杏吧原创

AS MOST of the UK recovers from a frigid April and a soggy May, its gardens are starting to perk up. That means so are caterpillars, aphids such as greenflies, and other plant-feeding invertebrates generally seen as the gardener鈥檚 foes.

A common reaction to seeing prized plants covered with bugs is to reach for the pesticide spray. But we should temper that instinct, says , principal entomologist at the UK Royal Horticultural Society. Many invertebrate species in the UK and elsewhere are in decline, and gardens can be a haven 鈥� the UK鈥檚 home gardens collectively add up to an area larger than the country鈥檚 official nature reserves.

You might think there is no shortage of aphids, but they are food for bigger insects, such as ladybirds, lacewings and wasps, not to mention blue tits. While gardens are a much understudied ecological resource, suggests they can support hundreds of invertebrate species, including at least two insects in decline in the UK: two-spot ladybirds and, in the south, stag beetles.

Most synthetic pesticides kill aphids鈥� insect predators too 鈥� and aphids tend to bounce back faster than their predators, requiring repeated spraying. If you must spray, try to use organic, soap-based products, which tend to be less harmful to predators 鈥� though they aren鈥檛 completely non-toxic, says Salisbury. He doesn鈥檛 advise home-made soap solutions as they haven鈥檛 been tested for their effects on plants or wildlife.

There are other ways you can encourage invertebrates into your garden, according to a . These include denser planting (although spiders love bare spots between plants) and choosing British species. The researchers compared how many invertebrates could be supported by three types of typical garden planting scheme: native British plants, 鈥渘ear-native鈥� plants (defined as those from the same genus found in the northern hemisphere) and exotics, or those from the southern hemisphere.

Native plants were the best at supporting ground and foliage-dwelling invertebrates, but the difference wasn鈥檛 that big. For example, 18 exotic plants supported the same number of bugs as 17 near-native and 14 native plants of the same size.

The exception was for , such as honeybees, wild bees and hoverflies. These appreciated the exotic flower beds in late summer and autumn, when they had more blooms. As a result, the team recommends that UK gardeners focus on native plants with some exotics mixed in to extend the flowering season.

But Salisbury鈥檚 main message is that, as far as possible, gardeners should relax about nibbled foliage, aim for a profusion of varied plant species and let the wildlife share their space. 鈥淚t鈥檚 not a garden, it鈥檚 a living ecosystem,鈥� he says.

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