Cucumber Beetles – Jim Jasinski, OSU Extension IPM Program
It’s that time of the year again to be thinking about cucumber beetle control on all cucurbits (melons, squash, pumpkin, cucumbers, etc.). While most seed can be purchased treated with Farmore seed treatment (fungicide and insecticide) for disease and beetle control at seeding, there are also options to apply insecticides in-furrow (imidacloprid, thiamathoxam) at seeding as well as a range of foliar spray options once the seedlings have emerged. Treatment by foliar sprays are recommended if pressure exceeds 0.5 beetles/plant on cotyledon stage plants and 2 beetles/plant for 4th leaf stage seedlings. A full list of insecticides to control cucumber beetles and other cucurbit pests can be found in the Midwest Vegetable Production Guide (http://www.btny.purdue.edu/pubs/id/id-56/90_Cucurbits.pdf).
If cucurbit plants are left unprotected, cucumber beetles can severely damage or even kill plants outright. Plants that are fed upon by cucumber beetles are also at risk for bacterial wilt infection, a disease that will become evident later in the season and has no remedy.
Only a few cucumber beetles have been seen in Columbus and South Charleston to date, but reports from southern Ohio indicate heavy pressure last week. For the next few weeks, be sure to scout newly established fields every few days for signs of beetles or damage.