Development costs, pesticides

The cost of discovering and developing a new pesticide runs into millions of dollars (2-3). Part of this cost can be attributed to research necessary for producing satisfactory formulations. As formulations become more sophisticated the development costs become increasingly higher. In order to help reduce formulation development costs, we need to continually evaluate promising new tools for their cost-saving potentials. 

This table illustrates one of the major impediments to the rapid assimilation of immunochemical technology into pesticide residue analysis labs. Because of the amount and variety of work involved, new method development costs may be high when compared to routine chromatographic methods. However, the low cost per run allows for rapid recovery of the initial investment with sufficiently high sample loads. For example, the cost of reagents and supplies for an ELISA for diflubenzuron was estimated to be 0.20/sample as compared with 4 for HPLC or 11 for GC (35). In addition to the lower reagent and supply costs, the major economic advantage of immunoassay is the dramatic decrease in labor costs. 

There is also much room for improvement in application and formulation technique for chemical pesticides to reduce the environmental pollution, since the major portion of an applied pesticide often hits nontarget organisms rather than target pests. Any improvement in methodology to simplify the chronic toxicity tests that can cut down the immense costs and amount of scientific manpower involved will certainly encourage the development of pesticide chemistry. 

Before moving on to look in detail at the discovery and development of new pesticides it is worthwhile briefly reviewing public concern over the safety of chemicals in, and their effect on, the environment. As we shall see, public attitudes have had a major effect on both the time scale and cost of developing new pesticides. 

The great importance of research directed towards developing new pesticides has already been emphasized. The purpose of the present section is to discuss the way in which this work is carried out and the factors which have influenced and are still influencing the cost, the time-scale and the nature of the testing programme. Effects of public opinion, introduced in the previous section, will be much in evidence. 

Historically, the discovery of one effective herbicide has led quickly to the preparation and screening of a family of imitative chemicals (3). Herbicide developers have traditionally used combinations of experience, art-based approaches, and intuitive appHcations of classical stmcture—activity relationships to imitate, increase, or make more selective the activity of the parent compound. This trial-and-error process depends on the costs and availabiUties of appropriate starting materials, ease of synthesis of usually inactive intermediates, and alterations of parent compound chemical properties by stepwise addition of substituents that have been effective in the development of other pesticides, eg, halogens or substituted amino groups. The reason a particular imitative compound works is seldom understood, and other pesticidal appHcations are not readily predictable. Novices in this traditional, quite random, process requite several years of training and experience in order to function productively. 

Since the mid 1940s, pest populations have been developing resistance to synthetic pesticides. To overcome this resistance, additional pesticide treatments and more costly controls have been required to achieve desired levels of pest control. This costs farmers about 1 billion each year (Pimentel, D., in manuscript). 

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