The smallest pests are inherently the hardest to control in a conventional yard or farm, yet they can be easily managed in a naturally managed landscape that makes their predators comfortable and lets them breed.
An infestation of any pest is a feast for any predator that eats it. Given a chance to do their job, predators multiply as they feast, and the population of the pest crashes back to pre-infestation levels. In a natural landscape, any infestation is a temporary affair. When ladybugs and soldier beetles home in on aphids on roses, they don’t last long.
Three things make insect predators comfortable: shelter; food; and water. The shelter for many predators is leaf mulch; coarse bark works as well. Adults and/or larvae crawl around under the mulch, eating whatever they can kill. At night, many crawl out of hiding and stalk their prey on the plants. Ground predators include soldier beetle larvae, ground beetles, ants, spiders, centipedes, and even earwigs, which eat fungus-infected leaves, not healthy plant tissue.
Since insects have little sugar or fat, their predators need an energy source like nectar, and many of them, like parasitic wasps and soldier beetles, prefer small flowers, the smaller the better. Carrot flowers qualify, as do chickweed and purslane, chickweed in spring, purslane in summer. Both of these low, spreading annuals are useful and edible, and don’t bother other plants much. Deadhead your carrot flowers; they are likely to make half-wild seed that makes white, skinny roots.
Water is needed as well. If you buy ladybugs or spider mite predators, it is important to water the tops of the plants so they can take a first drink. Bees, wasps and birds mob sources of water in hot, dry weather. Spider mites love dryness and shun humidity. Sprinkler irrigation and misters are best for providing the water that your predators need, along with baths and fountains for birds.