What's eating my hazelnut 'winkler'?

Hazelnut 'Winkler' is attacked by nut weevil larvae inside the nuts, big bud mite (Cecidophyopsis ribis relative: Phytoptus avellanae) distorting buds, and aphids on leaves. Squirrels are the dominant nut thief. The nut weevil (Curculio nucum) is the single most damaging pest to nut yield.

Female bores into developing nut to lay eggs; larva eats the kernel, leaving an exit hole and empty shell. Shake adults onto a tarp in early summer and destroy; collect and bin fallen nuts promptly; chickens under the tree help clear fallen infested nuts.

Infested buds swell abnormally and fail to open in spring, reducing shoot and catkin production. Prune and burn affected buds in winter; severely infested stools can be coppiced and regrown; no approved miticide for home use in most regions.

Yellow-green aphids on the underside of leaves cause mottling and heavy honeydew/sooty mold. Encourage natural enemies (ladybirds, parasitic wasps); insecticidal soap spray; avoid excessive nitrogen feeding.

Grey squirrels take unripe nuts weeks before harvest, leaving empty shells under the shrub. Net individual branches with fine mesh just before ripening; harvest nuts as soon as husks begin to yellow; squirrel-proof feeders do not protect nuts.