If you’ve heard the term ‘beneficial insects’ and you’re not too sure what it means, here’s a basic explanation along with some tips on how you can attract them into your garden.
All insects have a role to play in the garden and having insect 'pests' in the garden is quite normal. When these pests are present in large enough numbers, they can do real damage to some of our plants.
However if we get the balance right by providing food sources and homes for different insects (and birds) who eat them, you might be surprised at how brilliant nature can be at sorting things out with only minimal damage being caused to your plants and food crops.
What are Beneficial Insects?
The insects that help with pest control and pollination (and aeration of the soil, among other things) are generally referred to as beneficial insects.
This term is subjective of course, as we tend to encourage those insects that offer us a service instead of the ones that destroy our plants, damage our lawns and invade our homes.
Beneficial Insects That Help Us in the Garden
There’s loads of examples, but here’s some of the most recognisable beneficial insects that help us in the garden:
These much-loved beetles are amazing predators of aphids, mealybug, mites, and soft scale insects. An adult ladybird can eat thousands of aphids during its life. Ladybird larvae are ferocious eaters of aphids.
Adult ladybirds are attracted to nectar rich flowers such as Tansy, Cosmos and Scented Pelargoniums.
There are over a hundred species known in Australia including four common garden species. One of these garden species (Epilachna vigintioctopunctata) is a plant eater but I haven’t seen it yet in my garden in Perth.
These small flying insects can sometimes be mistaken for bees.
Just observe the way they hover, then dart off and you’ll be able to easily identify them by their flight. They are often visible in large numbers during the warmer months and they have a life cycle of about one month.
They are one of the best pollinators in the garden and their larvae are superb aphid munching machines. The larvae are also brilliant at eating caterpillars, thrips and scale.
If you have aphids, instead of spraying, check first to see whether any slug-like larvae are nearby making a b-line for their next meal.
An insect that pollinates and eats pests is definitely one you want in your garden. Help attract them by having native vegetation and flowers. They are attracted to yellow flowers in particular so try planting Calendula and Marigolds.
Often seen in the warmer months, these amazing predators feed on soft bodied insects including aphids, caterpillars and mealybugs.
Mantis are highly intelligent, solitary insects and they seem to have a fondness for plants such as Fennel and Goldenrod due to the smaller insects that are attracted to these plants.
These nocturnal insects prey on aphids, mealybugs and small grubs (among others). They have large wings but are fairly weak flyers and only manage a few metres at a time.
The larvae are daytime predators, feasting on numerous small insects that target vegetables and roses.
These fierce predators capture their prey during flight. They hunt flies, grasshoppers and moths (among others). The larvae are also hungry predators, eating a variety of insects on the ground.
A well planted garden with height vantage points, can help attract them. So too can plants such as Marigolds, Caraway, Calendula and Sunflowers.
Spiders are not insects but they are certainly beneficial and play an important part in our gardens.
Many are excellent at capturing flies and mosquitoes and some spiders can eat thousands of them in their lifetime.
Predatory wasps hunt all kinds of insects, including citrus leaf miner, caterpillars and grubs (among others).
Some wasps lays their eggs in or on living caterpillars, beetles, scale, flies and aphids.
Bees are so important for a flourishing vegetable patch and they are the cornerstone in preserving ecosystem health.
Plant lots of flowering plants to help attract them and feed them.
How to Attract Beneficial Insects
Many beneficial insect adults either feed exclusively on, or supplement their diets, with nectar and pollen.
Incorporate a wide variety of flowering plants with different flower shapes, sizes, and colours and ensure different plants flower across the year. This will help create diversity in your garden.
Offer different height levels of plants, from low ground covers up to waist-high grasses and small shrubs. Larger shrubs, small trees and the formation of larger tree canopies offer different leaf sizes and shapes, and different bark types too.
Create natural environments where different types of insects can make their homes and allow leaf litter to remain on the ground. Add plenty of rocks, some bare patches of soil, some logs and remember to include a water source like a shallow bowl or bee bath.
As you create more diversity in your garden, you’ll most likely notice changes taking place, such as the appearance of insect eating birds, which can play a big role in keeping pest numbers under control. Ensure you take the time to observe your garden and the life that frequents it or calls it home.
Plants That Help Attract Beneficial Insects
Below are some of my favourite plants for attracting beneficial insects into the garden with a rough guide to the insects they may attract.
It’s really important you allow them to go to flower. There’s loads more plants that are ideal so don’t feel limited to this list. You generally can’t go wrong with plants from the Apiaceae or Asteraceae families.
A bee bath among Cosmos Flowers
Flowering Plants and the Beneficial Insects They Attract
Alyssum: Hoverflies, Lacewings, Ladybirds, Parasitic Wasps
Borage: Bees, Butterflies
Buckwheat: Hoverflies, Ladybirds, Predatory Wasps
Buddleja: Bees, Butterflies
Calendula: Bees, Butterflies, Lacewings, Ladybirds, Hoverflies
Chamomile: Hoverflies, Wasps
Chervil: Bees, Parasitic Wasps
Cosmos: Hoverflies, Lacewings, Ladybirds, Parasitic Wasps
Dandelion: Bees, Butterflies, Hoverflies
Echinacea: Bees, Butterflies
Fennel: Bees, Butterflies, Lacewings, Ladybirds
Feverfew: Hoverflies, Ladybirds
Goldenrod: Bees, Butterflies
Lavender: Bees, Butterflies, Hoverflies
Lemon Balm: Parasitic Wasps
Madeira Sage Germander: Bees
Marigold: Bees, Butterflies, Hoverflies, Ladybirds
Mugwort: Butterflies, Hoverflies, Lacewings, Parasitic Wasps
Pride of Madeira: Bees, Butterflies
Queen Anne’s Lace: Bees, Lacewings, Ladybirds, Hoverflies, Small Wasps
Rudbeckia: Bees, Butterflies
Sage: Bees, Butterflies
Shasta Daisy: Bees, Butterflies.
Sunflowers: Bees, Butterflies
Tansy: Lacewings, Ladybirds
Thyme: Bees, Hoverflies
Wormwood: Butterflies, Hoverflies, Lacewings, Parasitic Wasps
Yarrow: Hoverflies, Ladybirds, Parasitic Wasps
Embrace the beneficial insects. Love them and nurture them and you’re bound to see the helpful impact they’ll make in your garden.
About the Author - Andrew Osenton
Andrew Osenton started the Kalamunda Plant Company in 2018 and specialises in growing edible and medicinal plants. He is also very proud to produce the Sabrina's Selection of plants for Sabrina Hahn - all of these plants are grown in coir pots and he uses no pesticides, fungicides or herbicides. Order from his extensive range of unusual plants online or see him at the Kalamunda Garden Festival, a free community event he runs in the Perth Hills.