Due to the detrimental effect of nematicides to the environment and to human health, new alternative control methods for nematodes are more often being investigated in recent years. In this study, the nematicidial effects of Arthrobacter (ROA) and marigold (Tagetes patula) plant extracts as compared Parodine (Devguard) on three inoculum level of Meloidogyne incognita root-knot nematode (0 J2/plant, 1000J2/plant, 2000J2/plant) were investigated on greenhouse grown tomatoes and cucumber. Average plant fresh weight of control Iprodione was significantly higher than those of Tagetes patula and Arthrobacter (ROA) (P < 0.05). Statistical analysis of data taken from Tagetes patula and Arthrobacter (ROA) treatments were varied among nematode inoculum levels (P<0.05). Based on the results of this study, it suggested that because of their effectiveness, low cost and natural structure, these two substances could be good alternatives in Meloidogyne incognita control tactics, particularly, in green house crop production.