The bloodsucking, no-good, no-see-um bug is back in Yolo County.
No-see-ums, or Valley black gnats, are biting and sucking the blood of residents from Davis to Woodland, causing red, itching welts that take two weeks to heal.
The Bohart Museum of Entomology at the University of California, Davis, is fielding dozens of calls and emails about the nearly invisible insects causing so much pain.
"The adults are emerging in large numbers now and need blood so residents need to beware of grassy areas that cover alkaline clay soils," said Lynn Kimsey, director of the Bohart Museum of Entomology in a university press release. "These insects are ferocious biters. Even though they don't spread any diseases, they are sufficiently annoying to keep people indoors in some areas of California."
The no-see-um is smaller than a flea and is prevalent on the west side of the Sacramento Valley, including Davis and Woodland where there are alkaline clay soils. Adults emerge in the spring when the soil begins to dry and crack.
The larvae can stay in the soil in a kind of hibernation for three years or longer before the flies emerge to breed as they are this year. When humans sit on lawns with clay soil underneath in Yolo County, the emerging flies can bite with ferocity, experts said.
Like mosquitoes, only the female bites. The critters need a meal of blood to complete their reproductive cycle.
The no-see-um injects saliva in its human or animal victim, which causes blood to pool just under the skin surface. Although the bite doesn't hurt, within 12 hours the flat red spot really starts to itch.
But don't scratch, warns Kimsey. That will only prolong the suffering.
They remain a pest for several weeks. Avoid being bitten by not sitting long on grass.
And one more thing, she notes. Repellants don't work.
Call The Bee's Bill Lindelof, (916) 321-1079. Follow him on Twitter @Lindelofnews.