What's eating my korean rhododendron?

Korean rhododendron is deciduous, so lace bug damage is less concealed than on evergreen species, but the pest still occurs where plants are sun-exposed. Aphids target new growth in spring before leaves harden. Vine weevil and leafhoppers round out the main threats. Hardy and vigorous, it generally recovers well from moderate attack.

Yellow stippling on upper leaf surfaces with dark excrement specks on undersides. Deciduous leaves mean damage is more visible mid-season; worst on plants in full sun. Spray undersides of leaves with insecticidal soap or pyrethroid in late spring. Repeat if populations rebuild in midsummer. Move susceptible plants to partial shade if attacks are recurrent.

Colonies on new shoot tips and undersides of young leaves cause curling, sticky honeydew, and sooty mould. Emergence in early spring when buds break is the peak risk period. Dislodge light infestations with a strong jet of water. Spray with insecticidal soap or neem oil. Encourage natural predators such as ladybirds and lacewings by avoiding broad-spectrum insecticides.

Nocturnal adult feeding causes notched leaf edges; larvae attack roots, especially in containerised plants, leading to wilting. Hand-pick adults at night. Apply beneficial nematode drench to moist soil in late summer. Use a registered vine weevil insecticide for pot-grown plants if grubs are found.