Glassy-winged sharpshooter

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Scientific name

Homalodisca vitripennis

Description

Adults

• 12–14mm long, with a large flat head and prominent eyes.
• When viewed from above, body colour is generally dark brown to black, but is pale to cream-coloured underneath.
• Wings are transparent (hence the 'glassy-winged' name) with reddish veins.
• Females may have a white chalky patch on each wing, and small ivory or yellow dots may be present on their heads.

Nymphs

• Dark grey (first and second stage) to grey (third to fifth stage).
• The cast skin from the final nymphal moult to the adult often adheres to the host plant's stem or leaf surface.

Pupae

• There is no pupal stage.

Eggs

• Individual eggs are 'sausage' shaped and laid in masses that appear as greenish water blisters beneath the leaf.

Plant stage and plant parts affected

Glassy-winged sharpshooters can infest (and affect) plants of any age or growth phase (flowering, fruiting, vegetative), but prefer to feed on fresh, young growth.

They flourish in a wide variety of warm weather habitats, particularly where citrus, avocado, eucalyptus and oleander are growing, as well as in residential, park and riverine (stream-side) locations. Overseas, irrigation of agricultural land, botanical gardens and urban areas has allowed the invasion of this pest into areas that would otherwise be too dry.

Anywhere that host plants can grow, glassy-winged sharpshooters will follow; for example, glassy-winged sharpshooters have been found feeding on native plants at the highest altitudes in French Polynesia.

Plant damage

Key signs of glassy-winged sharpshooter infestation include:

• dehydration of host plant tissues (e.g. wilted foliage, dried out stems)
• less fruit
• poor quality fruit (and juice)
• a whitewashed appearance on lower leaves and branches from excreted liquid*
• the presence of the insects themselves.

* Xylem fluids are not high in sugars or other nutrients, so the excreted liquid of glassy-winged sharpshooter rarely results in sooty mould production.

May be confused with

Glassy-winged sharpshooters look similar to slim cicadas. They could be confused with Australian leafhoppers that are a similar size and colour, with a large head and protruding eyes. An expert is needed to identify glassy-winged sharpshooter under a microscope, so all suspected sightings must be reported.

Distribution

Glassy-winged sharpshooter is native to the Gulf states of the south-eastern United States of America. It is currently known to be present in:

• California, Hawaii, and the southern and south-eastern states of the United States of America
• north-eastern parts of Mexico
• Chile
• the Netherlands
• parts of the Cook Islands
• French Polynesia.

Hosts

Glassy-winged sharpshooter is currently known to infest plants in the following families*: Aceraceae, Agavaceae, Amaranthaceae, Anacardiaceae, Apocynaceae, Aquifoliaceae, Araceae, Araliaceae, Asclepiadaceae, Asteraceae, Begoniaceae, Berberidaceae, Betulaceae, Bignoniaceae, Buxaceae, Caesalpiniaceae, Caprifoliaceae, Caprifoliaceae, Casuarinaceae, Celastraceae, Chenopodiaceae, Clusiaceae, Combretaceae, Convolvulaceae, Cupressaceae, Cycadaceae, Eleagnaceae, Ericeae, Euphorbiaceae, Fabaceae, Ginkoceae, Graminaceae, Hamamelidaceae, Iridaceae, Juglandaceae, Lamiaceae, Lauraceae, Liliaceae, Logaiaceae, Lythraceae, Magnoliaceae, Malvaceae, Meliaceae, Moraceae, Myoporaceae, Myrtaceae, Nyctaginaceae, Nyssaceae, Oleaceae, Onagaaraceae, Phytolaccaceae, Pinaceae, Pittospaceae, Platanaceae, Poaceae, Podocarpaceae, Polypodaceae, Proteaceae, Rosaceae, Rubiaceae, Rutaceae, Salicaceae, Sapindaceae, Sapotaceae, Saxifragaceae, Theaceae, Ulmaceae and Vitaceae (CABI.org).

*Glassy-winged sharpshooter is known to feed on many plant species on which it does not lay eggs.

Glassy-winged sharpshooter infests a wide range of horticultural, ornamental and Australian native plant species. Its known host range is continuing to expand as it spreads into new areas, especially in California and the South Pacific.

As a xylem feeder, it is able to evade host plant defences and, as a result, it appears able to feed on most plant species.

Due to the high volume of fluid intake it requires, glassy-winged sharpshooter can only survive on living host plants.

