Marigold, an annual warm-season plant with a bushy growth habit, is characterized by its vibrant orange, red, and yellow flowers. Beyond its aesthetic appeal, marigolds play a valuable role in agriculture by attracting beneficial insects like ladybirds, hoverflies, and parasitic wasps, which help maintain ecological balance and pest control.
What sets marigold apart is its significance in nematology due to its ability to produce allelopathic compounds, particularly terthienyl, that are known to be detrimental to several species of plant-parasitic nematodes. Notably, Pratylenchus (lesion nematodes) and Meloidogyne (root-knot nematodes) are consistently affected by marigold. Marigolds contribute to reducing plant-parasitic nematode (PPN) populations through multiple mechanisms, including acting as a non-host or a poor host, producing allelopathic compounds that are toxic to or inhibit PPN development, creating an environment conducive to nematode antagonistic flora or fauna, and even behaving as a trap crop, making them a valuable asset in sustainable agriculture practices.