What's eating my hazel 'red filbert'?

Hazel 'Red Filbert' shares the pest profile of all Corylus avellana cultivars. The hazelnut weevil is the worst threat to the crop, boring larvae into developing nuts causing heavy losses. Squirrels harvest the majority of nuts before ripening. Big bud mite, aphids, and hazel sawfly also occur regularly in garden settings.

Larvae tunnel inside developing nuts, leaving them empty or shrivelled; infested nuts fall prematurely. Crop losses can reach 80% in bad years. Shake branches over a sheet in spring to dislodge and destroy adults before egg-laying. Collect and destroy fallen nuts promptly. Kaolin clay or permitted insecticides timed at bud burst can reduce adult feeding.

Strip and take nearly all ripe nuts from the tree, often before the nuts are ready to fall. Net the canopy as nuts approach harvest in autumn. Tree-trunk guards prevent climbing on young trees. Harvest promptly as nuts ripen.

Buds swell abnormally and fail to break, causing blind wood and reduced cropping over time. Prune out and bin swollen buds before mites disperse in spring. No effective miticide is available to home gardeners; severe infestations may warrant removal.

Clusters of pale green aphids on leaf undersides causing honeydew, ant activity, and minor leaf curl. Natural predators (ladybirds, lacewings) usually control populations. Apply insecticidal soap if infestations are heavy and predators are absent.