How to cultivate your conifers

Conifers offer a colourful, low-maintenance, frost-hardy option in any type of border. However, in recent years, conifers have been under attack by the Italian cypress aphid (Cinara cupressi). Every autumn, you need to protect your conifers against these damaging attacks.

Cypress aphids begin their life cycle in autumn. From April they multiply rapidly, and their numbers peak in June. Warm weather sends them back into hibernation. During winter, blackish-brown sap-sucking aphids feed on the conifer’s twigs and branches. Although the aphids are 2-4 mm long, they are very difficult to see as they are camouflaged by the bark. While feeding on the sap of the foliage a toxic honeydew excretes from their bodies and causes die back of branches and damage to foliage. Damage is only noticed the following season, in summer, which is too late to control. Preventative treatment is of the utmost importance. A useful confirmation of aphid damage is the presence of a black, sooty mould on the stems and/or foliage. Heavy infestations cause the death of entire branches, but the irreversible damage is only evident in summer, which is too late to prevent it.

Aphid-susceptible conifers

Juniperus scopulorum ‘Skyrocket’
Cupressus macrocarpa ‘Gold Crest’
Cupressus sempervirens ‘Stricta’
Cupressocyparis leylandii ‘Castlewellan Gold’

Preventing foliage damage

Take preventative action from late March onwards by applying a systemic insecticide. A number of options are available: Apply a cover spray of Efekto Aphicide (7.5 ml dissolved in 10 litres of water) to small conifers under 2 m in height, using a pressurised garden sprayer.

Preventing damage

With large trees, where it’s impractical to apply a cover spray, drill several holes into the bark at intervals, and pour the mixture into the holes. Efekto Plant Protector or Efekto Aphicide Plus can be used either as a preventive or corrective treatment.
Between April and June, drench around the stem base of each tree. Repeat after approximately 6 weeks. Corrective: Apply as a soil drench around the stem base of each tree when first signs of infestation are noticed. Repeat after approximately 6 weeks.
For both small and large conifers, work Efekto Insecticide Granules Plus (not suitable for edible crops) into the soil, and water well.
For conifers in containers, apply either Efekto Aphicide, Efekto Aphicide Plus, Efekto Plant Protector (not suitable for edible crops) or Efekto Insecticide Granules Plus, as above.