A pest can be defined as an animal that is detrimental to humans or human concerns. In the vegetable garden, the most common ones are slugs and snails, aphids (blackfly and greenfly being the most prolific) and the caterpillars of large white and small white butterflies (often collectively called cabbage white butterflies). In the spring, in some areas, wood pigeons can also be a nuisance – eating young brassica plants in particular. Fruits can also be devoured by a number of different birds and some rodents.
The good news for vegans is that there is no need to kill any of these animals. We will look at barriers to keep pests away from your crops, and relocation (removing pests from your plot), but first, and by far the most important, is to create high biodiversity so that the pests are kept in check naturally.
The problem with chemical pesticides is that they kill the beneficial predators as well as the pests (upon which they prey). Classic examples include the larvae of ladybirds, hoverflies and lacewings, which devour aphids, yet are equally as susceptible to most pesticides as the aphids themselves. Without these predators in our landscape, pests like aphids, which breed very rapidly, can quickly get a hold and damage crops. With a healthy ecosystem there will always be a balance, however with predators keeping their prey under control.
It helps to start off with the notion that you will always share some of your crops with other animals, and that there’s nothing wrong with that. Plant a few more than you need for yourself, knowing that some sharing will go on over the season. Enjoy the fact that your plot is an ecosystem and not just a production house and that you are playing a part in creating that.
So the most effective, environmentally-friendly and least time-consuming method of pest control is simply to ensure your plot is as wildlife-rich as possible. Here are some examples of the types of predators you want to attract:
- Bats: eat flying insects and some caterpillars – attract them with bat boxes and flowering plants that night-flying insects visit, such as evening primrose, jasmine and honeysuckle.
- Beetles and centipedes: beetles eat slugs’ eggs, and centipedes eat slugs and snails – attract both with moist shady areas such as compost heaps and mulches.
- Birds: small birds eat aphids and other pests – attract them with trees, shrubs, hedges and bird boxes.
Frogs and toads: eat flies and aphids – attract them with ponds and damp logs or stone piles for hibernation.
Hedgehogs: eat slugs, millipedes, caterpillars – attract them with low shrubs, log piles and gaps under fences so they can come and go.
Ladybirds, hoverflies and lacewings: as mentioned, the larvae of all these eat aphids, as do adult ladybirds – attract them with insect hotels (hollow stems or straw packed in open-ended containers), and attract adult hoverflies with flowering plants.
- Newts: eat slugs, snails and insects – attract them in the same way as for frogs and toads.
- Slow worms: legless lizards (not snakes) eat slugs – attract them with areas of long grass, stone piles and compost heaps.
It’s easy and fun (for children too) to create gardens that attract wildlife. You’ll see from the above list a clear number of additions to your garden, which will not only encourage beneficial animals, but also make your garden more attractive and interesting. Priorities would be:
- Pond(s) with easy access for small animals and shallow areas, marginal plants but no fish (which eat the eggs and young of amphibians and insects)
- A wild patch with long grasses and nettles
- A wildflower area
- Piles of logs, stones, leaves, hedge trimmings etc.
- Insect hotels, bird boxes and bat boxes.
Even small gardens can cater for many of these – they don’t have to take up much room.
Another effective technique is to leave a small number of some crops to stay in the ground to continue to grow (and maybe flower) after harvesting their neighbours. An example would be to leave one or two sprouting broccoli plants to fully flower, rather than pulling them all up once harvesting is finished in late spring. These will retain the population of beneficial predators visiting your patch, rather than moving on once their food source or homes have gone.
In some cases you may need to create barriers to prevent other animals getting to your crops. Examples are:
- Fencing to keep rabbits off the allotment
- Fruit cages to keep birds off soft fruits like berries and currants
- Netting over cane or pipe structures to keep pigeons and butterflies off brassicas
- Horticultural fleece or mesh to prevent small pests like flea beetles or carrot root fly (as well as butterflies and larger pests)
- Barriers to deter snails and slugs such as soot, ash, human hair, or copper strips around raised beds and pots
- Cloches to protect crops – plastic bottles cut in half and placed over individual young brassicas or squashes, for example.
Occasionally you may find you need to supplement your other protection methods by relocating a few repeat offenders! This is especially relevant for slugs and snails. In this case, relocating means gathering them up in a bucket or lidded container and taking them at least 100 metres away; snails are homing creatures so lobbing them over the garden fence certainly won’t work!
The best time to collect molluscs is at dusk, after rain and during the spring. Ideally wear a head torch, hold the container in one hand and gently pick the snails off with the other as you move around your plot. You will find a large pair of tweezers or an old spoon will help with the slugs as their slime is particularly slippery (and difficult to wash off your fingers afterwards). You may be surprised at the large number you collect at first, but after a few days the numbers will decrease. Relocate them somewhere like a park, woodland edge or hedgerow, away from other people’s gardens. You may find this nightly activity surprisingly addictive, and it’s a great opportunity to experience other nightlife on your plot, such as bats, foxes and owls.
Another method is to collect them during the day by finding out where they hide away. Common places are under pots/tubs, around the rims of plant pots and under pieces of wood.
Pest control can also be enhanced by using companion planting: using specific plants amongst your crops for their benefit. Examples include:
- Sacrificial plants such as nasturtiums that are susceptible to blackfly attack. These will in turn attract the ladybirds, hoverflies and other predators which will control the aphids on your crops as well. They will also attract white butterflies away from your brassicas.
- Flowering plants that attract beneficial insects like hoverflies and other pollinators, such as lavender, thyme and poached egg plants.
- Mint which deters flea beetles.
- Onions and other alliums growing amongst carrots will deter carrot root fly.
- Strong smelling herbs like mint, chives, basil and thyme can deter aphids.
- French marigolds can deter whitefly.