A plague is among us. The people of Warren County have noticed sticky residue coating their cars and outdoor areas, and a storm of tiny, white insects.

The culprit is the wooly aphid, Warren County Extension Agent Anna McCain said.

“There are several different types of aphids, and this particular aphid is the Asian wooly hackberry aphid,” she said.

McCain said the aphids are relatively new to the area and are not native to Mississippi.

“It’s normal to see very large populations of them coming in cycles,” she said. “We’re seeing a lot of them floating around out there, and that’s normal.”

McCain said she suggests that people just deal with the aphids for a little while and they will be gone again.

“They have a peak in their cycle in August and September,” she said. “You’ll see really large populations in August and September. The cycle will die out when it starts to cool down in late September.”

Other than annoyance, wooly aphids typically don’t cause much damage, McCain said.

“Aphids in general, the way they damage trees is they actually suck the plant sap out of trees,” she said.

The wooly aphid is only a host on hackberry trees, McCain said.

“A lot of times people will see them resting on other plants,” she said.

“That doesn’t mean they’re feeding on those plants, they’re just in transition.”

McCain said the aphids could cause damage, mostly in the form of carrying pathogens from tree to tree.

“They have what’s called a piercing and sucking mouth part,” she said. “When they take that and they stick it down in a leaf they can contract a pathogen, then when they go to the next tree they’ll spread the disease.”

Sooty mold often appears in black patches on leaves where the aphids have been, McCain said.

“When they take the plant sap, they produce this stuff called honeydew, which comes from them eating then going to the bathroom,” she said. “That sticky honeydew is a great habitat for sooty mold.”

The honeydew is the annoying, sticky residue many people in the area have been finding on their vehicles and outdoor spaces.

“In severe, severe cases, it could block photosynthesis enough that the plant could weaken, but typically, it get’s some sooty mold on it, we get a heavy rain, and it will take care of itself on its own,” McCain said.