Blackfly & Greenfly. Very common on all types of plants. Colonies are visible around new buds or shoots in particular. Leaves may twist or yellow. Sticky honeydew can cause subsequent growth of black Sooty Mould. Product solution: Provado Ultimate Bug Killer ready to use/concentrate/aerosol, Organic Bug Free, Provado Ultimate Fruit and Vegetable Bug Killer ready to use/concentrate, Sprayday Greenfly Killer, Greenhouse Fly Catchers.