GENERAL COMMENTS

Most of the methods of application described in the preceding chapters illustrate the present state of the art in terms of adoption by farmers in different parts of the world. The latest technology aimed at optimising dosage transfer with minimal environmental pollution is not always used by growers who continue to use old equipment or are unaware of alternative methods. Everywhere people are increasing their opposition to the use of pesticides, yet they still require good-quality produce at low cost. Scientists, in response to the initial criticism of pesticides by Carson (1962), have developed the concept of integrated pest management with greater emphasis on natural controls, namely cultural and biological. As indicated in the Preface, much attention is now being given to development of genetically engineered crops with increased resistance to pests — development which is also attracting vocal opposition from the public as they perceive adverse effects from long-term exposure to small amounts of toxic chemicals in food crops. Genetically engineered crops so far have resistance usually only to one type of pest and other pests can still affect yields and crop quality. Crop cultivars, whether naturally selected or genetically engineered, that are resistant to pests often contain higher quantities of some substances which are toxic, thus, some lettuces resistant to aphids have a bitter taste and some varieties of potatoes were withdrawn due to unacceptable levels of solanin…