Effect of Some Plant Methanol Extracts on Egg Hatching and Juvenile Mortality of Root-Knot Nematode Meloidogyne incognita

This research was conducted to find out the effect of four plant methanol extracts against the root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood in laboratory at the University of Gaziosmanpasa, Turkey. For this purpose, bead tree (Melia azedarach), hops (Humulus lupulus), elderberry (Sambucus nigra), poison hemlock (Conium maculatum) were collected from different zones of the Turkey. Methanol extracts from four plant parts were screened for egg hatchability and nematicidal activity against second stage juveniles (J2) of M. incognita. The nematode eggs and juveniles were exposed to different concentrations of extracts during 24, 48 and 72 hrs. The concentrations as 0.5%, 1%, 2.5%, 5% and 10% were prepared by diluting stock solution with 10% acetone containing distilled water.
As a result, M. azedarach’s 10% (v/v) concentration significantly reduced the egg hatchability (97%) and it was followed by S. nigra (92.9%). At the end of 24 hrs incubation, 5% and 10% (v/v) concentration of M. azedarach extract and 2.5%, 5.0% and 10% (v/v) concentration of S. nigra produced 100% mortality in juvenile stage of the nematode.
The results of our investigation show that four plants contain nematicidal compounds. it seems that the use of plant extracts might have increasing popularity in future as a component or ingredient of biopesticides. Therefore, further research is necessary to found out toxic compounds released by species and carried out experiments in vivo for the control of root-knot nematode M. incognita.