Vegetable Crop Insect Scouting

David Owens, Extension Entomologist,

With warm weather in the forecast for this weekend, be sure to scout for striped cucumber beetle. Last year, I found my first striped cucumber beetle on May 14. In 2018 a couple of weeks of cool, wet May weather ‘broke’ during a weekend and beetles were numerous early the following week. Scouting for the early season influx is going to be especially important this year as transplants are much smaller than they were at this point last year. Once overwintering pioneer males find cucurbits and begin feeding, they release an aggregation pheromone that calls in males and females, resulting in large numbers quickly.

Continue scouting for spider mites, especially in greenhouses. If planting infested melons, keep a close eye on the interior of the field, not just field edges. Based upon the last couple of seasons’ observations, a clean field will be infested from weedy margins and from woodline edges, especially those with pokeweed. Mites tend to appear in these areas between the 2nd and 4th week of June.

Be sure to scout for Colorado potato beetles this week. These beetles cannot fly below 80 °F, with the warm weather yesterday, today, and tomorrow, they may begin to appear in fields. Recent work by Tom Kuhar and Helene Doughty in Painter shows that residual efficacy starts to decline somewhere between 30 and 40 days after planting.

The UD insect trapping network has been deployed. Trap counts will be uploaded here: by Tuesday and Friday mornings. When sweet corn is closer to silking, Thursday moth counts will be included in the Weekly Crop Update.