Estimation of Pelargonium sidoides root damage by Meloidogyne spp.

Abstract

Pelargonium sidoides is a medicinal plant species indigenous to Southern Africa. Its roots are used for treating a variety of ailments in man and livestock. It is in great demand by local users and international pharmaceutical producers. Root-knot nematodes, Meloidogyne species, penetrate into the roots of plants in search of food and for reproduction locations, resulting in the formation of galls. They affect the plant's ability to absorb water and nutrients. P. sidoides plants, grown as part of a fertilizer trial, showed susceptibility to root-knot nematodes. Fifteen plots were replicated three times in a randomized complete block design with different levels of nitrogen, phosphorus and potassium. Ten plants per treatment were harvested eight months after planting, with the aim of developing a root-knot nematode rating chart. Each root system was assessed and ranked on a class of 0 to 10, with 0 representing no galls, 5 representing 50% infestation and 10 representing severe infestation. Meloidogyne incognita and Meloidogyne javanica were identified in the root samples. The sampled roots showed more than 50% infestation. It is recommended that the soil should be analyzed and treated accordingly, before planting P. sidoides to avoid root damage by root-knot nematodes.