I personally go to about 15 farms each week. The insects we look for are ones that you are probably familiar with-mainly spotted winged drosophila, but also brown marmorated stink bug, lygus bugs, aphids, and beneficial insects like bees, lacewings, lady beetles, and minute piratebugs. I have definitely found the insect searching and counting to be the most straightforward-there aren’t many insects I can’t ID with a sample and google. But I also look for symptoms of fungal, viral, and bacterial infections in the plant, which can be much more difficult. There are lots of symptoms that can be caused by a range of things, making it much less clear-cut than IDing an insect. For instance, leaf yellowing could be nutrient related, a viral infection, chemical damage, root rot, etc. I am starting to get the hang of it, but there is a lot of second-guessing involved.
As I mentioned, spotted winged drosophila is the insect we care the most about, and I do a TON of trapping and counting them. SWD is a fruit fly that is relatively new to berry farmers in the US. It arrived from Asia in 2008 and has since exploded in California and the Pacific Northwest. As of a couple years ago, it was established in MN as well. The female has a strong serrated ovipositor that makes her able to saw into soft fruit to lay eggs, and their fast generation time makes it so that any berries that ripen later in the season can be pretty heavily impacted. We trap them with apple cider vinegar mixed with white wine-they can’t resist it! The trapping isn’t intended to reduce the population though-it is only an indicator of the population
Unfortunately, there isn’t a great solution to combat these guys either, particularly for organic farmers. The best way is just to try to keep ripe fruit out of the field, harvest as early as possible, and plant early-fruiting varieties whenever possible. For instance, June-bearing strawberries would be at a lower risk than ever-bearing strawberries.
Another big part of my job is monitoring traps for three native moths in fields where produce is shipped to South Korea. The Korean government has strict protocols that need to be followed before fruit can be imported to make sure that no insect hitchhikers make it into their country and become invasive. We use delta traps with
pheromone lures to attract the adult moths. They get stuck to the sticky bottom of the trap and we can monitor the population level by counting them each week. It breaks my heart when I find incidentals like bumble bees who were trying to find shelter from rain stuck to the traps. Call me biased, but I feel less bad about sticking the yellow-jackets.