Dr. Phyto

mandarin

Citrus reticulata

Diseases & pests on this plant

• California red scaleAonidiella aurantii

  Tiny reddish-brown scales on leaves, twigs and fruit.

• Queensland fruit flyBactrocera tryoni

  Small 'sting' punctures on ripening fruit, often with a weeping or dimpled spot; maggots (cream-coloured larvae) tunnel the flesh causing internal rot and premature fruit drop. Adults are wasp-like, reddish-brown flies with clear wings seen resting on foliage and fruit.

• citrus leaf minerPhyllocnistis citrella

  Silvery winding tunnels on young leaves, leaf curling.

• citrus root and foot rotPhytophthora citrophthora

  Dark gummy lesions on trunk base, yellowing leaves.

• two-spotted spider miteTetranychus urticae

  Yellow stippling on upper leaf surface, fine webbing.

• citrus greening (Huanglongbing, HLB)Candidatus Liberibacter asiaticusEU-notifiable quarantine organism

  Leaves show a distinctive blotchy, asymmetric yellow mottle that does NOT match on the two sides of the midrib (unlike a nutrient deficiency, which is symmetric); shoots yellow sector by sector; fruit stay small, lopsided and fail to colour properly, staying green at the bottom ("greening") with aborted dark seeds and a bitter taste; the tree slowly declines and dies. Spread by the citrus psyllid Diaphorina citri.

• Citrus gall waspBruchophagus fellis

  Woody, elongated swellings (galls) on green twigs and stems, becoming corky and often several centimetres long; heavily galled branches are weak, dieback and reduced fruiting follow. Tiny exit holes appear on galls after adult wasps emerge in spring.

• Asian citrus psyllid (HLB vector)Diaphorina citriEU-notifiable quarantine organism

  Tiny (3–4 mm) brown-mottled psyllids that sit at a characteristic 30–45° head-down angle on new citrus shoots; nymphs produce curly white waxy tubules and honeydew on the flush; heavy feeding twists and stunts new leaves. Their importance is as the vector of citrus greening (HLB) rather than the direct feeding damage.

• citrus black spotPhyllosticta citricarpaEU-notifiable quarantine organism

  Small, sunken, dark spots with a grey centre and a raised dark margin develop on the rind of the fruit (the classic "hard spot"), sometimes with tiny black dots (pycnidia) in the centre; freckle-like and cracked-spot forms also occur; heavy infection causes premature fruit drop. Leaves are usually symptomless. Spots often appear late, after fruit reach the market.

• greasy spotMycosphaerella citri

  Greasy-looking yellow-brown blisters on leaf underside.

• oriental fruit flyBactrocera dorsalisEU-notifiable quarantine organism

  The female stings ripening fruit (citrus, peach, many hosts) and lays eggs under the skin; maggots tunnel the flesh, which softens, browns and rots from the inside while the outside may look only slightly blemished with small puncture marks; infested fruit drop early. The adult is a wasp-like fly with a mostly dark abdomen and clear wings.

• Mal seccoPlenodomus tracheiphilus

  Yellowing of veins on individual shoots, salmon-pink/orange wood discoloration in cross-section of dying branches, leaves drop with petiole remaining, progressive whole-canopy dieback.

• citrus blackflyAleurocanthus woglumiEU-notifiable quarantine organism

  Black slipper-shaped scales (the nymphal stage — very distinctive) on undersides of citrus leaves, copious honeydew + black sooty mould on leaves + fruit + ground beneath trees, leaf yellowing + premature drop, branch dieback in heavy infestations, fruit downgrade from cosmetic damage.

• citrus cankerXanthomonas citri subsp. citriEU-notifiable quarantine organism

  Raised corky lesions on leaves with a yellow halo, dark spots on twigs and fruit with water-soaked margins, early fruit drop, severe defoliation in heavily infected trees.