Swarms of the insects have been reported in northwest Solano County, the Marysville area and the Sacramento County town of Herald.
People have been sending pictures to UC Davis Entomologist Steve Heydon.
"Each square foot might have 25 to 30 or 50 grasshoppers on it, so it's pretty incredible. This year seems to be a particularly good year for the grasshoppers."
Heydon says it's possible that the grasshoppers laid a lot of eggs during the previous two wet winters. Now, a larger-than-normal population is searching for food that's harder to find because of this past dry winter.
"So once they've kind of gone through the good grass and stuff, then they start migrating."
So far, the bugs haven't ruined any crops…just some backyard gardens.
Grasshoppers only live about a month or so. Heydon predicts the insect problem will be over by mid-July.