The effect of plant extracts of eucalyptus (Eucalyptus chamadulonsis) , garlic (Allium sativium), marigold (Tagetes erecta) and neem (Azadirachta indica) and essential oils were tested against the root-knot nematode, Meloidogyne incognita. All tested treatments had nematicidal effect on nematode juveniles in vitro after 24 and 48 hours from exposures. The highest percentage of nematode mortality was achieved by application of neem (65.4%), essential oils (64.4%) and marigold (60.5%), followed by garlic and eucalyptus (38.7- 39.5 %). Under greenhouse and field conditions, neem extract and essential oils treatments were more effective in reducing population numbers of the M. incognita in soil and root gall index compared to other treatments. Also, in field experiments the highest reduction of root gall index was achieved by neem treatment and essential oils, 44.2 and 32.6% respectively.