Pea moth pheromone

Perry, J. N., and Wall, C. (1984). Orientation of male pea moth, Cydia nigricana, to pheromone traps in a wheat crop. EntomologiaExperimentalis etApplicata 37,161-167. 

The trans acetate 25 is the pheromone used to trap pea moths.6 Changing the -alkene into the acetylene allows the disconnection next to what was the double bond. The only problem is how to make a mono-bromide from the symmetrical diol 30. 

The next example is the pheromone of the pea-moth, and can be used to trap the insects (see the introduction to Chapter 24). After disconnecting the ester, FGI on the trans double bond gives an alkyne. 

The trans acetate (16) is the pheromone used to trap pea moths to tell the farmer exactly when to spray to eliminate these destructive pests. It can be made from trans alcohol (17) and hence from acetylene (18) by reduction. Disconnection of (18) eventually requires an unsymmetrical compound (19). Diol (20) is available in large quantities so the statistical method (Chapter 5) can be used as very high yields are not so important when the starting material is cheap and the TM required in only small amounts-... 

But, on a slightly larger scale, shape is not usually so well defined. Rotation is possible about single bonds and this rotation means that, while the localized arrangement of atoms stays the same (every saturated carbon atom is still always tetrahedral), the molecule as a whole can adopt a number of different shapes. Shown on the next page are several snapshot views of one molecule—it happens to be a pheromone used by pea moths to attract a mate. Although the structures look dissimilar, they differ from one another only hy rotation about one or more single bonds. Whilst the overall shapes differ, the localized structure is stiU the... 

Economic thresholds have been calculated for many pests and are an important tool in IPM. An eeonomie threshold is the population of pests which if controlled will give a yield return that will pay for the cost of pesticide and application. Where available these have been ineluded in Table 7.1. Another important tool to help with deeision making for appheation of a pesticide is the use of forecasts of pest populations. A number of oiganisations run forecasting services for some important crop pests sueh as eutworm, pea moth and carrot fly. These forecasts combined with erop monitoring and use of traps including pheromone traps can all help to reduee the requirement for pestieide applications. 

One or more sprays of a synthetic pyrethroid insecticide. The timing is important. PGRO run a pea moth monitoring service. Growers can use pheromone traps to aid spray decisions. 

This pheromone trap removes the males of the pea moth Cydia nigricana from circulation. 

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