Friday, April 20, 2007

Confusion sexuelle

Sorry this post isn’t half as interesting as the title suggests! In fact it is about moths, or more precisely two particular genera of moth Cochylis and Eudemis.They might look innocent enough, but in late summer they have a regrettable fondness for laying their eggs in ripening bunches of grapes. When these eggs hatch the young larvae particularly enjoy feeding on sweet grapes. The problem isn’t the quantity of grapes that these caterpillars consume, but rather the fact that nibbled grapes are an open invitation to grey rot. If the climatic conditions are right (should that be wrong?) a damaged grape will become infected, and rot can then quickly spread to destroy the whole bunch. Untreated, in a bad year, these caterpillars can destroy a sizeable percentage of the crop. The normal solution is to spray the grapes with a chemical insecticide, but of course this blog is about the organic alternative, which is called confusion sexuelle...

I spent one morning last week spreading pheromones. In Morey this is a communal effort since a good percentage of the vineyards are protected by confusion sexuelle and indeed the method needs to be applied to a large surface area in order to be effective. At the start of each season about 500 of the diffusers pictured left are placed per hectare of vines. The small blisters are filled with synthesised female moth pheromones (one blister per species) which diffuse into the air throughout the year. The air becomes so saturated with female pheromones that come mating season the poor male moths (who navigate by smell) get all confused and unable to locate a mate. Of course no mating means no eggs, which means no caterpillars, which means no damage, which means no rot, which means good wine!

PS. Don’t feel too bad for the moths – I’m sure they just go mate in someone else’s vineyard.


Blogger eula_w said...

These posts are so interesting to read. Can't wait to read more! :D

human pheromones

5:45 AM  

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