Ecological Engineering in Pest Management in Horticultural and Agricultural Crops

Abstract

AbstractEcological engineering has recently emerged as a paradigm shift for considering pest management approaches that are based on cultural practices derived from ecological knowledge rather than on high technology approaches such as synthetic pesticides and genetic engineering. Ecological engineering through habitat management is an important strategy for pest suppression in integrated pest management (IPM) programme. The application of ecological engineering for pest management includes use of cultural practices usually based on vegetation management to enhance biological control or the ‘bottom-up’ effects which de-stabilizes pest build-up. Ecological engineering techniques include imparting right diversity, use of alternate food sources in the form of pollen and nectar, refugia and shelters like overwintering sites, moderate microclimate, alternate host/prey insect when primary hosts are not present, behavioural manipulation, host plant resistance and other cultural practices along with limited and selective use of pesticides. Habitat manipulation involves altering the cropping system to augment or enhance the effectiveness of a natural enemy. Different types of habitat management include trap cropping, cover cropping, intercropping, flower strips, weed strips, manipulation of field margins with flowering plants and dry mulches. Habitat manipulation approaches include top-down control (augmentative biological control) and bottom-up control. In a broader sense, two mechanisms, the ‘enemies hypothesis’ and the ‘resource concentration hypothesis’, have been identified as acting together or independently in pest population dynamics. Possible ways to enhance structural and cultural diversity include chocolate-box ecology and push-pull strategy as part of habitat manipulation. The simultaneous cultivation of several crops in the same field or judicious mixing of several plant species like field crops, pastures, trees or their combinations within the same field forms the multispecies systems. Multispecies cropping systems provide practical application of ecological principles based on biodiversity, plant interactions, conservation farming and other natural regulation mechanisms. Mixed plantings can increase the diversity of habitats and can provide alternative food sources and shelter to natural enemies. Ecological engineering for pest management is attempted in some crops such as coffee, cocoa, coconut, grapes, rice, cotton, cole crops, cucumber, carrot, apple and potato. A concerted research is necessary to develop viable technologies with consideration to conserving or increasing the efficiency of natural enemies. Removing the knowledge and extension gap between researcher and farmer is pivotal for success of the conservation and manipulation techniques in agriculture.