Protect leylandii from Conifer Mite and Cypress Aphid

Love them or hate them, leylandii are now a common sight all over the UK. However increasingly they are being attacked by two insect pests that are turning them brown. Signs of damage are patches or swathes of dead, dying conifer usually starting from lower down and spreading in random patches. Once it is dead, conifer does not regrow so the invisible insect attack should be treated as early as possible.

1. Conifer Mites (Oligonychus ununguis (Jacobi))

Spider mites are hosted by a variety of tree and plantings including spruce, fir, juniper, pine, hemlock and others. Infested trees display mottled foliage which may appear brownish-grey, and needle loss may occur. 
To confirm a mite infection, lightly tap the damaged branches over a white paper and examining the paper for reddish-brown mites which are about the size of pepper grains. In heavy infestations, spider webbing may also be conspicuous.

2. Cypress aphids (Cinara cupressivora)

Damage caused by cypress or conifer aphid develops in late spring and summer. It is found most often at the base of the hedge, but can develop at any height. Large greyish greenfly are sometimes found, but the hedge browning often develops long after the aphids have left the foliage. Clues are left behind, including cast aphid skins and a black fungal growth (sooty mould) that grows on the sugary honeydew excreted by the pest.

How to control conifer mite / cypress aphid

Spraying Oil from Certis is no longer available to us, but both pests can be treated successfully with different insecticide spray products.

Pyrethrum5EC in 100 ml, 250 ml and 1 L bottles. Pyrethins are the active ingredient that is toxic to insects and are derived from the chrysanthemum plant. Pyrethrum is a broad-scale, systemic insecticide that degrades quickly after exposure to UV and high temperatures so it does not leave residues.

Application Rate: 20 ml Pyrethrum in 5 L water

Sirius 1 L
: A physical insecticide that degrades to silica and water after use. Very safe for operators and pets, etc. Works to smother and affect the outer ‘shell’ of the sap-sucking insects. Can be combined in use with Pyrethrum.

Application Rate: 25 ml in 10L water

Bandu 1 L
: Professional  insecticide suitable for a wide range of crops and areas of use. Active ingredient: Deltamethrin. Very low application rate – suitable for re-sprays. Treatment should commence in spring at the first sign of leaf browning and be repeated every 3-6 weeks through summer and autumn.

Application Rate:  Spray foliage until well wetted.  Always read the label.

For more information call freephone 0800 032 6262

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