Effect of some plant extracts on larval mortality against the stem nematode (Ditylenchusdipsaci) and compared with synthetic pesticides.

Studies were carried out in 2014,in department of plant protection-Damascus University, to determine the nematicidal effect of leaves of Inulaviscosa, dry fruits of Meliaazedaracht, whole plant of Tagetespatula and leaves of Eucalyptus camaldulensis on the stem nematode (DitylenchusdipsaciKuhn, 1857)and compared with synthetic pesticides (carbofuran, methomyl, carbaryl and dimethoate) in vitro.The ethanol extracts of the tested plants were the most toxic against D. dipsaci, followed by water extracts. Ethanol extracts of Inulaviscosahad the highest effect on fourth-stage juveniles (J4)the corrected mortality %, (78%&82%), followed by ethanol extract of Meliaazedarachtwhich gave the corrected mortality %, (73%& 77%) after 24 and 48 hrs. of exposer, respectively.The concentration of 100 mg/kg -1 of carbofuran, methomyl, carbaryl and dimethoate gave the corrected mortality %,:94%, 89%, 43% and 65 % of the treated juveniles (J4) nematodes after 48 hrs. Carbofuran and methomyl had better activity as compared to water and methanol extracts of tested plants. When the dead nematodes were studied under the microscope it became apparent that they had either one of four very distinct shapes, namely: straight (I-shape), bent (banana- shape), sigmoid (∑-shape), or curly (∞-shape). We can arranged the effect of plant extraction and pesticides at corrected mortality %: carbofuran>methomyl> Inulaviscosa> Meliaazedarach> dimethoate>Tagetespatula>carbaryl>Eucalyptus camaldulensis.In the consequence, Ethanol and water extracts of leaves of Inulaviscosa and dry fruits of Meliaazedarachtshowed