Wasp trap

True, glue-traps are inhumane, but so are wasps, especially in quantities like this. In years when there is a lot of rain during the winter, the wasp population is noticeably reduced, but it seems that the snow we had in January has not had a similar effect. Local wasps prefer fish until a certain moment in September/October when all at once they suddenly prefer grapes.

That is how you know the grapes are ready to harvest.