Nature’s own solutions

Pippa Greenwood, from Radio 4’s Gardeners’ Question Time, explains how biocontrols work.

Biocontrols are natural enemies of pests, usually predators or pathogenic nematodes. For example, you can buy ladybirds and their larvae to control aphids.

The precise way these biocontrols work depends on what sort of creature they are – some devour the pest, some lay their eggs in the pest, and others introduce a pathogen into the pest’s body.

There are numerous advantages to biocontrols. They are generally very targeted, so the risk to other creatures is non-existent or very slight. They are harmless to humans, pets, wildlife and plants. There is also no risk of pests building up resistance to them.

Some are supplied mixed with a carrier such as vermiculite, and need to be sprinkled on infested plants. Some come in a container or on a card and just need to be released, while others need to be mixed with water and poured on. Biocontrols are found at larger garden centres or online from a general garden supplier, and often must be used within a few weeks of receipt.