Resistance management programs

Excellent progress has been made in the understanding of the cause, nature, genetics, mechanism and solutions of herbicide-resistant weeds since the first triazine-resistant common groundsel was reported more than 35 years ago. Resistance management programs have been extremely successful in controlling most weeds that have developed resistance to the triazine herbicides. However, research is critical to better understand the rapid increase and spread of many new weed biotypes resistant to several classes of herbicides. 

There is general agreement that as these tests are further improved with respect to their specificity and quantification accuracy, they will become essential tools in resistance management programs. 

Based on the results of field monitoring efforts, it appears certain that genes for pyrethroid resistance exist within tobacco budworm populations in this country. If effective wide area resistance management programs are not instituted immediately and sustained, the future for chemical control could be bleak for all segments of the cotton industry. 

Pyrethroid resistance management programs in the USA are still in the formative stages, but likely will evolve and mature rapidly in response to apparent increases in the relative frequencies of resistant genotypes and in the extent of their geographical distribution. The current strategy has the following elements... 

So far, pyrethroid resistance in Heliothis spp. has been documented in six countries (Table I). In Australia there has been a slow but relentless decline in the effectiveness of the pyrethroids despite the early implementation of a resistance management program. In Thailand and Turkey resistance seems to be relatively widespread and has affected cotton production in most areas. In Colombia it seems too early to tell how widespread it is. In the United States, it still seems to be confined to localized areas under... 

So far, Texas and the mid-south are the only states in the U.S. cotton belt where formal resistance management programs have been implemented. These programs are described briefly below and in more detail by D. Bull and J. Menn in this volume. In Alabama, state researchers, private consultants and industry representatives have met to discuss the implementation of a program. 

T. urticae using biological control by insecticide-resistant predatory mites is just a subsystem of this larger resistance management program. 

The success of the resistance management program for the complex of pests and natural enemies of apple in the United States, while generally good, has been mixed. In some areas of the eastern United States where OP resistance has developed in key leafroller species, increased use of nonselective pesticides such as the pyrethroids has occurred. However, in the western United States,... 

Policy is usually involved in most attempts to implement resistance management programs. In fact, policy is more often a constraint to resistance management than research limitations. 

Systematic monitoring programs that allow observation of the resistance dynamics are the basis for the development of rational resistance management concepts. The availability of detailed sensitivity profiles needs, in addition, discussion with authorities to improve resistance management programs. 

Thus, pyridalyl is expected to take an important role in IPMs and insecticide-resistance management programs and to contribute to agricultural production worldwide. 

Pyridalyl controls a wide variety of lepidopterous pest strains such as the diamondback moth (Plutella xylostella) which is resistant to various existing insecticides (8). This insecticide is also effective against thysanopterous pests. Moreover, it does not exert an adverse effect on various beneficial arthropods such as natural predator insects (e.g., Oristar-A ) and honeybees. Therefore, this novel insecticide is expected to be a usefiil material for controlling lepidopterous and thysanopterous pests in IPM and insecticide resistant management programs. 

Pyridalyl resulted from a major synthetic program based on a series of lead conq)ounds and has proven to be very active against the larvae of some inq>ortant pests of cotton and vegetable crops. Pyridalyl also controls insecticide-resistant strains of lepidopterous pests as well as susceptible strains. It produces unique insecticidal symptoms so t it may have a different mode of action from any other existing insecticides. Pyridalyl is safer to mammals and various beneficial arthropods so that it Avill provide an mq)ortant tool in IPM and insecticide resistant management programs. Pyridalyl will become a safer chemical, and certainly contribute to establishment of sustainable chemistry. 

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