Citrus Mites - Varieties, Damage Symptoms, Control Strategies

Mites are tiny arachnids that feed on plant sap. They damage leaves, new growth and fruit, impacting tree health and fruit quality. 

Main Varieties of Citrus Mites

The two-spotted spider mite and the citrus red mite are the most prevalent mites found on citrus trees in New Zealand. The two-spotted spider mite (Tetranychus urticae) is small (0.5 mm), spider like and usually green or yellow with two dark spots on its back.

Photo: Two Spotted Spider Mite

 While the citrus red mite (Panonychus citri) is reddish in colour, small, and normally found on the undersides of leaves.

Photo: Citrus Red Mite

Damage Symptoms

• Leaf Discoloration: Mites pierce plant cells with their piercing-sucking mouthparts and extract sap. This can cause leaves to become yellow, stippled, distorted, or stunted.
• Leaf Curling: Severe infestations can cause leaf curling and dropping.
• Webbing: In cases of severe infestation, spider mites may produce fine webbing on the leaves and fruit.
• Reduced photosynthesis: Heavy mite infestations can reduce photosynthesis, leading to weaker plants and lower yields.
• Fruit damage: Mites can cause poor fruit development and blemishes on fruit, making it less appealing. They can also lead to lower yields.

Control Strategies

• Tree Health Maintenance: Keep trees healthy through adequate watering, proper fertilisation, and mulching to minimize stress and susceptibility.
• Prune trees: Remove dead or diseased branches to reduce hiding places for mites.
• Monitor for mites: Regularly check leaves, especially the undersides, for signs of mite activity. Early detection is crucial.
• Encourage natural predators: Planting flowers that attract beneficial insects can help establish a balanced ecosystem. If mite populations are high, consider introducing beneficial insects to control them. Ladybugs, lacewings, and predatory mites (e.g., Phytoseiulus persimilis) are available through Bioforce bioforce.co.nz
• Use organic insecticides: Products based on neem oil or insecticidal soap can be effective against mites. Neem can suffocate mites and is most effective when applied during cooler parts of the day. Make sure you spray the underside of the leaves where most mites live. Always follow the instructions on the label to ensure proper application and safety.