The effect of certaىn plant extracts on the development of the root-knot nematode Meloidogyn incognita was studied under laboratory and greenhouse conditions. Root extracts of acetone and petroleum ether of american coneflower Echinacea angustifolia stimulated the egg hatching of M. incognita at 200 and 400 p.p.m. The highest rate of nematode reduction was obtained with high concentration of fenugreek Trigoneilafenumgraecum and neem Azadirchata indica (acetone solvent extract), where the percentage reductions were 75.48 and 66.73%; respectively . The highest reduction in eggmasses, nematode final population and gall formation was obtained with the dry powder of neem followed by those of melia Melia azadrach, american coneflower and fenugreek in adescending order. The plant growth of sunflower Helianthus anuus was positively correlated with the increase of added powders of all tested plants. Application of the moderate and high rate of fenugreek improved the plant growth of sunflower plants.