The Tachinid Fly: A Parasitic Fly With Pest-Control Potential

Some types of flies might be a bother with their stinging bite and buzzing voice. The Tachinid or “Diptera” species, on the other hand, is well worth inviting to your organic garden because of its ferocious appetite for garden pests such as Japanese beetles and grasshoppers.

  • Tachinid Fly Illustration
    Tachinid larvae feed internally on caterpillars, beetles, bugs, earwigs and grasshoppers. Adults feed on nectar, pollen and honeydew. 
    Illustration By Keith Ward

  • Tachinid Fly Illustration

This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.     

Tachinid Fly (Diptera)

There are more than 1,300 North American species of parasitic flies. Most resemble robust houseflies, but with short, bristly hairs on their rear ends. Tachinid flies are gruesome parasites of other insects. They employ a variety of tactics, with a common practice being to glue an egg onto another insect, so that the tachinid fly maggot can consume it as food. Other species of tachinid fly may lay mini-eggs on foliage being eaten by insects, which hatch in the insects’ bellies, or they may inject their eggs directly into another insect’s body with a sharp ovipositor.

Egg and larval development happen quickly in tachinid flies. Indeed, a quirk of many species is their ability to lay eggs that hatch almost immediately, or even before they are laid. Many tachinid fly species pass from the early stages to adulthood in just three to four weeks. If the host also moves through life stages quickly, several generations can be produced in one garden season. At the end of the season, some tachinid flies overwinter in leaf litter, while others spend winter inside the pupal cases of their victims.

Tachinid Fly Diet  

Tachinid flies feed on caterpillars, beetles, bugs, earwigs and grasshoppers. Garden pests likely to be impacted by tachinid flies include gypsy moths, cabbage worms, Japanese beetles, armyworms, cutworms, sawflies, codling moths, peach twig borers, pink bollworms, tent caterpillars, leafrollers and squash bugs. Adult tachinid flies feed on nectar, pollen and honeydew.

How to Attract Tachinid Flies to Your Organic Garden  

Tachinid flies can easily feed on the nectar of Queen Anne’s lace and other members of the carrot family. Attract tachinid flies by growing plants that bear umbels of flat florets, including carrots, cilantro, dill, coriander, buckwheat and sweet clover. Anise hyssop (Agastache) is also a favorite of tachinid flies.

More information about tachinid flies is available from the University of California, North American Dipterists Society, and the Agricultural Research Service.

7/11/2020 7:57:03 PM

Those shaking fingers at tachinid flies and seeking their destruction based on excessive, singular, and poorly researched opinions that they are wiping out monarchs need to take a step back and do more research. Like the study included in the 2012 American Entomologist "Tachinid Flies and Monarch Butterflies: Citizen Scientists Document Parasitism Patterns over Broad Spatial and Temporal Scales " by Karen Oberhauser. You see, yes, they kill some monarchs. But they are not driving them to extinction levels. There may local bouts in cycles. But to call for the destruction of these beneficial insects that help nature maintain balances so we aren't overrun by pests like the Mother Earth article points out, just isn't fair. Do the research, then live with nature, quit trying to control it. Tachinid Flies should not be killed.

2/27/2020 1:34:48 AM

Tachnid flies kills most monarch butterflies that are reared in backyards of America. They multiply quickly and wipe out entire populations of that season. Monarch butterflies are becoming endangered on the West Coast. Think twice before you kill your butterflies where you live! There are no known remedies once Tachnid have established their territory and will end up killing all our butterflies in America if they overpopulate.

8/22/2019 8:44:14 AM

could you please tell us what type of fly trap you use---do you make them or do you buy them. if so, where. thanks Jules.

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