Marigold as a trap crop: efficacy and mechanism for sustainable pest and nematode management in solanaceous vegetable crops: A review

Abstract

Vegetables are succulent herbaceous crops that are easily affected by insects, pests and diseases. This reduces the yield and productivity and, decreases the economic benefit of the crops. To mitigate this problem, farmers have increased their is not necessary use of chemical pesticides and insecticides. However, the elevated use of these chemicals for crop protection increases toxicity in the soil and plants, as most of the chemical compounds are insoluble and accumulate in the plant and soil as residues. Thus, when such pesticide-treated plants are consumed by humans and other living organisms, they affect their health, leading to the generation of several harmful diseases. In the recent days, an alternative sustainable method has been adopted to keep the population of such insect pests under the economic threshold level which is known as trap cropping. It is considered an eco-friendly method of crop protection, which is cheaper and also provides various additional benefits. One such important crop used as a trap crop in vegetable production is the marigold. It is an ornamental crop grown for aesthetic value and is highly used for the extraction of essential oil with antibacterial and anti-fungal properties. The phytoremedial and allelopathic effect of the plant checks the nematode population and also acts as a natural herbicide. It is grown as a companion crop along with solanaceous vegetables such as tomato, potato, brinjal and chilli which traps several harmful pests such as tomato fruit borer, nematodes, jassids, whiteflies, epilachna beetles, cutworm etc., and maintains their population below the threshold level which increases the marketable yield of the crop.