What's eating my english walnut 'lara'?

English Walnut 'Lara' (a French cultivar widely grown in Europe) faces walnut aphid, walnut blister mite, codling moth, and walnut husk fly. In European conditions, walnut aphid and the walnut leaf blister mite (Aceria erinea) are the most commonly encountered pests, causing distinctive felt-like galls on leaves.

Pale yellow colonies under leaflets from late spring through summer; honeydew drops on fruit and foliage; heavy pressure reduces nut weight Encourage natural predators; spray with insecticidal soap or neem oil on young trees; established trees in good health often suppress populations naturally

Yellowish-green blisters on upper leaf surface with creamy-white felt-like patches of mite colonies on the underside; cosmetic damage, rarely affects yield Damage is mostly cosmetic; remove and destroy affected leaves; lime sulphur or sulphur spray applied at bud burst reduces overwintering populations

Caterpillars bore into developing nuts, leaving frass trails; causes premature drop and inedible kernels Pheromone traps to guide timing; codling moth granulosis virus spray at egg hatch; collect and destroy dropped nuts promptly

Maggots turn the green husk black and rotten; shell staining and reduced kernel quality follow Yellow sticky traps; spinosad or kaolin clay spray from late summer when flies are first trapped