Remove excess grass, leaves, firewood, and clippings from your yard. Mosquitos like dark patches of foliage because it serves as a place for them to rest, according to Shannon Bennett, a microbiologist at the California Academy of Sciences. Turn over larger yard items like children’s toys, which could hold water. Take special note of tarps, too. If they’re not stretched over firewood piles or boats tightly, they’re probably holding water.