Controlling aphids organically is much easier if you encourage natural predators like hoverflies to take up residence in your garden. One natural pest management strategy for organic aphid control is to make your garden attractive to predatory insects. These can help keep aphid numbers and other sap suckers in balance – no chemicals needed.
The Hoverfly or Syrphid Fly (Diptera)
Also known as Flower Flies, hoverflies are members of the Syrphidae insect family. As their name suggests, adults often ‘hover’ like mini helicopters over nectar and pollen-rich flowers.
They lay their eggs near or in the middle of aphid colonies so when their babies hatch, dinner is served! Hoverfly larvae not only eat aphids but also soft bodied sap suckers like scale, mites, thrips and some small caterpillars. They are valuable predator insects to have in your garden as part of your organic pest management strategy.
How to Identify a Hoverfly
Like other flies, hoverflies have large bulbous eyes and yellow and black-banded abdomens. This colouring is why they are often mistaken for bees or wasps, as they mimic their striped colours.
Hoverflies imitate the appearance, sounds and behaviour of bees and wasps to help deter their predators. Even though they appear dangerous to their own predators, hoverflies are harmless and don’t sting or bite.
Though they look similar, hoverflies have 2 wings whereas bees and wasps have four. Bees are not able to hover in one spot like hoverflies – they are too busy flying from flower to flower. Hoverflies can also dart back and forth and fly very fast.
A hoverfly’s antennae are usually short and in the centre of its head, whereas wasp antennae are more like bullhorns that stick out on the sides of the head. Wasps also have a distinctive narrow ‘waist’ and rounded abdomen, whereas the hoverfly’s body is flatter.
An adult hoverfly will hold its single pair of wings out to the side of its body when resting. However, a wasp will fold its wings along its body when at rest.
Hoverfly larvae look very similar to other pest caterpillars like diamondback moth. It’s worth learning to identify who’s who before you squash insects, in case you’re killing a friend rather than the enemy!
Beneficial Role in Pollination and Pest Control
Adult hoverflies are major pollinators of some flower plants and a valuable insect to have in our home gardens. After bees, hoverflies are considered the next most important pollinator.
Hoverflies also play an important role in home gardens as a predatory insect in its larval stage of life. The young hoverfly maggots rely on herbivores like aphids, scale and other soft-bodied insects for food.
What do Hoverflies Eat?
Adult hoverflies eat nectar and pollen from flowers, including food crops. This food source provides the adults with energy and the nutrients they need to reproduce. The adults don’t eat aphids.
Many adult hoverfly species feed on the honeydew secreted by aphids – providing an awesome free service to gardeners! When they suck up this sticky sugary substance from leaves, this helps prevent black sooty mould.
Organic Aphid Control – Hoverfly Larvae
Hoverfly babies (or larvae) are known as maggots and some species have ferocious appetites for aphids. I’ve watched them in my own garden gobbling these sap suckers and it’s an amazing sight to behold. They suck the juices out of the aphid’s body!
Hoverfly larvae can control 70 – 100% of the aphids around them. Adults will raise their families on plants that are infested with aphids and lay the number of eggs according to the aphid population!
How to Attract Hoverflies to your Garden
Don’t expect to have a pest-free garden even if hoverflies are in residence. Their young and the babies of other beneficial pest-controlling insects like ladybirds and predatory wasps, need to eat aphids as part of their life cycle!
Research studies indicate hoverflies are attracted to the honeydew that large aphid colonies produce. The adult hoverflies target the affected plants to raise their families and the larvae keep the aphid population in balance.
If you don’t have any aphids present, these insects have nothing to eat! They can however, help maintain an ecological balance in your garden.
“We need to stop thinking about aphids as the enemy and instead, as a food source for beneficial predator insects. If you have too many aphids, you have an imbalance of not enough predators!”
To encourage pollinators and predator insects like hoverflies into your garden, avoid using chemicals or pesticides.
Which Flowers are Best for Hoverflies?
The easiest way to attract hoverflies is to plant a diverse range of flowers and flowering plants.
Some of the best flowers to attract hoverflies are yarrow, Queen Anne’s lace, cornflowers and flowers in the Umbellifer family that we met in last month’s newsletter. These include flowers of parsley, carrots, celery, coriander, dill and fennel.
According to one research study, some species of hoverflies prefer yellow and white coloured flowers. Research studies have also found sweet alyssum and buckwheat flowers are particularly attractive to hoverflies.
So why not plant a few of these to invite hoverflies to your garden?
- Imitate Nature for Higher Yields and Less Pests
- How to Prevent and Get Rid of Aphids Naturally
- 13 Benefits of Growing Flowers in your Vegetable Garden
- How to Control Garden Pest Insects Naturally
- Organic Fruit Fly Control Strategies
- 4 Steps to Improve Pollination and Your Harvests: Part 1
- 4 Steps to Improve Pollination and Your Harvests: Part 2
- Hover Flies – Family Syrphidae
- Flower Flies & Other Biological Control Agents for Aphids in Vegetable Crops
- Hoverfly preference for high honeydew amounts creates enemy-free space for aphids colonizing novel host plants
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© Copyright Anne Gibson, The Micro Gardener 2018. https://themicrogardener.com. All rights reserved.
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