs. In the study, the botanicals showed promise against RKNs, especially when applied at highest doses. In pots, OP applied at 50 gpot and Rugby10 reduced percentage roots with galls significantly more than did control treatment. CP and OP at 50 gpot were as efficient as Pl and Rugby10 in reducing nematode population density. CP at 50 gpot had higher biomass than potted plants with Pl at dose inferior to 4 mgpot, Rugby10 and control plants. In field, OP, CP and Pl when applied at highest doses significantly reduced percentage roots with galls and nematode population density and increased plant biomass as compared to control.