Managing ‘pests’ without pesticides

ABOVE: A praying mantis. Photo: David Clode on Unsplash

Bernice Shepherd

One of the biggest frustrations for gardeners is seeing an abundant crop of delicious spring vegetables or luscious fruit devastated by pests.

Often the first reaction is to buy a spray that kills pests then smother them in it.

You could buy chemical sprays and be forever squirting insects in your garden.

But apart from costing you money and killing a lot of beneficial insects, this method is guaranteed to prevent your garden becoming a healthy, functioning ecosystem.

An infestation of pest insects is an indication that all is not well in your patch.

A few aphids on your prized roses are not going to kill them.

Hello ladybirds. Photo: Bernice Shepherd

However, if you get aphids in such great numbers that your plants are under threat, then it is perhaps time to look at what is not working.

In a healthy ecosystem the plants and animals keep each other in check so there is less need for intervention.

When I inherited my garden there was nothing but grass, an orange tree and two mango trees – very little diversity.

The orange was infested with stinkbugs, slugs everywhere were eating my seedlings and my first crops were decimated by grasshoppers.

Six years on, my garden is a riot of diversity after planting more than 100 perennial plants and still adding.

To some, it may indeed look more like a riot than a garden – but I no longer have pest problems.

Yes, I get the odd stinkbug and a few aphids, but these are invariably dealt with by birds, ladybugs, lacewings, dragonflies, damselflies, praying mantises, the carnivorous blue planarian worm (often mistaken for leeches) and numerous and diverse spiders.

Not a leech. Photo: Bernie Shepherd

That is not to say I will never have pest problems – fruit fly claimed an entire orange crop last year – but an abundance of wildlife generally keeps any potential pests in balance.

So how to encourage more wildlife and more beneficial bugs?

Stop killing the bugs

Insects such as sap-sucking aphids are often seen on new young growth in spring. They are protected by ants who ‘farm’ them for the honeydew they produce.

But aphids are not only a food source for ants – they feed a myriad of beneficial bugs such as  the larvae of ladybugs, lacewings, hoverflies, parasitic wasps and spiders.

Bees sometimes feed on the honeydew.

Hoverfly. Photo: Joana Pires on Unsplash

So if you spray or kill the aphids, you are removing the food of other creatures.

Harlequin beetles or stinkbugs can become a problem on citrus here in the subtropics.

Keeping fruit trees pruned and open allows in light and air, which not only invigorates the tree, it allows birds and other insects to see what food is in there and get at it.

Gardeners often reach for the spray when they spot a caterpillar.

But if you leave them alone and observe, you’ll find that birds will pick them off over the space of a week or two until they are gone.

And it’s worth remembering that no caterpillars means no moths or butterflies…

Encourage diversity and companion plant

Monocultures encourage disease and pest attack.

One whole row or whole bed of one type of vegetable, say brassicas, will be an open invitation to the white cabbage butterfly to lay her eggs. Very soon your bed of broccoli and brussels sprouts will be alive with her cute little offspring happily munching through your food.

Instead of planting a whole row or a whole bed of one thing, mix it up a little bit. Look into companion planting and find out what grows well with what.

Brassicas love herbs and onions. Onions protect them against cabbage moth by confusing them with their smell.

Plant some carrots and marigolds in with your tomatoes.

Carrots and tomatoes love growing together and don’t compete for nutrition.

Marigolds ward off soil pests such as nematodes that feed on tomato roots.

Herbs are a great companion for most vegetables as they have strong fragrance which confuses insects and disguises the smells they are looking for.

Mixing it up in the garden bed. Photo: Bernice Shepherd

Plant flowers in your garden

It cannot be said often enough – plant flowers in your garden.

Natives, exotics, wildflowers, weed flowers.

All flowers will bring in a wide array of beneficial and predatory insects – bees, ladybugs, hoverflies, lacewings, parasitic wasps and carnivorous beetles.

And with the insects come birds, frogs, native toads and lizards, all of which eat insects – including mosquitoes.

Some flowers attract insects and others attract birds with their nectar.

Nectar-eating birds will also eat any protein source they happen upon that is the right size, so all flowering natives will bring an abundance of insect-eating birdlife into your garden.

Keep your plants healthy

Healthy plants resist attack. Stressed plants invite pests.

With hindsight, it is no surprise my orange was attacked by fruit fly.

I had become neglectful of it for some time and it needed pruning, feeding and proper watering.

Having left it to its own devices, I discovered at a late stage that I had fruit fly.

By the time I got the traps up, it was too late, and the crop was lost.

Part of keeping your plants and trees healthy is regularly wandering around in your backyard sanctuary and keeping an eye on things.

White crab spider in my lemon tree. Photo: Bernice Shepherd

If you spend five minutes in your garden every day, you will notice changes and you will see when something needs some love.

So, satisfy your plant addiction and get more diversity in your garden, spend time in your favourite place and watch the wildlife.

You never know, you may never have to spray again.

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