Someone asked me recently whether I used pesticides in my garden.
I don’t, and I do.
These are my pesticides: Birds, wasps, yellow jackets and hornets, tachinid flies, robber flies, snipe flies, syrphid flies, dragonflies and damselflies, lady bugs, ground and tiger beetles, and spiders and opiliones.
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Birds … just a few of my helpers:
In spring, summer, and fall, and especially when nesting, insects, spiders, and other animal food make up 80-90% of most songbirds’ diets.
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Flying Insects:
>> Solitary wasps like the great black wasp (Sphex pensylvanicus) and the great golden digger wasp (Sphex ichneumoneus) eat nectar and/or pollen as adults, but capture and paralyze other insects for their larvae to feed on.
>> The larvae of thread-waisted wasps (Eremnophila aureonotata) feed on insects
>> Some yellow jackets, like this northern aerial yellow jacket (Dolichovespula norvegicoides), feed on larval and adult insects, feeding their larval children the chewed up meat
>> The bald-faced hornet (Dolichovespula maculata) eats nectar, fruit juice, sap, and insects
>> The northern paper wasp (Polistes fuscatus) feeds grasshoppers, caterpillars, and other insects to the larvae
>> The snipe fly (family Rhagionidae) may eat pollen and nectar or insects; their larvae feed on invertebrates, mainly insects.
>> Robber flies are notoriously aggressive predators, ambushing and feeding on other insects. This one is a Diogmites basalis, resting (or hunting?) on a juniper shrub:
>> The larvae of syrphid flies (aka hoverflies, flower flies) love aphids.
>> Dragonflies and damselflies are prodigious eaters of insects, including butterflies, moths, and bees as well as mosquitoes, midges, and other flying insects; below is a meadowhawk (Sympetrum) dragonfly with prey:
>> Tachinid flies, which lay eggs on caterpillars, beetles and bugs; when the eggs hatch, the young tunnel into their host and feed for a week or so, eventually killing the host insect.
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Other flying insectivores include preying mantises, which eat crickets, beetles, caterpillars, aphids, and leafhoppers, among others; lacewings (their larvae); and tiny predatory and parasitic wasps, which I see all over the garden but which are hard to photograph!
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Arachnids:
>> Opiliones (harvestman) arachnids eat a variety of insects and other arthropods, and also scavenge food from feces, fungi, etc.
>> Spiders, such as this dark fishing spider (Dolomedes tenebrosus) are notorious hunters of insects. This one is mainly nocturnal and hunts tadpoles and fish in addition to insects.
The other day, I noticed this candy stripe spider (Enoplognatha ovata) subduing an oriental beetle on bee balm:
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Beetles and others:
Some beetles, like the lady bug (family Coccinellidae), eat aphids, thrips, mealy bugs, mites, scale insects – anything with a soft body:
>> ground beetles, whose larvae develop in the soil and prey on slugs, root maggots, cutworms, etc.
>> adult tiger beetles, like this 6-spotted tiger beetle (which can fly, fairly low), eat small insects, spiders, and other arthropods, including other beetles, springtails, sawflies, caterpillars, flies, ants, and grasshoppers.
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Other beetles and non-flying insects that prey on pests include millipedes and centipedes, and assassin bugs (which can fly but not well), which eat beetles, flies, mosquitoes, caterpillars, and other insects and spiders.
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For more about beneficial insects in the garden, check out these links:
Plants that Attract Beneficial Insects, The Permaculture Research Institute, Oct. 2014. Excellent resource with images and info on the bugs and plant lists (with scientific and common names) for each.
Meet the Beneficial Insects, Organic Life, April 2011.
Enlist Beneficial Insects for Natural Pest Control, Mother Earth News, April/May 2012.
Beneficial Insects and Other Arthropods, Colorado State Univ. Extension, Feb. 2009.
And look at someone else’s bugs! at It’s Not Work, It’s Gardening in St. Louis, MO, 24 July 2015.