Asian citrus psyllid
Have you seen Asian citrus psyllid?
In Queensland, the Asian citrus psyllid is prohibited matter under the Biosecurity Act 2014.
Be on the lookout for this pest and immediately report them to Biosecurity Queensland. Do not move any plant material off your property as this can spread the pest.
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Like the African citrus psyllid, the Asiancitrus psyllid (Diaphorina citri Kuwayama) is a sap-sucking insect that can transmit the lethal citrus disease, huanglongbing, also known as 'citrus greening'.
While the insect itself is not known to be a major citrus pest, huanglongbing is a serious threat to citrus-producing areas worldwide. The Asian citrus psyllid, African citrus psyllid and huanglongbing are not found in Australia.
In the Americas, high numbers of nymphs distort the growth of leaves and stems and may cause death of new growth. Notching of leaves may also occur. These symptoms are not common in Asia.
The honeydew produced by Asian citrus psyllid can lead to sooty mould growth on plants.
|Distribution||Asian citrus psyllid occurs throughout Asia, and in parts of North, South and Central America, and some islands off Africa. Closer to Australia, it is found in Indonesia (including Papua), East Timor and north-western Papua New Guinea. The psyllid was detected near Darwin in 1915, but was eradicated along with an incursion of citrus canker. There have been no detections of the psyllid in Australia since then.|
Female of D. citri lays eggs on petioles, axillary buds, upper and lower surfaces of young leaves and tender stems. The average incubation period of eggs is 4 days. The eggs then hatch and pass through 5 nymphal instars. First- and second-instar nymphs mostly aggregate and feed inside the folded leaves. Young nymphs are quite docile and move only when disturbed or over-crowded. The nymphs continuously secrete copious amounts of honeydew from the anus and a thread-like waxy substance from the circumanal glands resulting in the growth of black sooty mould on the lower leaves.
The complete life cycle takes 14-48 days, depending on environmental factors such as temperature and season. There is no diapause, but populations are typically low in winter or during dry periods. There are 9-10 generations a year, with up to 16 observed in field cages. Population fluctuations are closely correlated with flushing rhythm of citrus trees, as eggs are laid exclusively on young flush points.
|Crops affected||Orange, grapefruit, mandarin, tangelo, lemon, lime, kumquat, pomelo, trifoliate orange, native citrus|
All citrus cultivars are hosts of the psyllid (e.g. orange, grapefruit, mandarin, tangelo, lemon, lime, kumquat, pomelo, trifoliate orange and native citrus species). Some species and varieties are better hosts than others. Murraya spp. (native and ornamental forms of mock orange/orange jasmine) and Bergera koenigii (curry leaf) are also favoured hosts.
Asian citrus psyllid can also feed on:
|Spread of pest|
Asian citrus psyllid occurs throughout Asia, and in parts of North, South and Central America, and some islands off Africa. Closer to Australia, it is found in Indonesia (including Papua), East Timor and north-western Papua New Guinea. The psyllid was detected near Darwin in 1915, but eradicated during eradication of an incursion of citrus canker. There have been no detections of the psyllid in Australia since then.
Long distance spread most commonly occurs via the movement of plant material infested with the psyllids. Ornamentals and food plants such as mock orange/ orange jasmine (Murraya) and curry leaf (Bergera koenigii), respectively, have been known to spread psyllids. Tropical storms and cyclones may also lead to long distance spread.
Asian citrus psyllid and huanglongbing could be introduced into Australia through the illegal importation of host plants, leaves such as kaffir lime leaves or curry leaves for cooking, or budwood. The Australian Quarantine and Inspection Service (AQIS) closely regulates approved imports of plant material and monitors for illegal plant movement.
|Management and quarantine|
Regularly monitor common host plants, such as citrus, Murraya spp. and curry leaf:
There are simple steps you can take to protect your farm:
|Reference and acknowledgement|
Andrew Beattie (University of Western Sydney), Patricia Barkley (Citrus Australia Limited) and Ceri Pearce (Biosecurity Queensland, Department of Agriculture and Fisheries).