Pathogenicity of Meloidogyne incognita in bell pepper plants in Río Tocuyo, Lara State, Venezuela

Abstract

The relationship between a geometric series of eleven initial population densities (Pi) of Meloidogyne incognita, between 0 and 128 eggs and second stage juveniles (J2) per cm³ soil, and growth of pepper (Capsicum annuum L.) cv. Río Tocuyo was investigated in plastic pots containing 500 cm³ of sterilized sandy soil. Forty five days after inoculation, the growth variables such as total fresh weight (TFW) and top fresh weight (tFW), along with the final population density (Pf) of M. incognita were recorded. The growth values obtained were adjusted to the Seinhorst equation, y =  m + (1 – m)∙z^Pi-T. The tolerance limit (T) for both TFW and tFW was 0.10 hv+J2∙cm^-3 soil, thus indicating a very low level regarding those variables. The relative minimum yield (m) was 0, so 100 % growth reduction would be expected at Pi = 128 eggs + J2∙cm³ soil. Anatomical modifications observed in galled roots were similar to those induced by this root-knot nematode in other hosts. Giant cells in the central cylinder, disruption and compression of the vascular system were observed. The cultivar showed to be a material very susceptible to the pathogen.