Spoiler Alert – That’s Not Pecan Tree Sap on Your Car
I don't know about you, but I see a sticky substance on my truck all the time. For years, I've always thought it was "pecan tree sap". I mean, it's always happened when my truck was under, or near, a pecan tree. So, I just assumed it's sap from the tree.
Come to find out, that's not what it is at all. It's actually the excrement of a little bugs called yellow aphid complex and black pecan aphid. Instead of calling it bug poo, someone came up with a more appetizing name for that sticky substance - honeydew.
Regardless what you call it, it's bug poo, it's sticky, and it gets all over my truck - every day.
So, instead of cutting your, or your neighbor's, pecan tree down, you can simply treat the tree to help prevent the aphids from causing that sticky mess.
One method is to plant cover crops around the base of your tree. Clover, alfalfa, sainfoin, and hairy vetch are options to plan as these help support a variety parasitoid and predator species that can help reduce your aphid population.
Parasitoids and predator species are known as “beneficials” because they consume the insects that do damage in your orchard. In this case, as the cover crop blooms throughout the season, aphids will increasingly draw lady beetles. If you get a buildup of your targeted pest, you can also cut your cover crop and drive the beneficials into the trees and surrounding area. [Noble Research Institute]
Another method is to spray the tree with neem oil or insecticidal soaps, but you'll have to, basically, spray the entire tree's foliage as it's mainly beneficial when it comes in contact with the aphids. The upside to this is that it won't harm beneficial insects.
You can also use a systemic pesticide to control your local aphid population, but some pesticides can also kill your beneficial insects, so choose one that contains Imadacloprid. Products with Imadacloprid will kill the aphids, but won't harm your local pollinators like bees, hummingbirds, and butterflies. Just be very careful when choosing an pesticide for controlling aphids, as many can do more harm than good.
Once you've eradicated those aphids, and their sticky poo, you'll want to consider some preventative maintenance. One way to prevent aphids from returning is my employing beneficial bugs, like lady beetles and lacewings, as they love to dine on aphids.
If, after all of your research, you've found that nothing works, then just park a little further away from that pecan tree.