The push-pull strategy: A new approach to the eco-friendly method of pest management in agriculture
Push pull strategy of integrated pest management in agriculture involves the behavioral manipulations of insect pests and their natural enemies by the use of behavior modifying stimuli which makes the main crop comparatively unattractive and unpalatable to the pests while diverting them to the more attractive sources from where they are removed. Continuous injudicious application of long persistent broad spectrum pesticides for pest control, essentially debilitate the beneficial natural enemies, essential pollinators and foragers, thereby enter into vertebrate food chain resulting into bio-magnification. These result into secondary pest outbreak and development of pesticide resistance in insect pests and emergence of pest biotypes. Push pull strategy of integrated pest management is a newly emerged pest control method which uses non-toxic components for pest population reduction with reduced pesticide input. The Push pull effect is established by the use of exploiting semiochemicals which deter the pests from the main crop (“push”) and attract them into trap crops (“pull”). Intercropping or companion cropping is done for semiochemicals delivery which mask host stimuli and act as a repellent and deterrent. However, the Push-pull method has a number of advantages in agriculture. Companion crops and intercrops usually serve as a good fodder for the farm animals, while leguminous intercrops add adequate organic matter and nitrogen to the soil by nitrogen fixation. A good number of trap crops help with the water retention and bind the soil particles, thus prevent soil erosion and nutrient leaching. The major benefit is that certain intercrops and trap crops used in this strategy may also help in the control of weeds by dramatic reduction of the weed seed bank in the soil due to allelopathic effect. Thus Push pull strategy could be a useful method in Integrated pest management programme to increase agricultural productivity.