Cucumber Beetles

Asked August 4, 2020, 5:59 PM EDT

Hello Extension Experts! We are having a cucumber beetle problem on our flower farm on Sauvie Island. The most concerning damage is on our dahlias. They are eating up the flowers and we are concerned now about the tubers. We are neeming regularly, covering flowers in mesh bag and vacuuming them up whenever we see them but they are getting worse. Are the tubers at risk? Any advice would be appreciated! Thank you, Jen Rich

Multnomah County Oregon

1 Response

Cucumber beetle larvae do feed on roots, however they feed on multiple kinds of host plants and are typically most injurious when these plants are young. It's hard to say if they are feeding on the tubers, and it is likely that the tubers would not sustain a lot of damage due to their bulk and size. Have you tried digging in the soil to check a tuber? It sounds like you are already doing a number of management tactics, however there is some information below that might give you some additional ideas:

This article below, although primarily about curcurbits, has some good information about biology and management of the insects:

Here is info specific to dahlia:

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