CITRUS INDUSTRY

The Hon. R.P. WORTLEY (14:58): I seek leave to ask the Minister for Agriculture, Food and Fisheries a question about biosecurity.

Leave granted.

The Hon. R.P. WORTLEY: The government has set out as one of its priorities premium food from our clean and green environment. Will the minister advise the council of a research project which helps to maintain this environment?

The Hon. G.E. GAGO (Minister for Agriculture, Food and Fisheries, Minister for Forests, Minister for Regional Development, Minister for the Status of Women, Minister for State/Local Government Relations) (14:58): I thank the honourable member for his most important question. The member is correct in identifying the pride with which South Australia regards its clean and green surrounds and the premium quality food that we produce.

While Biosecurity SA (which is part of PIRSA) works tirelessly to help ensure that we maintain our great reputation as a source of food from our natural environment by keeping bugs and pests out, SARDI also has an important role through the ongoing research about areas where we can improve. I understand that Kelly's citrus thrips are a key pest of navel and valencia oranges, lemons and grapefruits.

Members interjecting:

The Hon. G.E. GAGO: They can laugh, Mr President, but this thrip is a very important little insect. These thrips feed on developing—

Members interjecting:

The Hon. G.E. GAGO: They don't care about our citrus industry. Thrips are very important to our citrus industry and you can see that the opposition don't care; they are laughing about this—they think it's a joke. Shame on them. These thrips feed on developing fruit causing damage to the fruit and reducing the pack-out of export quality fruit and, in fact, making some fruit unsaleable.

Traditional control programs of this pest have, up until now, relied heavily on the application of insecticides and, of course, it is an ongoing interest of producers to find ways to minimise insecticides used in production, not only to reduce costs but also to reduce environmental impact.

SARDI has been undertaking work on a natural and low chemical input solution to the problem posed by this citrus pest. Soil-dwelling predatory mites have been identified as a potential biological control for thrips which pupate in the soil. Previous research findings have shown that, where the populations of these mites are high, the emergence of thrips from the soil is reduced by more than 50 per cent.

Building on data such as this gathered from earlier projects, SARDI has used compost to boost the number of mites which feed on thrips. So using composting as a method commonplace in many household gardens, SARDI worked on how to increase mite densities. Investigations included a range of composting materials, including recycled green waste, grape mark and animal manure.

Composting uses materials, in particular, those which break down and add to the soil. There is a range of beneficial uses including conditioning and fertilising the soil by adding humus, nutrients and beneficial soil bacteria. In domestic settings, it is also used to help retain soil moisture, control temperature and help suppress weed growth and may also help prevent erosion.

The findings were positive, I understand, providing confirmation that compost, as well as providing benefits to crop production, reduced the need for water and building up soil. The application of composting soil amendments provided an effective integrated pest management system for thrip control in Australian citrus and also provides a range of significant crop production, environmental and ecosystem service benefits.

I am advised that the trials showed increases in both yield and size of fruit, which means a more valuable fruit in the market, and composting provides a use for recycled urban green waste which is collected by composting companies, also helping to delay the release of organic carbon into the atmosphere. So there is a knock-on benefit to the ecosystem.

The trial's results will be communicated through industry forums and journals over the coming months. This is very good news for the industry as it has potential for water and nutrient savings and the use of products that are less disruptive to beneficial mites and insects where application of insecticides is necessary.

The improvement in production systems using research such as this helps our primary production sector build on its enviable reputation and is another example why the government wants to direct efforts to premium food and wine from our clean environment because it pays dividends for primary producers in this state. This work has been carried out over six years by SARDI scientists with the support of Horticulture Australia Ltd and compost suppliers such as Jeffries. As I said, this is very good news for our citrus industry.