Biological Pest Control: Nematodes As A Chemical-Free Option

Different nematode species target different problems. Some are used against slugs, others against vine weevil grubs feeding on plant roots in containers and borders, and others against chafer grubs or leatherjackets damaging lawns. Because they are pest-specific, the right choice depends on identifying which pest is actually causing the damage.

Bees and other pollinating insects rely on gardens for a large share of their food, especially in built-up areas where wildflower meadows are scarce. A garden that offers flowers from early spring right through to autumn does far more for pollinators than one with a single showy burst of colour in June.

Nematodes are microscopic roundworms that occur naturally in soil, and certain species have been developed for use against specific garden pests. Rather than acting as a broad chemical treatment, each nematode species is matched to a particular pest, seeking it out and interrupting its lifecycle with far less impact on the rest of the garden than a chemical spray.

Fish are worth thinking through carefully. Ornamental fish will happily eat frogspawn and tadpoles, so a pond intended mainly for amphibians is usually better left fish-free. Leaving some leaf litter to settle at the bottom over autumn also gives amphibians a place to shelter through the colder months.

Design details matter more than they might appear to. Good insect houses combine hollow stems, such as bamboo or reed, with drilled wood blocks offering a range of hole diameters, roughly 2 to 10mm, since different species use different sized cavities. Natural, untreated materials are preferable to anything varnished or chemically treated.

Wildlife value in a garden comes as much from layout as from individual plant choices. A layered structure, trees or large shrubs at the back, mid-height planting beneath, and ground cover or climbers filling the gaps, mimics the natural habitat edges that many species evolved to use, giving insects, www.gardenwildlife.com birds and small mammals shelter at every level.