Ongoing research

Insects – they’re everywhere! With nearly a million named species, they make up about 90% of all species of animals on the planet and more than half of all living things on Earth. Yet it is estimated that only about one to three percent are truly harmful. Most insects go about their daily business pollinating plants, helping decompose dead material, or ending up as meals for birds, fish, and other creatures – part of nature’s food chain. One big service that a number of insects provide, hidden from most of us, is keeping pest populations down - the good bugs battling the bad ones.  

Natural enemies, also known as beneficials, biological pest control, and good bugs, are the predators that attack, kill, and feed on their prey, the parasites that feed on or inside other insects, killing their hosts, and the pathogens (disease-producing organisms) that can infect and kill the host. While the majority of beneficials are insects, there are also spiders and mites (arachnids), nematodes, and a wide range of microbes. 

Getting to know the good guys is the first step in effective biological pest control. Some common beneficials you may find in the garden include:

• Ladybugs, the rotund little reddish-orange beetle adult and the larval stage, looking like a small alligator, are both predators with enormous appetites.
• Green lacewing adults, the ethereal-looking insects with a slender pale green body and immense golden eyes, aren’t predators at all, feeding on pollen and nectar. But their immature form, also resembling tiny alligators, is a very aggressive predator.
• Soldier beetles are predators of aphids and other soft-bodied insects. Adults are straight-sided beetles about one-half inch long with a red, orange, or yellow head and abdomen.
• Syrphid flies, also known as hover flies, resemble bees. The brightly colored adults are black or brown with yellow-banded abdomens and body markings. Their caterpillar-looking larvae are the predators. Adults feast on pollen and nectar and are considered an important pollinator.
• Spiders are major predators in the garden; some capture prey in silken webs, while others stalk insects across the ground or vegetation or lie in wait and pounce on prey.

Encouraging beneficials in your garden is about the greenest method of pest control you can use.  Like any living creature, these good guys need food, water, and shelter, all generally available in the garden. 

 Here are some ways to attract and keep them around:

• Use diverse types of plants - natives, annuals, perennials, and herbs- to encourage a range of beneficials.
• Use sequentially flowering species to provide nectar, pollen, and shelter throughout the growing season.
• Include plants with many small flowers; they are preferred by many beneficial insects over those with large, single flowers.   
• Create plantings of varied heights in sun and shade to provide food and habitat for different insect species and life stages.
• Maintain groundcovers and coarse mulches for non-flying predators to hide from their enemies.
• Provide water - a shallow dish of water filled with pebbles or gravel and placed in a sheltered area will give small beneficials a safe place to slurp.
• Tolerate low populations of plant-feeding insects and mites so that food is available for the predators.
• Go light on fertilizer; lush new plant growth encourages sucking pests like aphids to reproduce more rapidly than natural enemies may be able to control.
• Avoid the use of pesticides – they don’t discriminate between good and bad bugs.  

These families of plants are attractive to multiple life stages of numerous beneficial insects:

• Carrot (Apiaceae): cilantro, dill, fennel, and Queen Anne’s Lace
• Aster (Asteraceae): coneflower, coreopsis, goldenrod, sunflower, and yarrow
• Bean (Fabaceae): alfalfa, fava bean, and sweet clover
• Mustard (Brassicaceae): mustards and sweet alyssum
• Verbena (Verbenaceae): lantana and verbena

Providing the basics of food, water, and shelter to natural enemies in your garden is pretty easy and has a terrific payback by helping to keep pest populations at a tolerable level.  

By Nanette Londeree, September 6, 2025