Use of extracts of Tithonia diversifolia and Gymnanthemum amygdalinum in the control of Meloidogyne incognita

Abstract

Meloidogyne incognita (kofoid & white) chitwood. is one of the species of phytoparasitic nematodes that causes the most losses to world agriculture. The aim of the study was to evaluate the effect of the aqueous extracts of Tithonia diversifolia and Gymnanthemum amygdalinum on the hatching of juveniles of M. incognita and their effect on tomato plants. The extracts were obtained by dynamic infusion. For the in vitro test, microtubes containing extract and the suspension of nematode eggs were prepared. After 15 days of incubation, the number of eggs and mobile and immobile juveniles were evaluated to calculate hatch inhibition. The results demonstrated that all the tested extracts had an inhibitory effect on the hatching of M. incognita when compared to the conventional nematicide. In the in vivo test, tomato plants of the cultivar Santa Cruz Kada, aged three weeks, were inoculated with a suspension with 2000 eggs of M. incognita and subjected to application of the extracts. After 60 days, the reproduction factor (FR) and the number of galls/grams of root (NGGR) were evaluated, as well as the weight of the fresh root material (PMFR) and the aerial part of the plants (PFPA). The best results were observed in plants treated with the extract of the leaves and dry stem of T. diversifolia.