How do I control cucumber beetles in dahlia?
I am a dahlia hybridizer raising about 1/2 acres of dahlia (3000 plants) with the goal of producing new show varieties. In competition insect damage in NOT acceptable in any amount. Cucumber beetles damage most of my show blooms, especially certain colors. I am in an agricultural area and I think they fly in from my neighbors. If I spray them the sprays tend to stain the blooms also. I have used Talstar, Seven and Malathion. I have been using Preference spreader sticker but now I think that is part of the staining problem. My best program is to spray the perimeter and dahlias I am not currently showing. The beetles that survive on the show varieties I hand pick or get with a vacuum.
Cucumber beetles do fly in from all over the place, and are a very common problem on susceptible crops throughout the Willamette Valley. I hope these publications are useful:
Please call me if you would like to discuss this more.
All the best,