Other Insect Control Strategies

Several compounds are used as insecticides where little is known about their biochemical mode of action or whether they are general toxicants. Some have been around for many years, some are of natural origin and others are living organisms that predate on insects. 

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The analysis of neuropeptides in insects may lead to the development of both specific insect control strategies and model systems that clarify the role of neuropeptides in all animals. Therefore it is important to vigorously pursue neuropeptide studies and to exploit the available technologies to the fullest. This paper will review the importance of current recombinant DNA techniques to the study of neuropeptide biology. Studies of the adipokinetic hormone (AKH) family will be emphasized as examples, but other peptides will be mentioned to present a broader picture of the advantages and problems associated with the techniques. 

Since Insects lack the capacity to biosynthesize the steroid nucleus, they generally require a dietary source of sterol for normal development and reproduction U). This is an important area of biochemical difference, between insects and many other organisms, that might be exploited to develop new pest control strategies. Cholesterol will satisfy this dietary requirement in all but two known cases in which dietary A -sterols are essential (2,2). In addition, some insects may obtain an adequate supply of sterol from symbionts or intestinal microorganisms. 

A different strategy for controlled release is based on polymer permeability other than degradation. The active reagent may be encapsulated within a polymeric membrane or in a strip, as shown in Figure 5.53. Ideally the reagent is contained in the reservoir as a saturated solution with excess in suspension. This allows diffusion through the membrane at constant rate without loss of activity. Alternatively, the reagent may be dispersed in a polymer matrix and released to the environment by diffusion or extraction. A variety of membrane and matrix devices are commercially available [99]. Pheromone release strips for insect control and household fly and cockroach strips for release of insecticide are also in commercial use. 

Control of insect pests and invasive weeds has become very sophisticated. Knowledge of the interaction between insects and host plants is critical to development of effective control strategies diat are friendly to the environment. We must also understand how insects communicate with each other. What are the semiochemicals (signal substances such as sex pheromones) and how do they function Research efforts in this fast-growing field involve organic chemists, analytical chemists, entomologists, biochemists, microbiologists, formulation experts, and statisticians. 

Others also have proposed that allelochemicals could prove useful in crcp protection, especially for minimizing the agricultural losses due to insects and nematodes, and for controlling diseases. The USDA Research Planning Conference in 1977 estimated that technological advances could reduce substantially the 30 billion in annual losses caused by pests and the cost of their control (37). This conference proposed the following strategies for research Tn allelopathy. 

IRAC was formed in 1984 to provide a coordinated crop protection industry response to prevent or delay the development of resistance in insect and mite pests. The mission of IRAC is to promote the development of resistance management strategies in crop protection, vector control and in other areas of insecticide use so as to maintain efficacy and support sustainable agriculture and improved pub-... 

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