Life cycle

In southern California, the glassy-winged sharpshooter averages 2 generations per year. In Tahiti, multiple overlapping generations have been reported. Adults live about 2 months.

In California, egg laying begins in early winter and peaks in spring. Small sausage-shaped eggs are laid side-by-side in masses, averaging 10 to 11 eggs. Laid just under the leaf surface, egg masses look like greenish water blisters. Eggs are often covered with a white, chalky material, which is thought to reduce egg parasitism. After the eggs have hatched, the old egg mass blister appears as a tan to brown scar.

Nymphs hatch after 2 weeks and proceed to feed on leaf petioles or small stems, while progressing through 5 moults before becoming winged adults. There is no pupal stage.

A second peak in adult activity occurs in the summer, with the new generation of adults laying eggs mid-summer.

Plants affected

• Multiple hosts

Impacts

Glassy-winged sharpshooter is a highly efficient plant disease-carrying insect. Its economic impact would be significantly increased if the serious bacterial organism Xylella fastidiosa, which causes plant diseases such as Pierce's disease of grapes, citrus variegated chlorosis and phone peach disease, was also present.

Glassy-winged sharpshooter can cause significant damage to plants in its own right, with severe wilting and dehydration leading to reduced crop yields, poor fruit and juice quality and even plant death.

Natural environments may also be affected, as Eucalyptus has been reported to be a host of glassy-winged sharpshooter.

Due to its wide host range, glassy-winged sharpshooter can cause significant damage in urban settings, impacting street trees, backyard fruit crops and other ornamental plants.

An interesting phenomenon known as 'sharpshooter rain' (where excess fluid is excreted by large populations of glassy-winged sharpshooters feeding in trees) is a major public nuisance in Tahiti, and has led to the decline and partial defoliation of ornamental street trees.

The detection of glassy-winged sharpshooter in Queensland could cause restrictions for interstate and international trade.

How it is spread

Most rapid and long-distance movement of glassy-winged sharpshooter is as viable egg masses in nursery plant stock, or in fresh fruit cartons (e.g. citrus or grape).

Adults are strong flyers and can move rapidly from plant to plant. Nymphs are wingless and cannot fly, but can distribute themselves by walking and jumping through the canopy or dropping from plants and walking to new hosts.

The Australian Government closely regulates and approves importation of host plant material that may be infested with glassy-winged sharpshooter, including monitoring for illegal plant movement. This helps to prevent the introduction of exotic pests into Queensland.

Monitoring and action

The best time to check for glassy-winged sharpshooter is when plants are actively growing (usually spring and summer), as this is when insect numbers are likely to be highest.

Check host plants for wilting foliage and dehydrated stems. Look for:

• large leafhopper-like insects sitting on leaves and stems
• patches of watery or white residue that result from the insects feeding (their waste products)
• eggs on the underside of leaves
• nymphs and adults on leaves, stems and branches
• cast skins from the final nymphal moult on stems or leaf surfaces
• evidence of 'sharpshooter rain' underneath trees.

In commercial settings, insect traps (e.g. yellow sticky cards) can be used to monitor for glassy-winged sharpshooter and other exotic pests.

Refer to Plant Health Australia for advice on how to monitor commercial crops for exotic pests, including glassy-winged sharpshooter.

Report suspected glassy-winged sharpshooter immediately using 1 of these methods:

• Report online.
• Phone Biosecurity Queensland on 13 25 23.
• Phone the Exotic Plant Pest Hotline on 1800 084 881.

Prevention

Protect your farm from plant pests and diseases:

• Protect your farm from emergency plant pests
• Understand good farm biosecurity
• Visit the farm biosecurity website

Legal requirements

In Queensland, glassy-winged sharpshooter (Homalodisca vitripennis) is prohibited matter affecting plants under the Biosecurity Act 2014. Suspect glassy-winged sharpshooter must be reported immediately using 1 of these methods:

• Report online.
• Phone Biosecurity Queensland on 13 25 23.
• Phone the Exotic Plant Pest Hotline on 1800 084 881.

By law, everyone has a general biosecurity obligation to take all reasonable and practical steps that are under their control to minimise the risk of introducing and spreading this insect pest.

Further information

• Read the glassy-winged sharpshooter datasheet in the Invasive Species Compendium.
• Find resources on glassy-winged sharpshooter from Plant Health Australia.