APHIDS - GREENFLY / BLACKFLY "I had a bad aphid problem on angel pelargoniums but soft soap and aphidoletes made them completely clean. In fact I then won 2 cups at the horticultural show!" Mrs R. from Scotland. Aphids are one of the most troublesome pests both underglass and outdoors, attacking a wide range of plants. Natural controls are available to control aphids both under glass and outdoors, details of both are available at the end of the page. All Aphids are similar in appearance although they vary greatly in colour but are most commonly green and black. They are small with long spindly legs and antennae. During the summer they can appear in wingless form as they feed on the plant, but as the population increases winged forms appear which help to spread the infection. Aphids feed by sucking the sap from the plant, this stunts the growth and causes distortion of the growing point. The aphid absorbs large quantities of plant sap in order to obtain enough protein. This sap contains excess sugar that the aphid excretes as honeydew. This honeydew is sticky and coats the lower leaves, after a while mould will develop which is unsightly and reduces the plants ability to manufacture food causing further loss of vigor. Aphids also carry virus diseases which may do long term harm, reducing the plant vigor. Left: A heavy infestation of Aphids.. Aphids are fast breeders - each female is capable of producing 6-8 live young daily over a 2/3 week period. Importing just one aphid on a plant can quickly lead to severe infestation. It is essential to check all plants brought into the greenhouse or conservatory for signs of infestation and deal immediately with any aphids present. In summer winged females will come in through greenhouse vents, so during warm weather be extra vigilant.