Nematicidal activity of powder and extracts of Melia azedarach fruits against Meloidogyne incognita

Pulverised lyophilised (dehydrated) Melia azedarach (Meliaceae) fruits (PMF) were tested in a dose–response pot experiment against juveniles (J2) of the root-knot nematode Meloidogyne incognita. Successively, with different extraction procedures, a polar (melia methanol extract, MME) and a non-polar (melia oil, MO) fragments were obtained and their effects were tested on nematode motility and development, in dose and time response bioassays and pot experiments. An EC₅₀ value was calculated for all experiments. A dose–response effect was found in pot bioassays using PMF and, after an incubation period of 24 and 48 h, the EC₅₀ values were calculated at 0.41% and 0.34% w/w, respectively. Motility bioassays revealed a dose and time dependent response effect, after exposure to MME, but not to MO. Doses of MME higher than 0.08% were nematicidal, whereas lower ones were nematostatic (the loss of motility as a result of the presence of the substance was reversible). In a pot experiment, MME doses higher than 2.5% w/w caused 100% nematode control with EC₅₀ value of 0.916% w/w.