PESKY PESTS
Aphids, caterpillars, slugs and snails... they’ll all decimate your crops if you let them. But they can be stopped – and you don’t have to use chemicals
DEALING WITH PESTS WITHOUT CHEMICALS
It seems to me that you should treat your crops and garden with the same degree of respect and even reverence as you do your own body and the well-being of your loved ones. So, bearing this in mind, it makes sense to grow all edible crops organically, as part of a holistic garden where you do not use any herbicides, fungicides, pesticides or artificial fertilisers. In fact, I have a basic principle that I do not put anything into the soil or the plants I intend to eat that I would not put onto my plate.
All pests – especially slugs, snails and aphids – will attack weakened plants first. So the best defence against them is healthy plants. Focus your efforts on raising plants that are strong, have not been stressed by lack of water or nutrition, and have not got too hot or too cold in the process.
The healthiest plant is the one best adapted to its particular situation and circumstances – not the biggest or earliest. So make sure your plants are as hardy as possible so they will not be vulnerable to changes in the weather or circumstances that a smaller or later plant easily resists.
Thin seedlings early and widely. It seems harsh to abandon hundreds of healthy young seedlings, but it is essential to leave proper spacing between plants such as carrots, lettuces or radishes that are sown from small seeds so that the remaining seedlings can develop strong, healthy roots. Eat the baby seedlings in salads and learn the lesson that sowing thinly saves a lot of time and money!
CONTROL CATERPILLARS
The main caterpillars that cause damage in a vegetable plot are those of the cabbage white butterfly. There are two kinds of cabbage white – the large and small. The former has caterpillars that are black and yellow (pictured inset right), and the latter’s ones are a pale green and superbly camouflaged against cabbage leaves.
The best defence is a fine netting with a mesh with holes less than 1cm which is put in place immediately after planting out and this will stop the butterflies laying their eggs. But some always get in and I inspect them daily to pick off all the caterpillars I can see.
FED UP WITH APHIDS?
Every garden will have some of these small sap-sucking insects but the best control is to encourage predators such as blue tits, hoverflies and lacewings. Most aphids feed by sucking the sap from plants so look for new, vigorous growth. By growing your plants ‘harder’ – more slowly and therefore stronger – they will be naturally more resistant.
You can also deter them with companion planting – coriander deters them and dill attracts hoverflies and predatory wasps. Sunflowers will also attract aphids away from crops.
BANISH WHITEFLY
Some years – and 2019 was one of them – all brassicas seem to be covered in tiny grey flies that fly into the air when disturbed. Adult whitefly are active throughout the year, and immature nymphs are flat and oval shaped and found
on the undersides of the plant’s leaves.
Infestations can result in sooty mould growing on leaves, which feeds on the sugary excrement of the whitefly and damages leaves.
Light infestations of whitefly are tolerable but if moulds are doing too much harm then use an organic soap spray – made by mixing 1½ teaspoons of a mild liquid soap with 2 pints of water – on the undersides of the leaves.
TACKLE SLUGS AND SNAILS
Slugs and snails perform an invaluable role in the garden by recycling any waste vegetative matter, and they are also an essential part of a compost heap. The problem with them is that they do not discriminate between a fallen leaf and a delicious young seedling. Snails and slugs love to eat young, soft tissue, so the trick is to make it available to them for as short a time as possible.
Resist sowing or planting tender plants too soon. Any plant that is stressed by bad weather, erratic watering or, in particular, overfeeding will be the first to be attacked. Remember that the healthiest plants are those that respond best to the situation they grow in – wherever that might be.
Encourage a wide range of predators to get rid of pests for you. Thrushes, frogs, toads, beetles, centipedes, shrews and hedgehogs all love eating slugs and snails. This needs plenty of cover for the animals, an avoidance of toxic chemicals – such as slug pellets – and a degree of tolerance for collateral damage.