The current major troublesome type of aphid is the Cypress Aphid which predominantly affects conifer hedging. The damage inflicted on conifer hedges by the cypress aphid Cinara cupressi is profound and can lead to large brown patches on the hedge which leads to localised death and reduces the aesthetic look of the hedge. The aphid is active from May to October and it is important to catch this problem early and apply treatments to stop the spread. Cypress Aphid causes damage to Western Red Cedar, Lawsons Cypress, Leylandii and Monterey Cypress.
Some species, such as woolly aphid on apple and beech, cover themselves with a fluffy white waxy secretion. Most aphids feed on the foliage, stems and flowers but some suck sap from the roots. For much of the year, aphid colonies consist of wingless females that give birth to live young. Winged forms develop when overcrowding or a deterioration in the host plant induces a need to move to another plant. The egg-laying form of aphids only develops at the end of the aphids period of activity, usually autumn, but for some species this can be in the summer. Most aphid species overwinter as eggs but some can remain as active aphids, particularly in mild winters or on indoor plants.
Control of aphids on woody and non woody plants is very easy and is usually done by adopting good cultural techniques and by reducing exploding populations by timely treatments. The Cultural techniques that can be employed is ensuring that overwintering aphids do not have weeds to survive on during the winter. Biologically it is important to have a garden that is diverse in plant material to attract beneficial insects such as ladybirds that could control the aphid population. In terms of treatments the old horticultural practice of applying a horticultural winter oil wash to kill over wintering eggs and young insects is still a very sound practice. Many aphid control products now exist for applying systemically to woody plants and these are very effective.