It's Raining... Sugar?Honeydew is a sugary secretion produced by plant feeding insects like aphids and scale insects. While sucking up the sugary plant sap, they excrete the excess sugar as little droplets from their back end. When there are a lot of aphids, the honeydew can rain down and build up a sticky film on surfaces below the aphids…yuck! The honeydew can coat the leaves underneath the aphids, which causes a black fuzzy mold to grow all over the leaves. And if you are unfortunate enough to park under a tree covered in aphids, you might be in for a sticky surprise a few hours later when you find a layer of honeydew on your windshield.
Many insects like to take advantage of this free, sugar rich meal. Ants will actually herd aphids like cattle and protect them from predators in exchange for getting to feed on the honeydew. In the fall, wasps, yellowjackets, and many other social Hymenopterans abandon their nests and spend their remaining days feeding, and will sometimes be seen aggregating together on trees where aphids are present to enjoy the honeydew.
Aphids feed on many different plants, and can be different colors depending on their species (green, yellow, or even black). Keep an eye out for them on your priceless rose bushes or beautiful maple tree!