It’s every gardener's worst nightmare after putting hours of effort into their veggie patches only to have their precious crops devastated by pests. Runner beans are a quintessentially British crop and one of the easiest veggies to grow, they are an allotment staple.

Black bean aphids, or as they are more commonly called, blackflies, are a common pest that can heavily infest broad beans, particularly during spring and summer. They usually appear around this time of year during late spring and early summer. Once they arrive they often multiply into large numbers and are usually found on the shoot tips of broad bean plants.

You must check regularly for blackflies in the summer as they can quickly overwhelm plants.

Backfly like to congregate and stifle the growth of the tiny bean shoots and damage the developing pods nearby. 

A bad blackfly infestation will seriously weaken plants, resulting in a complete stop to the growth of broad beans and the flower buds of ornamental plants such as dahlias, poppies, and nasturtiums.

To help get rid of the pest, gardening experts at Thompson and Morgan suggest pinching out one part of the plant during May to stop the infestation of blackfly.

They said: "Pinch out the growing points of broad beans as soon as beans start to appear at the base of the plant to reduce the risk of blackfly attack."

This gardeners' tip will help remove the backfliess favourite feeding and breeding ground, allowing your crop to focus its energy on growth and pod development.

It is recommended to remove about three inches of the newest growth which is what blackfly prefer to feed on. 

Not only will this gardening hack deter the common pest, but it will also promote bushier growth, leading to more flowers and ultimately, more beans. 

It's ideal to check the beans daily and keep your eyes peeled for clusters of tiny blackflies which will usually be found on the new growth at the top of the plant.