Hover flies (also called flower flies or syrphid flies) are often mistaken for bees or wasps because of their yellow-and-black stripes, but they are harmless to humans and hugely beneficial in the garden. This guide explains the main reasons hover flies are good, how to attract them, and how to tell them apart from stinging insects.
What You’ll Need
- A garden or outdoor space with flowering plants
- Patience to observe insects (hover flies are small and fast)
- Optional: a magnifying glass or camera with zoom to see details
Step-by-Step
- Understand what hover flies do. Adult hover flies feed on nectar and pollen, making them excellent pollinators. They visit a wide range of flowers, similar to bees, and help fertilize plants as they move from bloom to bloom.
- Recognize their larvae are predators. The larvae of many hover fly species are voracious eaters of aphids and other soft-bodied pests like scale insects and thrips. A single larva can consume dozens of aphids per day, providing natural pest control without chemicals.
- Learn to identify them. Hover flies have a single pair of wings (bees and wasps have two pairs), short antennae, and large eyes that take up most of their head. They often hover in mid-air, hence the name, and can fly sideways or backward. Unlike bees, they do not have a stinger and are completely harmless.
- Check for their presence in your garden. Look for adult flies hovering near flowers, especially in sunny spots. Their larvae are small, legless maggots that are often green or brown and can be found on leaves where aphids are present.
- Plant flowers to attract them. Hover flies are drawn to small, open flowers with accessible nectar and pollen. Good choices include alyssum, coriander, dill, fennel, marigolds, and many herbs. Plant a variety that blooms from spring to fall to provide a continuous food source.
- Avoid broad-spectrum insecticides. Pesticides kill hover flies along with pests. Use targeted methods like insecticidal soap or simply wash off aphids with water to preserve the beneficial insects.
- Provide habitat for larvae. Some hover fly larvae live in decaying organic matter or water, but most garden species are aphid predators. Leaving some weeds like wild mustard or dandelions can provide extra nectar sources for adults.
- Observe the results. Over a few weeks, you should see fewer aphids on your plants and more flowers setting fruit, thanks to the pollination services of hover flies.
Common Mistakes
- Killing hover flies because they look like wasps. Many people swat or spray them, not realizing they are beneficial. Learn to spot the single pair of wings and the hovering behavior.
- Using pesticides that harm them. Even organic pesticides can kill hover flies if applied when they are active. Always spot-treat and spray in the evening when pollinators are less active.
- Planting only showy double flowers. Double blooms often lack nectar or are too closed for hover flies to access. Stick to simple, open flowers.
- Expecting instant results. Hover flies take time to find your garden and build their population. Be patient.
Tips
- Plant in clusters rather than single plants; hover flies are more likely to notice a patch of flowers.
- Include plants with different flower shapes and colors, especially white and yellow, which are highly attractive.
- Provide a shallow water source, like a dish with pebbles, so adults can drink without drowning.
- Leave some aphid colonies alone for a few days; hover fly larvae need them as food. If aphids are out of control, wash them off with a strong stream of water.
- Learn to recognize hover fly eggs: they are tiny, white, and laid singly near aphid colonies.
Troubleshooting
- No hover flies seen: If you don’t see any, it may be too early in the season or there may not be enough flowers. Add more nectar-rich plants and wait a few weeks.
- Aphids still increasing: Hover fly larvae may not be present yet, or the aphid population is too large for them to control. Use a gentle soap spray on the worst infestations, but avoid treating the whole plant.
- Confused with wasps: If you’re unsure, watch the insect’s behavior. Hover flies hover and dart; wasps fly in a more direct, purposeful way. Also, hover flies don’t have a narrow waist like wasps.
- Hover flies disappearing: They may have moved to a better food source nearby. Ensure a continuous bloom by planting a succession of flowers.
Frequently Asked Questions
Do hover flies sting or bite? No. Hover flies have no stinger and no biting mouthparts. They are completely harmless to humans and pets.
Are hover flies the same as sweat bees? No. Sweat bees are a type of bee and can sting (though mildly). Hover flies are flies and cannot sting. They are just mimics.
What do hover fly larvae look like? They are small, legless maggots, often green or brown, that blend in with leaves. They can be found on plants with aphids.
How many aphids does a hover fly larva eat? A single larva can eat dozens of aphids per day, but the exact number varies by species and size.
Can I buy hover flies for my garden? Some suppliers sell them, but it’s usually more effective to attract wild ones by planting the right flowers and avoiding pesticides.
Do hover flies pollinate vegetables? Yes, they visit many vegetable flowers, especially those in the carrot family (like dill and fennel), and can help increase fruit set in some crops.