ladybug,lacewing and certain mites are common predators of insects. Some tiny wasps and some fly species are parasites of insects. Many beneficial parasites are host specific and do not control a wide range of pests. Parasites and predators are often very effective at keeping insect pests at low levels. For example, aphids, scales, and mites rarely bulid to damaging levels in pine or spruce forest because their populations are controlled by predators and parasites. Insects are also affected by a variety of bacterial, fungal, and viral diseases that affect only insects.