adjusting the time of crop harvesting helps prevent pest infestation.Explain in your own words.
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Answer:
Cultural controls are the oldest methods that have been used to manage pest populations. However, with the development of synthetic pesticides these controls were rapidly abandoned or de-emphasized and research on them was largely discontinued. Because cultural controls are preventative rather than curative they are dependent on long-range planning. Also, because they are dependent on detailed knowledge of the bio-ecology of the crop-pests-natural controls-environment relationships, most of which, in the past, were poorly understood, the results were very variable, and it was often difficult to evaluate their effectiveness. It is understandable that most farmers were eventually won over to the, at first, more reliable and less knowledge- and skill- dependent toxic chemical solutions to pest problems.
Today the situation is very differnt from those early days of pest control. We have a much better understanding of the bio-ecological relationships within crop systems; predictive computer models are available for some pests; and the social climate is demanding reduced dependence on toxic chemicals to solve problems. Such concerns have developed as a result of numerous pesticide accidents, detection of residues in recreational environments, drinking water, foods and human tissues, the increase in the incidence of pesticide-related allergy and petrochemical sensitivity, the growing interest in the relationships between food quality and human health (and the associated expanding organic food market), the decreasing effectiveness of many pesticides as more and more pests become resistant to them, and their increasing costs.
Pest control scientists have responded to this situation by promoting a philosophy of pest management and integrated pest control (IPM). At first these approaches, encouraged by the chemical companies, emphasized the efficient use of pesticides, claiming that problems associated with these poisons could usually be traced to their misuse. However, there is ample evidence that problems often arise even when pesticides are used as recommended. This is not surprising as pesticides are largely non-selective and are as lethal to the 99.9% of insect species that are beneficial or neutral with respect to humans, as to the 0.1% that are pests; and most correctly applied pesticide still misses its target. Because of these and other problems associated with pesticides it seems reasonable to expect that we will eventually have to restrict their use to socially important emergencies (for example, in the future, control of a tobacco pest may not be regarded as a socially important emergency.)