A Review: Using Marigolds (Tagetes spp.) as an Alternative to Chemical Nematicides for Nematode Management

Most plant parasitic nematode management methods are pre-plant treatments. One such treatment is the planting of cover crops that can reduce nematode populations. A cover crop is a crop that is grown before the main cash crop is planted. This method is used to either avoid soil erosion caused by fallowing land, or to reduce a pest that cannot reproduce on the cover crop for various reasons. Some cover crops release substances that are able to suppress other organisms. This is called allelopathy. Marigold (Tagetes spp.) which is a popular bedding plant, can be used as such a cover crop. The root exudates of marigold known to contain toxic bioactive chemicals having nematicidal, insecticidal, fungicidal, antiviral and cytotoxic activities. Thus as a method of biocontrol of plant parasitic nematodes, growing of marigolds is not only a comely but also highly economical and helps in environmental amelioration.