Instead of chemicals, why not use plants’ neighbours to help you beat the bad bugs this summer, says Adrienne Wild
Even though the good weather means plants are growing fast and strong now, they can still be prone to pest attack by garden bugs.
Keeping them healthy by regular watering, feeding and grooming will improve their ability to fight off pests before they incur major damage. For vulnerable plants like roses and veggies, you may need to take other precautions. Natural predators, like ladybirds, hoverflies and lacewings, as well as tapping into the power of plants, could be the answer.
Good bugs like these will gobble up bad garden bugs and can be encouraged by growing plants, such as Californian poppies, poached egg plants or limnanthes, French marigolds, cosmos, fennel and dill. Pot marigolds or calendulas are especially packed with animal magnetism – their bright orange colour attracts predators, such as hoverflies, and draws in bees and other pollinators, which ultimately means better yields.
The female insects feed on calendulas’ protein-rich pollen before laying eggs around colonies of aphids, which provide a ready food source when the larvae hatch.
Planting strongly scented herbs, such as mint, rosemary, oregano and alliums, and especially chives and garlic, in-between crops amazingly act as repellents, confusing insects with strong odours, masking the scent of the intended host plants.
Bane of the garden
Aphids, which are the bane of the garden, can be green, pink, black or grey and attack most plants – indoors and out. They debilitate plants by literally sucking the life out them – drinking the sap, causing flowers to become distorted and new buds to die. While doing this they spread viruses and diseases, which ultimately destroy plants.
You’ll find them on the soft new shoot tips and buds as well as sometimes feeding on roots and leaves. While doing this, they produce a sticky secretion, which on plant foliage becomes a hotbed for sooty mould fungus to grow. Aphids also attract ants, that farm them for their sweet honeydew, and can also become a nuisance on lawns and patio pots.
Wormwood, artemisia absinthium has a particularly strong scent and acts as a deterrent, so plant it liberally to prevent aphids from attacking neighbouring plants, along with thyme, which is a useful companion for roses.
Mint is effective if you have also have a follow-up ant infestation – even in the kitchen you can scatter a few sprigs of mint around the place and watch them disappear!
Create a diversion
This diversion tactic works best on a sheltered site, so the wind doesn’t carry the strong smell away. Some plants like nasturtiums, which are a magnet to pests, can also be used as sacrificial plants to distract pests from attacking your best plants. Use it to lure aphids from your runner and French beans.
The herb summer savory can also be employed to protect broad beans from black bean aphids, and planting broad beans and potatoes together also discourages the pests that attack the other, keeping them healthy as well as improving yields.
Sunflowers will also trap aphids and keep surrounding plants relatively clean without themselves coming to much harm! You might also like to try planting marigolds as a barrier around your salad patch and put a few pots next to your tomatoes – it really does work. Nettles, too, will attract aphids. Slugs have a penchant for chervil, and French marigolds and radish are said to attract root fly from cabbages,
so give these lures a try, as well.
When your trap crop becomes overrun with your pest problem, don’t forget to remove it and dispose of it on the compost heap. As the pest population increases so should their predators, but if you see a decline you may need to buy some in. Surprisingly, you can buy beneficial insects like ladybirds and lacewing larvae online (greengardener.co.uk), which are much more effective than resorting to chemicals.
The scent of marigolds is disliked by most pests and will nurse ailing plants. It also enhances the growth and flavour of most crops grown with it, and the roots produce a chemical which repels nematodes and other pests for up to three years, making it a great companion for root crops. Don’t plant marigolds too close to beans and brassicas, though, as they may hamper their growth.
Companion-planting seems an obvious way forward when it comes to protecting your plants, and things will only improve if you grow a mixture of plants as it makes it far less likely that any pest will settle on
the main crop.
The key to success is observation and, while there are well- known, tried and tested partnerships, recording your own plant combinations and results from year to year will be invaluable in your battle against bugs.
Finally, another natural way to keep your patch pest-free is to make your own remedies. Tomato leaves, for example, have toxic compounds called alkaloids in their leaves. The chopped leaves can be soaked in water overnight and made into a homemade aphid spray. It works by attracting the good bugs, which follow the smell while looking for prey.
Herbal sprays can also be effective against leaf-eating pests. A traditional method is to make a simple ‘tea’ by mashing leaves of catnip, chives, feverfew or marigolds in a couple of cups of boiling water, let them steep until cool before diluting with several more cups of water. Adding a squirt of washing-up liquid to your spray will help them stick to leaves and spread better.
Some old-time gardeners recommend using hot dusts, made from chilli peppers or dill, which are dried and ground up. Sprinkled along seeded rows of onions, cabbage or carrot, in a band at least 15cm in diameter, it’s said to protect plants from ants and reduce the number of onion maggot eggs.
Organic gardeners also swear by garlic. To make a spray to stop aphids in their tracks, mince three or four cloves and mix with 2tsp of liquid paraffin. Let the mixture sit for a couple of days then strain and add to 500ml water. Just 2tsp of this, added to 1 pint of water, will, I’m assured, make a knockout spray!