Pest

By David Marks
French Beans are usually one of the healthier garden vegetables but occasionally they do suffer from problems. Keeping them healthy with regular watering and feeding will go a long way to reducing the effects of any pests or diseases.

The main pest to affect French Beans are slugs, especially in the early stages of growth. Next on the pest list is the aphid which attacks a wide range of vegetables. It’s rarely fatal with French beans but they definitely can reduce the crop considerably.

SLUGS AND FRENCH BEANS

Slugs (and in some cases snails) are attracted to tender young beans just emerging from the ground. They eat out the growing tips which can significantly stunt the plants growth. Read our dedicated pages on slug control which can be found here.

One measure which you can take specifically for French Beans is to protect them when they are very young – in the first three weeks after they appear above ground. This is when they are at their most vulnerable, after this stage the slugs find it difficult to reach the tender growing shoots. Even better is to start the plants off in pots indoors. This will give the slugs only a very small window of opportunity to do much damage.

One method we use for this is to cover the young plants with large squash or water bottles as shown in the picture below. This method not only protects the young plants from slugs and snails but also protects them from harsh winds and the cold.

Large plastic bottle used as a protective cloche preventing slug and snail damage

APHIDS

Aphids (blackfly and greenfly) will almost certainly appear on your plants at some point in each growing season. Worst affected are the tips of new shoots. Our page devoted to aphid control can be found here. Luckily French Beans are normally not affected severely by aphids and manual and organic control is all that is required.

FUNGAL INFECTIONS OF FRENCH BEANS

French Beans sometimes pick up fungal infections especially when the weather is very damp. There is little that can be done to cure the infections and in many cases the beans remain edible even though cropping is reduced.

To reduce the risk of a fungal infection light prune the plants if parts of the foliage / stems touch the ground. Prune away any foliage touching the ground to avoid rain splashing soil onto the foliage.