What's eating my european hazel 'cosford'?

Hazel 'Cosford' is most seriously damaged by hazel nut weevil, whose larvae hollow out the nuts before harvest. Big bud mite deforms catkins and reduces yield. Aphids colonize shoot tips, and squirrels and wood pigeons take ripe nuts. Good pruning to open the canopy helps reduce pest pressure significantly.

Larvae tunnel through the developing nut, leaving a round exit hole; affected nuts drop early and are inedible. Collect and destroy fallen nuts before mid-August to prevent larvae entering the soil; use a kaolin-clay barrier spray at petal fall on larger plantings.

Buds swell to round, abnormal 'big buds' in winter and fail to open; heavy infestation reduces catkins and nut set. Prune out and burn swollen buds in late winter; no chemical controls are available to gardeners in the UK; replace heavily infested stools.

Pale yellow aphids cluster on shoot undersides, causing leaf curl and sticky honeydew that promotes sooty mould. Blast off with a strong water jet; encourage natural enemies (ladybirds, lacewings); apply insecticidal soap only if infestation is severe.

Nuts taken green, weeks before they ripen, often stripping entire clusters; persistent and hard to deter. Use trunk baffles on trained standards; fine-mesh netting over small bushes from late summer; harvest as soon as husks loosen.