Four Marigold Species as Control Agents of Root Knot Nematodes

The Root knot nematodes (Meloidogyne spp.) are major limiting factors in growing many agricultural crops. With the aim of producing a healthy crop, cultivation of some plants with allelopathic effects on nematodes is one of the most effective control measure against root knot nematodes. This method can be used as an excellent substitute of chemical treatment. Marigolds (Tagetes spp.) are herbaceous plants of family Astraceae with more than 50 species, can be used as ornamental cover crops. Nematicidal effects of marigolds on several nematodes had been proved. Marigolds produce alpha-terthienyl enzyme, which can control root-knot nematodes and other pests and pathogens such as fungi, bacteria and insects. It also has positive role in promoting growth of bedding plants. In this article, important marigold species including Tagetes tenuiifolia Cav., T. minuta L., T. patula L. and T. erecta L., have been introduced.