What do theylook like? Their are many different insects, and insect treaments. Are they like little spiders, or do the fly? What can you tell us about them. You need to treat the right insect with the right treatment.
Bugs come with alot of cheaper soils. The bug your mostlikly having is the Leafminer.
Leafminers are housefly-like flies and about the size of fruit flies. Sound about right ? If so, do a search on them on yahoo or something. Alot of sites will list what types of sprays to use.
.how wet is your medium?...could be fungus gnats....
Adult fungus gnats are dark, delicate-looking insects, similar in appearance to mosquitoes. Adult fungus gnats have slender legs with segmented antennae that are longer than their head. Although a few species are up to 1/2-inch long, adults commonly are about 1/16 to 1/8-inch long. Wings are light gray to clear; the common Bradysia species have a Y-shaped wing vein. Fungus gnats are relatively weak fliers and usually are not found flying around indoors. They generally remain near potted plants and often run or rest on growing media, foliage, or litter.
Females lay tiny eggs in moist organic debris or potting soil. Larvae have a shiny black head and an elongate, whitish to clear, legless body. They eat organic mulch, leaf mold, grass clippings, compost, root hairs, and fungi. If conditions are especially moist and fungus gnats are abundant, larvae can leave slime trails on the surface of media that look like trails from small snails or slugs.
fungus gnats commonly damage plants. Larvae of these flies feed on roots, thus stunting plant growth. Root damage can occur in interior plantscapes and in houseplants if high populations infest moist, organic-rich soil. Fungus gnat larval damage can be especially serious in greenhouses, nurseries, and sod farms. In addition to larvae chewing on roots, both larvae and adults can spread plant pathogens and may promote disease in commercial crops.
A layer of dry sand about an inch deep aids in deterring them from laying eggs and incubation. Another excellent product for ANY crawling pests is "Diatomaceous Earth".
It is totally organic and safe to use even in late flower, as it is not applied to the plants foliage or absorbed by the plant. It is comprised of seashells crushed to microscopic particles that lacerate the insects soft outter shell,causing death by dehydration.