Spiders, for example, feed on many different hosts including other natural enemies. It is also very important that the natural enemy occur at the same time as its host. For example, if the natural enemy is an egg parasitoid, it must be present when host eggs are available. No natural enemy has all these attributes, but those with several characteristics will be more important in helping maintain pest populations. Conservation The conservation of natural enemies is probably the most important and readily available biological control practice available to growers.
Natural enemies occur in all production systems, from the backyard garden to the commercial field.
They are adapted to the local environment and to the target pest, and their conservation is generally simple and cost-effective. With relatively little effort the activity of these natural enemies can be observed. Lacewings, lady beetles, hover fly larvae, and parasitized aphid mummies are almost always present in aphid colonies. Fungus-infected adult flies are often common following periods of high humidity. These natural controls are important and need to be conserved and considered when making pest management decisions.