Cleaning Our Grape Clusters

In addition to Counting Clusters we have been going through the vineyard to get rid of raisiny looking grapes.

The question is, what causes grapes to look like that. My husband thought that we might have a problem with the spotted wing drosophila so I am looking into this. I recall that there was a post that described a method of trapping the drosophila and I found it here: Spotted Wing Drosophila.

The method is simple: Create a trap from a clear plastic cup with a lid. Make small holes in the plastic lid. Make two holes on the sides of the cup near the top and insert wire, string or twist ties in the holes to enable it to be hung. Get yellow sticky cards to put on the inside of the plastic cup and fill the bottom with apple cider vinegar. Hang the trap near a grapevine. The vinegar acts as an attractant and the yellow sticky card will trap the insects.

The female and male spotted wing drosophila look like the following photo. It is the male that has the spots on it's wings, the female does not have any spots.

The female, however, is the destructrix. Using her saw-like ovipositor she deposits her eggs inside sound fruit providing a home for the developing larvae.
Click here: Drosophila suzukii for a closeup view of the male and female spotted wing drosophila as well as distinguishing characteristics between a spotted wing drosophila female and a female drosophila ovipositor.


References:
1. Washington State University IPM: Spotted Wing Drosophila.
2. Ministry of Agriculture, British Columbia, Spotted Wing Drosophila (Fruit Fly) Pest Alert.