You may be seeing a few “stink bug-like” insects crawling around on your cucurbit crops this time of year. However, these slightly more slender insects are not stink bugs, they are actually squash bugs. Similarly to stink bugs though, they do give off quite an odor when crushed!
Squash bug adults and nymphs (immatures) (Figures 1 – 3) attack all cucurbit vine crops, especially squash, pumpkin, cucumber, and melon. These insects feed by sticking their needle-like mouthparts into plant parts to sip on sap. Feeding damage by adults and nymphs can cause significant damage to the fruit and foliage: damaged fruits are disfigured and discolored, and leaves may wilt and become brittle and discolored as well.
Figure 1. Adult squash bug laying eggs. Photo by John Obermeyer.
Figure 2. Squash bug nymphs and eggs. Photo by John Obermeyer.
Figure 3. Squash bug nymph on pumpkin. Photo by Liz Maynard.
Generally, squash bugs are not a problem if controlled earlier in the season with insecticides. If not however, it’s still possible to see adults, nymphs, and even egg masses on plants as we move into the fall. Feeding by nymphs and adults can still cause serious damage and reduce the marketability of pumpkins. So if you have doubts, continue to scout your pumpkins for all life stages through September. If insecticides are necessary, options include organic products with an active ingredient like Azadirachtin + pyrethrins (for example Azera®), and conventional products with active ingredients Carbaryl (for example Sevin XLR Plus®), Permethrin (for example Ambush®), Bifenthrin (for example Brigade®), and Esfenvalerate (for example Asana XL®). Insecticides should be focused on nymphs, as they are the most susceptible life stage. Please be sure to consult pesticide labels for pre-harvest intervals.
If you find that you don’t need to squash those bugs, great! But a task still remains for you: now is the time to focus on removing any excess cucurbit fruits, foliage, or any other plant debris from your fields. This is important because it will eliminate food sources and sheltered places in the field where adults can survive the winter. While nymphs are killed by freezing temperatures, adult squash bugs can survive the winter in protected sites (like plant debris!). Here’s to hoping squash bugs won’t get in the way of a happy harvest!