Mating disruption method

Mating disruption method This pest management technique interferes directly with the communication system between the male and female, and has demonstrated successes for more than 25 years. By means of exposure to an extensive cloud of pheromone, the male insects are confused. They can no longer locate their mate, which reduces the population of the next... 

Pests and their pheromones relevant to agriculture and forestry. ( used via mating disruption method). 

Different from the use of ordinal insecticides, this disruption method has high target selectivity and, as would be desired, ensures the survival of natural enemies. The sex pheromone, which shows no toxicity to mammals, is an ideal insect-behavior regulator (IBR). Table 8 shows the application areas of main mating disruptants for lepidopteran insects. In addition to the use of the synthetic pheromone of P. gossypiella in large cotton fields, many disruptants are... 

Male attraction to the female sex pheromone has been studied for the development of environmentally safe control methods. One important drawback of the mating disruption technique is that only male behaviour is affected, so the efficacy of pheromonal methods can be greatly enhanced by compounds that affect also female behaviour [378]. 

The fact that mating disruption can be commercially feasible is encouraging but the actual mechanism(s) of disruption is still unclear. The possible mechanisms involved in disruption include sensory adaptation, habituation, competition ("false-trail following") and camouflage of aerial trails from females (14, 15). These mechansims could be working in combination, simultaneously or sequentially, so that some level of disruption can and does occur under a variety of conditions. Without a better understanding of the mechanisms of "attraction" to a pheromone source and the mating disruption process, however, optimization of control methods can proceed only on an empirical basis. 

The behavior of two other formulations, microcapsules and small plastic laminate flakes, containing tetradecenol formate, were compared in applictions to plots of mature corn at Beltsville, in August 1980. (8) The Z-9-tetradecen-1-ol formate (TDF) is a mating disruptant, rather than a true pheromone, of the Heliothis species of moths. It was selected in these experiments because reliable analytical methods were available (9) and its behavior was expected to be similar to that of the actual pheromones, whose chemical structures and properties are also similar. The two formulations were polyurea-polyamide microcapsules 5-microns in diameter supplied by ICI at Bracknell, Berkshire, England, and a small (3 mm side) plastic laminate formulation supplied by the Herculite Corporation of York, PA. The microcapsules were applied at 300 g of TDF per hectare and the flakes at 285 g/h. Both formulations were applied by air to mature corn 240-270 cm in height in clear, hot weather with a daily maximum temperature of 39°C. 

Nowadays, there are three appUcation methods used for pest control in agriculture and forestry monitoring, mass trapping and mating disruption. 

Another example of organic synthesis via cross-metathesis is the synthesis of biologically active compounds such as insect pheromones. Use of such pheromones offers an effective and selective pest control method. Thus, cross-metathesis of ethyl oleate with 5-decene results in a cis-trans mixture of ethyl 9-tetradecenoate, an insect pheromone precursor [15]. Cross-metathesis of methyl d.y-5-eicosenoate (obtained from meadowfoam oil) with excess 5-decene gives methyl tm 5-decenoate, which can be transformed into a 83 17 mixture of trani -5-decenylacetate and tran.y-5-decenol (in total 90% trans), the sex pheromone of the Peach Twig Borer moth, a major pest in Northern Hemisphere fruit orchards. The isomeric mixture was active in mating disruption [16]. Other examples of organic synthesis via cross-metathesis are summarised elsewhere [17 18]. 

Figure 1 The classic yeast two-hybrid method and derivatives, (a) Schematic diagram of the yeast two-hybrid approach, describing an interaction between protein X and protein Y. Protein X is fused to a transcription factor DNA-binding domain (the "bait" construct), and protein Y is fused to a transcription factor activation domain (the "prey" construct), (b) High-throughput applications of the yeast two-hybrid method use mating of haploid strains carrying bait and prey, respectively. Hybrids can be mated in arrayed formats (as shown) or as libraries, (c) The reverse two-hybrid method uses a counter-selectable marker to indicate loss of protein interaction because of disruption by an inhibitor protein/small molecule ("/" illustrated in the diagram) or mutation(s) in proteins X and/or Y.

The method described above is the easiest, but not necessarily the best way to graft tissues. With practice, one can make grafts between free, unconstrained embryos lying in a dish. This is the least disruptive and yields the best results, if done correctly. It is important that the edges of grafts are mated precisely. The grafts should be relatively small, and they must stick in the graft site without external pressure, all of which require much practice. 

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