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 pests in the garden is quite normal. When most pests are in large enough numbers, they can do real damage to some of our plants, but 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, in particular crops.
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.
There’s loads of examples, but here’s some of the most recognisable beneficial insects that help us in the garden:
Ladybird.
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. 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 in my garden in Perth.
Hoverfly.
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.
Praying Mantis.
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.
Lacewing.
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.
Robber Flies.
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 (not insects but beneficial).
Spiders 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.
Wasps.
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.
These are so important for a flourishing vegetable patch. Plant lots of flowering plants to help attract them and feed them.
How to attract beneficial insects:
Many beneficial insect adults either feed exclusively 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, into larger shrubs and small trees, through to larger tree canopies, offering 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, plenty of rocks, some bare patches of soil, some logs and remember to include a water source. 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:
Here are some of my favourite plants (from those I grow) 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.
Alyssum. Hoverflies, Lacewings, Ladybirds, Parasitic Wasps.
Bergamot. Bees.
Borage. Bees, Butterflies.
Buckwheat. Hoverflies, Ladybirds, Predatory Wasps.
Buddleja. Bees, Butterflies.
Calendula. Bees, Butterflies, Lacewings, Ladybirds, Hoverflies.
Caraway. Ladybirds.
Chamomile. Hoverflies, Wasps.
Chervil. Bees, Parasitic Wasps.
Clover. Bees.
Cosmos. Hoverflies, Lacewings, Ladybirds, Parasitic Wasps.
Dandelion. Bees, Butterflies, Hoverflies.
Dill. Ladybirds.
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.
Nasturtium. Hoverflies.
Pride of Madeira. Bees, Butterflies.
Queen Anne’s Lace. Bees, Lacewings, Ladybirds, Hoverflies, Small Wasps.
Rosemary. Bees.
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.
