A Blackfly can weaken and stunt infested plants by sucking their sap. They can also spread virus diseases. ... This is the common blackfly that infests broad beans, runner beans and French beans, as well as spinach, beetroot and spinach beet. They often attack ornamental plants as well.

How do you get rid of blackfly on runner beans?

You can use slug pellets, beer traps or place copper rings around the stems of young plants. If you favour a less aggressive form of slug deterrent you can cover the soil around the plants with crushed oyster or eggshells, gardening grit or sharp gravel.

Does soapy water kill blackfly?

Soapy water as a spray against garden pests. Killing aphids with soapy water is a largely used trick in the book of every hobby gardener. The mixture is also effective against mites, black flies and other pests. ... It is also effective in getting rid of the eggs of different pests.