Spotted -wing Drosophila
I was wondering if there are any things that I can do early in the season to help my raspberry crop from being ruined this year by the Spotted-wing Drosophila
Burleigh County North Dakota
First of all, don't panic. This is a new pest. It probably will not be in your patch this year.
The key to managing the spotted wing drosophila (SWD) is to monitor for it. Set out baits once the fruits begin to form. A common bait mix is 4T of sugar and 1T of dry yeast stirred in a cup of 12 ounces of water. A yellow sticky board may be inserted into the cup to visually attract the flies.
The flies are tiny (1/10 inch long. Use a hand lens. A fruit fly has a red eye. The SWD males have a large spot on each of their wings. You can go online for more photos and information.
If you find the SWD in your patch, you may consider spraying with insecticides to protect the fruit. Malathion will be the predominant insecticide since it is effective, yet has a short life. You can pick the fruits one day after spraying. Harvest the fruits regularly. Organic options such as spinosad and pyrethrins are available, too.
Let me know if you have more questions.