Phytophthora in Toowoomba

Phytophthora is a water mould that can cause dieback in park and street trees. Some species are also a significant threat to biodiversity if spread into natural areas. There are many species of the plant pathogen found in Australia and as yet, Council cannot confirm which species may be present in Queens Park and Toowoomba.

Phytophthora spread

Phytophthora spreads through water moving through or over the soil and by transporting soil or infected plant material by people and animals. The pathogen can also move between trees that have intermingled roots.

Phytophthora has been found in Queens Park, at Picnic Point and in some urban street trees in Toowoomba. Further testing will occur as trees are noticed to be in poor condition.

Effects

Phytophthora can kill susceptible trees. It does this by damaging the roots and vascular system of the tree so that it can not move water and nutrients around as a healthy tree can.

Some trees can recover from a Phytophthora attack. Plant health and good soil condition including good drainage will all help determine if a tree will survive. There are also soil drenching and stem injection interventions that might help. Talking to an arborist would be the best idea if you have a sick tree.

Biosecurity considerations

There is no formal biosecurity obligation for Phytophthora in Queensland. This means the plant pathogen is not reportable and the Queensland Department of Agriculture and Fisheries is not imposing any requirements on people regarding limiting the spread.

National parks

Phytophthora can be extremely damaging to natural ecosystems and is difficult to manage in these locations. If you are a regular visitor to Toowoomba Parks, it is best if you have separate shoes and clothing to visit National Parks either in our area or elsewhere. If this isn’t possible, selecting a shoe type that is very easy to clean and cleaning them before walking in National Parks is recommended. The Australian Government publication Arrive Clean, Leave Clean has recommendations for limiting the spread, including recommendations for cleaning clothing, shoes and equipment.

Cleaning

Cleaning shoes can be achieved with a solution of 70% ethanol or methylated spirits in 30% water. Carry a hard brush and a spray bottle of this solution and use it when leaving the park. First use the hard brush or stick to remove as much mud, soil or organic matter as possible before disinfecting with the solution.

Any surface that comes into contact with and can carry mud, soil or organic matter can spread a plant pathogen. That can include a leaf in your hair, mud on your pants legs, or a water bottle that you rested on the ground. It is important to be aware of these other sources of possible contamination and reduce the likelihood of carrying soil or organic matter away from the site.

Vehicles and equipment can collect and carry soil and organic matter away from the site. Good wash-down protocols should be applied to cleaning mud flaps and tyres and any tools or equipment that is used in contact with the soil. There are no Council provided wash-down facilities in Toowoomba however there are private sector providers.

Management plan

We are working on establishing which species of phytophthora is present in the park and across Toowoomba. Once this is determined, arborists and other experts will be better able to predict what the likely impact on the park will be. A plan of management to assist in conserving the heritage values and significant trees in our parks and streetscapes will be prepared.