Effects of some plant extracts on root-knot nematodes in vitro and in vivo conditions

One of the major pests of the vegetables, root knot nematodes (Meloidogyne spp.) (Tylenchina: Meloidogynidae) (RKNs) can cause economic losses by forming knots on the host plant roots. RKNs are more prevalent in the greenhouse vegetable growing areas of the coastal regions. In this study, the effects of plant extracts from five different plants; Capsicum frutescens, Hyoscyamus niger (Solanaceae), Melia azedarach (Meliaceae), Xanthium strumarium and Achillea wilhelmsii (Asteraceae) were evaluated against RKNs. In the first studies; the effects of plant extracts (0.5, 1.0, 1.5, 3.0, 6.0 and 12.0% concentrations) on eggs, egg masses and second stage juveniles (J2s) of the Meloidogyne incognita were evaluated in laboratory conditions (in vitro tests). Concentrations of 3.0, 6.0 and 12.0% for H. niger, X. strumarium and M. azedarach caused 100% inhibition of egg hatching and J2s mortality. Effects of the same plant extracts against M. javanica on egg mass of nematode (I), the plant height (II), the plant age (III) plant dry weight (IV), root fresh weight (V) and root dry weight (VI) were also evaluated in greenhouse-pot studies. Result of pot trials, 12.0% of H. niger and X strumarium has shown high effect on hatching studies. In the toxicity studies, 6.0% and 12.0% of X. strumarium and M. azedarach were found effective.Three plant extracts (X. strumarium, H. niger and M. azedarach), against mixed populations of M. incognita and M. javanica on tomatoes under natural greenhouse conditions (in vivo) were evaluated. Treatmets were repeated 4 times by watering for each pot (extract were applied 1 ml plant(-1)). In greenhouse trials, root gal indicies (root knot) and crop yield (tomatoes) (kg plant(-1)) values and effect of root gal indicies and yield (%) were evaluated. In vivo studies, it could be concluded that, only the M. azedarach has effected the galling indicies and consequentelly crop yield significantly.