That question has probably occurred to every gardener in South Carolina who has seen his or her vegetables being consumed by insects that seemed to pop up suddenly, out of thin air.
 
Well, some insects actually do come out of the air, according to Randy Griffin, Clemson Extension entomologist. The fall armyworm is one. It arrives on winds from Florida as adult moths.
 
Other garden insect pests come out of the ground, from under the bark of trees and from trash in and around the garden.

Corn earworms rest over the winter as pupae several inches below the soil surface. When spring arrives, they come to the surface as adults through tunnels in the soil. They mate and lay eggs that hatch three days later as larvae, which begin feeding
on a wide variety of vegetables.

Cucumber beetles, stink bugs and certain aphids overwinter as adults in protected areas at the base of plants, under tree bark, and in wood and trash piles.

Other aphids spend the winter as eggs attached to host plants, in plant cracks or under tree bark.

Japanese beetles escape winter cold as grubs in the ground. They begin feeding on grass roots in March, form a cell and pupate. They emerge as adults in early June. If the weather has been dry for a while, they can be seen emerging in large numbers when rainfall softens the ground.

In the adult stage, Colorado potato beetles spend the winter several inches below the soil surface. They come out in spring, along with the first potato shoots. They mate, lay eggs and die.

Four to nine days later, small reddish larvae hatch and attack potato leaves. Two to three weeks later they move into the soil, turn into yellow pupae. About a week later adults emerge and lay eggs for a second generation.

Fire ants are unaffected by winter weather. As the weather gets colder, they simply go deeper into the soil to find a comfortable temperature for all their live stages: eggs, larvae, pupae and adults. When temperatures warm in the spring, they move back toward the soil surface and increase their foraging activities.

"No matter what the weather or the gardening practice, gardeners will never have a shortage of insects in the Southeast," said Griffin.