Below is a quick guide to pests and diseases that Rhododendrons can be prone to:

Problem:Aphids

Symptoms: Clusters of insects on young growth

Remedy: Spray with Orthene at 2 weekly intervals

Problem: Mites

Symptoms: Leaves yellow (stippled or mottled) and dehydrated in hot dry weather

Remedy: Spray with mite killer

Problem: Thrips

Symptoms:Leaves silver and dry. Brown-black specks appear on underside of leaves

Remedy: Spray with Orthene at 2-3 weekly intervals through summer

Problem: Sooty Mould

Symptoms:Black sooty mould on leaves and twigs

Remedy: Spray with Orthene or Shield

Problem: Petal Blight

Symptoms: Earliest symptom is light brown or whitish coloured circular spots on petals. Spots enlarge to form irregular blotches until whole flower collapses. Petals feel slimy when rubbed between fingers. Diseased flowers dry up and cling to the plant (leaves and stems are not affected)

Remedy:Avoid overhead watering. Pick off diseased flowers. Spray at two weekly intervals with Bravo and Shield

Problem: Lack of Fertiliser

Symptoms: Leaves yellow and/or develop dark purple tone. Slow, stunted growth

Remedy: Fertilise with Butlers Azalea, Camellia and Rhododendron food in late spring after flower finishes and just before new growth starts

Problem: Soil too Alkaline

Symptoms: Decline in vigour and leaves turn yellow while the veins remain green

Remedy: Fertilise with Butlers Azalea, Camellia and Rhododendron Food in late spring after flowering finishes and just before new growth starts. Do NOT lime