nature in balance It is possible to keep garden pests under control while giving a priority to wildlife in your garden
Controlling pests in a wildlife garden remains a worry for lots of gardeners. How do you keep those one or two voracious nuisances at bay without wiping out the whole gang of their relatives that you’re keen to encourage? It’s not an easy balance to strike, but with a bit of thought, principally about prevention, the good news is it can be done without resorting to pesticides. Preventing pests becoming a problem in the first place? When it comes to pests, that old proverb about an ounce of prevention is so true! Stopping pests getting a hold in the first place is doubly so for the wildlife gardener. The most straightforward way of doing this involves preventing them from getting to their intended targets – but that’s obviously a good deal easier said than done. Some kinds of plants can be protected physically – grown under cloches for instance – while some pests, such as slugs can be kept away by sharp gravel or copper rings around the base of the plant. These kinds of methods aren’t appropriate for everything, but where they are, they can be very effective. Natural, non-pesticide repellents can also sometimes be helpful. Cedar-wood chips and citronella oil, for example, can be used to keep insects away from particular areas and many people have found them especially effective at warding off mosquitoes and other biting insects that can be such a plague on summer evenings. Mint is another old country remedy that some gardeners swear by – grow it in your garden, or pack around any bulbs or seeds that you’re storing.
What plants will keep pests away? Generations of gardeners have grown pyrethrum to benefit from the natural insecticide it gives off, using it to protect vulnerable plants. It has a place in the wildlife garden, but it’s important to remember that although it’s ‘natural’ it’s still pretty potent and will deter all kinds of insects, not just the pest species, so where you plant it needs to be thought out carefully. Other plants known to be useful in keeping pests away are more selective. Sage, thyme and rosemary, for instance, will combat caterpillars, wormwood and rue keep down ticks, while aphids seem not to like members of the onion family.
What insects are good for pest control? The number one insect ‘good-guy’ is the ladybird – each one happily munching through a huge number of aphids over its 38
lifetime. The slightly less well known lacewing, at least as a larva, is another champion aphid-eater, as well as having a voracious appetite for a range of small caterpillars and insect eggs in general. The contribution of many other kinds of helpful bugs often goes largely unrecognised. Wasps and hornets – although seen as nuisances in their own right – consume large numbers of caterpillars and insect pests, while the fearsomelooking Devil’s Coachman has a real taste for slugs. Many common ground beetles share the Coachman’s love of slugs, adding weevils, leatherjackets and chafer grubs to the menu, and any hover flies you see in your garden will be doing their bit to keep aphids from getting out of hand.
Controlling slugs without slug pellets? Gardeners need no reminder of the ravages that slugs can reek on young, tender plants, but for the wildlife gardener the slug pellet remedy is a non-starter. Fortunately there are other options. Sharp sand and copper rings can help, while wool shoddy – a by-product of the textile industry - makes a great natural slug deterrent. The added bonus of this approach is that shoddy is also a slow release nitrogen fertiliser. Although you once needed a friendly sheep farmer or a local woollen mill to get the stuff, these days it is conveniently packaged and purpose-marketed for the job. The state-of-the-art in pesticide-free slug control, however, involves biological control, using a pre-packaged nematode worm. You simply make up the solution in your watering can and then water these microscopic creatures into the soil – the nematodes will do the rest. Highly specific, they only target slugs, passing on a lethal disease that doesn’t infect any other kinds of creatures and allowing your hostas to thrive without having huge chunks chewed out of them! Pest control presents a few challenges for the wildlife gardener, but it is possible to meet the needs of the wild creatures you’re pleased to see, without having to put up with too much damage from those that aren’t so welcome. It’s always going to be impossible to be entirely pest-free, so you’re bound to see the odd chewed stalk, but don’t forget that any unwanted bugs you do have will probably make the perfect meal for something you will be happy to have visit. Nature is nothing if not balanced!
The April 2018 issue of Devon Country Gardener Magazine