Ecological Management of Agricultural Pests Through Allelopathy

Allelopathy is a naturally occurring ecological phenomenon in which the living organisms produce and release the biochemicals (allelochemicals) in the environment that affect the growth, development, reproduction, and survival of other living organisms in the surrounding environment. For field crops, the phenomenon of allelopathy can be exploited in the form of intercropping, use of cover crops, mulching, crop rotations, and use of plant water extracts alone or in combination with reduced doses of herbicides to provide effective control of the agricultural pests and diseases. For the control of insect pests (field and storage insect pests), the use of allelopathic plant water extracts and the powder of allelopathic plants may be quite useful. The allelochemicals affect the growth of unwanted plants (e.g., weeds) through changes in the cell structure, inhibition of cell elongation/division, disruption of membrane structures, and disruption of water and nutrient uptake and the process of photosynthesis. The phenomenon of allelopathy is ecofriendly, and it may help significantly reduce the usage of pesticides. Thus, the phenomenon of allelopathy provides an attractive ecological alternative to pesticides for controlling the pests and diseases of the agricultural crops. In this chapter, we have discussed the mechanism of allelochemicals for growth inhibition in plants and the role of crop rotation, allelopathic mulches, allelopathic cover crops, intercrops, and allelopathic water extracts (alone or with reduced doses of herbicides) in weed management. The role of allopathic water extracts and allelopathic powders for managing the insect pests and diseases has also been described.