Have you seen ash whitefly infestations?
Be on the lookout for symptoms and report them to Biosecurity Queensland.
Early detection is vital.
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Ash whitefly (Siphoninus phillyreae) is a pest of several horticultural crops and ornamental plants in Europe and north Africa. It has spread to the United States and New Zealand, and been detected in South Australia and New South Wales.
When not under the control of its natural enemies, it can cause significant damage to host plants. Affected plants have unsightly sooty mould which grows on honeydew produced by the pest.
Ash whitefly can be moved on plants from infested areas and can also be moved accidentally in vehicles and on clothes. It could appear in Queensland nurseries and home gardens at any time.
|What does it look like?|
The first sign of an ash whitefly infestation is the small (1-2mm), white, winged adults resting on host plant leaves or fluttering around like tiny moths when disturbed. On an infested plant, the undersides of the leaves carry large numbers of adults and nymphs. The fourth stage nymphs are distinctive with noticeable spines that are tipped with globules of white waxy material.
The whitefly is particularly noticeable on deciduous hosts when they are shedding leaves. The adults swarm around the plant as they prepare to search for an evergreen host.
Ash whitefly breeds on a range of ornamental hosts including ash species, crepe myrtle, privet, magnolia, buckthorn and hawthorn and on fruiting plants including pomegranate, olive, apricot, peach, pear, Japanese plum, apple, citrus and quince. The pest can also infest other small tree and shrub species when populations are high.
Ash whitefly has shown a preference for a temperate climate and temperate species of plants. It could establish easily in the cooler parts of South East Queensland.
|Symptoms and damage|
Heavy infestations lead to premature leaf drop, wilting and smaller fruit. Whitefly infestations produce large quantities of honeydew on which black sooty mould grows. Damage includes loss of fruit and, at times, tree death.
When the pest was first introduced to California in the United States without its natural enemies, it caused a significant amount of unsightly damage to ornamental trees in the urban landscape. Street inventories in 14 cities in California recorded 17% of trees affected.
There are no examples of eradication of ash whitefly in the world.
The pest can be suppressed through the introduction of its natural enemies such as Encarsia inaron. Ash whitefly has been brought completely under control in the USA through the use of this parasite.