Watch for Cucumber Beetles in Fall Pumpkins, Squash

Although striped cucumber beetle (see photo, left) and squash bug (below, left) infestations have been very low throughout the summer, we are beginning to see an increase in insect counts this week. This time of year, it is common to see either or both pests aggregating on pumpkin or squash fruit, often feeding near the top of the fruit. Beetles are likely moving to cucurbit fruit as vine/leaf tissues begin to die down (watch for first frost). Although fruit damage may currently be low, growers should continue to monitor fruit quality between now and harvest. Plant samples taken at Rosemount this past week (Sept. 10th) indicated approx. 3/60 pumpkins (5%) with some feeding damage. However, one reason for concern is that beetle counts increased dramatically in the past 3 days. Counts increased to 35-120/trap between Sept. 10-13, at Rosemount (Dakota Co.). Feeding damage is usually aggregated in fields (due to beetle feeding/aggregation behavior), and “spot” treatments, vs. whole-field sprays, can often alleviate the problem. Because treatment may be needed, and may occur near harvest, growers should be very careful to note the pre-harvest interval (minimum number of days before harvest) for a given insecticide. A few selected options, with pre-harvest intervals, are shown below.