Portrait of a red imported fire ant, Solenopsis invicta.
Portrait of a red imported fire ant, Solenopsis invicta. Alex Wild - University of Texas

Four pests as scary as the Yellow Crazy Ant

A YELLOW crazy ant nest was recently found in Lismore, but how do those crazy critters measure up against other pests which have invaded the region?

An exotic plant pest (EPP), like the yellow crazy ant, is a disease causing organism or an invertebrate not present in Australia and which threatens agricultural production, forestry or native and amenity plants.

EPPs and diseases threaten New South Wales agriculture, horticulture, environment and economy.

These are some of the EPPs on the DPI's list for the North Coast:

  • Red imported fire ant Solenopsis invicta
The red imported fire ants pose a huge biosecurity threat.

Photo Contributed
The red imported fire ants pose a huge biosecurity threat. Photo Contributed Contributed

The red imported fire ant has the capacity to form 'super colonies' with multiple queens which can provide the ability to spread rapidly and develop extensive colonies. Red imported fire ants are opportunistic feeders that are omnivorous and prey on invertebrates, vertebrates, and plants.

They destroy seeds, harvest honeydew from specialised invertebrates and also scavenge. This can affect the whole ecosystem through reducing plant populations and competing with native herbivores and insects for food.

They are omnivores, preying on invertebrates and vertebrates and eating plants and honeydew. They are highly aggressive, with a venomous sting used to kill their prey and defend their nest. They swarm in large numbers to attack any animal disturbing their nest. They are tiny (2-6 mm) but their sting and high numbers enable them to overwhelm and kill prey much larger than they are.

  • Spotted-winged drosophila (Drosophila suzukii)

 

Spotted wing drosophila (SWD) is a small fly similar in size to vinegar flies which sometimes gather around over-ripe fruit.
Spotted wing drosophila (SWD) is a small fly similar in size to vinegar flies which sometimes gather around over-ripe fruit. DPI

Spotted wing drosophila (SWD) is a small fly similar in size to vinegar flies which sometimes gather around over-ripe fruit.

Most drosophila flies feed on damaged over-ripe fruit. Spotted wing drosophila is a serious pest because it attacks healthy ripening fruit as well as damaged or split fruit.

Female SWD prefer to lay eggs in ripe fruit but will also lay eggs in unripe, overripe and damaged fruit.

Eggs are laid just under the skin of the fruit creating a small puncture or 'sting' on the fruit surface.

Affected fruit does not show obvious symptoms of infestation until the flesh starts to break down leading to discolouration. White larvae are noticeable in the rotting flesh.

Hosts: stonefruit, apples, grapes, berries.

  • Glassy-winged sharpshooter (Homalodisca vitripennis)
Glassy-winged sharpshooter (GWSS) (Homalodisca vitripennis) is an exotic plant pest. This insect is a serious threat to Australia's grape, citrus and stonefruit industries.
Glassy-winged sharpshooter (GWSS) (Homalodisca vitripennis) is an exotic plant pest. This insect is a serious threat to Australia's grape, citrus and stonefruit industries. DPI

Glassy-winged sharpshooter (GWSS) (Homalodisca vitripennis) is an exotic plant pest. This insect is a serious threat to Australia's grape, citrus and stonefruit industries.

GWSS feed on woody plant tissues such as stems, trunks, branches and leaf petioles. Needle-like mouthparts are inserted into the plant's internal water transport system. During feeding droplets of clear liquid are excreted. When these droplets dry a residue remains which gives the plant a whitewashed appearance.

Plants infected by Xylella fastidiosa become reservoirs of the bacterium which GWSS can pick up and transmit to other host plants.

Once GWSS has fed on a plant infected with Xylella fastidiosa the insect can carry the bacterium to another plant and transmit the disease while feeding.

Hosts: grapevines, citrus, cherries, stonefruit, almonds.

  • Tomato-potato psyllid (Bactericera cockerelli)
The tomato potato psyllid (TPP) is a tiny sap-sucking insect is a serious concern to Australian horticluture
The tomato potato psyllid (TPP) is a tiny sap-sucking insect is a serious concern to Australian horticluture Contributed

TPP can cause 'psyllid yellows', which can result in: yellowing leaves, an upright appearance of leaves in severe cases, early death of the plant.

It can also result in poor productivity of crops due to the introduction of phytotoxins during feeding, and reduce the quality of produce resulting in misshapen and small fruits or tubers.

TPP can also carry the bacterial pathogen Candidatus Liberibacter solanacearum, which causes the disease 'zebra chip' in potatoes. Symptoms of zebra chip include leaf rolling, purpling and discolouration of tubers.

Hosts: potatoes, tomatoes, capsicums, chillies

Reporting pests

Although Biosecurity NSW staff are always looking out for exotic plant pests and diseases, you can help by reporting any unusual symptoms or pest.

You can call the EPP Hotline 1800 084 881 and email clear photos with a brief description of the situation and your contact details to biosecurity@dpi.nsw.gov.au