Thursday, August 27, 2015

Programs utilizing pheromones

Pest control strategies tend to follow either a preventive (eradicative) approach or a containment (corrective) approach (Smith 1972). A treatment is used in a preventive manner if used prophylactically or by calendar dates, and in a contain- ment manner if used only when pest densities are above a certain threshold. All the arguments for and against eradication cannot be enumerated here. The concept has strong proponents (Knipling 1972) who argue that a concerted attack on the total population of an insect is one of the best ways to tackle some of the major species. It may be attractive to think of the many new techniques as an arsenal to be deployed against the insect enemy with destruction the aim. The realization by a large body of entomologists, however, that disruptive approaches to pest control can intensify rather than solve a problem, or induce new problems, has led to the approach of managing a pest population using a variety of methods. In this integrat- ed control methodno attempt is made to eradicate a pest, but rather to maintain its population below an economic threshold level. Learn more about pheromones at

Programs utilizing pheromones

Several different approaches are described in this chapter. The boll weevil pro- gram, for example, is an attempt to eradicate the insect from a large area using a variety of techniques. Pheromones work according to Other pilot studies are attempting to demonstrate whether or not pheromones are capable of manipulating pest populations to effect satisfactory control. 

2.1.2. Evaluating the effectiveness of pheromone tests

As with any treatment to suppress an insect pest population, it is not enough to count the number of insects trapped as indicative of the efficacy of the method. Some independent estimate is necessary of the percentage mortality caused by the treatment on the population. Ideally, life table information should also be available to evaluate what percentage mortality will have a significant effect on subsequent population levels.

Research on population dynamics of pest insects hand-in-hand with control methods is one of the most needed areas of applied research. This type of research is time consuming and expensive and as a consequence is often neglected. In exam- ining the various case histories it may be illuminating to ask how much is known about the populations they are working with. Economic thresholds need to be established to determine whether it is really necessary to reduce the pest population to a minimal level, and economic thresholds have still not been adequately deter- mined for a majority of pest species. To compound the problem, current marketing regulations set injury levels for many crops at a level that can hardly be justified on any rational basis.  Why Expect human to have pheromones.

In all pheromone field tests there is a severe problem in providing a check situation against which to assess the effects of the treatment. One method is to measure the trend of the population over time and to evaluate how much the imposed treatment deflects the population level from this trend. A second way is use of an untreated plot. However, if this is close enough to the treatment plot to be part of the same population, the effects of pheromone on the population of the check plot could be very real. If a remote population is chosen to avoid this effect, there is no basis for assuming that the population trend will be in the same direc- tion as that in the treatment area: its use as a control may very well give specious information. Thirdly, checks can be, and frequently are, omitted altogether saving expense and ensuring treatment ‘success’ whatever the result.

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