Abby Seaman, Marcus Lopez, Bryan Brown
Squash bug can be especially tricky to work with in a research setting because there’s no guarantee that they’ll make an appearance in your plots, and also because they lay their eggs in masses of 10-30, so their distribution can be clumpy and difficult to quantify.
Well, they definitely made an appearance in this trial. We started finding adults and egg masses as soon as we started scouting the week of July 1st, and we continue to find adults and new egg masses as late as last week. The recommended threshold for squash bug in conventional production is one egg mass per plant. We decided to use a threshold of 0.5 egg masses per plant because we know the insecticide we planned to use, a product that’s pre-mix of pyrethrins and azadirachtin (from the neem plant), kills at best 60-70% of the bugs. Only the plastic mulch treatment was over threshold the week of July 7 but because of equipment constraints we had to spray all treatments. Because most insecticides are not effective against insect eggs, we wanted to wait until most of the egg masses had hatched. Our first application went on July 31st, with the goal of finding a sweet spot between letting as many eggs hatch as possible, and not letting the early hatched nymphs get too big. Larger immature insects are harder to control than smaller ones. Because those adults are still out there laying eggs, we’re over threshold for egg masses again the week of August 2nd, and will be waiting again for more eggs to hatch before another application.
Adult squash bug
Squash bug egg masses
Newly hatched squash bug nymphs