2019 Citrus Tech Forum: Biosecurity begins with best practice
21 January 2019
A commitment to best practice at Wayne Parr’s Queensland nursery not only ensures quality citrus trees for his customers, but also provides an important role in biosecurity of the industry. Wayne and his wife Sue operate Golden Grove Nursery at Torbanlea, just west of Hervey Bay, and supply about 240,000 nursery trees annually. It has sold trees to Queensland citrus growers since 1987. The family operation, which now involves Wayne’s Wife, son and daughter, is fastidious and continues to maintain best practice. Golden Grove is one of the largest fruit tree production nurseries in Australia and one of only a few fruit tree nurseries accredited with the Nursery Industry Accreditation Scheme of Australia (NIASA). NIASA is a national scheme for production nurseries and potting mix businesses which operate in accordance with a set of national ‘best practice’ guidelines. The NIASA Best Practice Guidelines have been developed over a period of years and spell out technical and management requirements. The guidelines are regularly reviewed, ensuring they cover relevant and current production and environmental issues. Participants are audited each year to ensure they comply. Mr Parr said 154 Australian production nurseries and potting mix companies are currently signed up to the NIASA scheme. He is also a member of the International Society of Citrus Nurserymen, whose members visit each other and network regularly to see firsthand the latest citrus nursery technology and techniques. “We can keep the industry safe by applying Best Practice and using clean citrus propagation material,” Mr Parr said. Best Practice and clean propagation material also ensures growers receive quality trees with the best chance to maximise productivity. At his nursery, rootstock seedlings are germinated in seedling trays and picked out into growing tubes when the seedling is quite small. During this process each seedling is inspected for trueness to type and checked for a strong straight tap root system. Through this procedure up to 40% of seedlings may be culled to achieve a high-quality standard of seedlings to start off a high-quality citrus nursery tree. The seedlings are inspected at each stage of potting on to ensure the tap root system is straight and there are no kinks in the emerging roots. Seedlings with twisted roots can cause premature death in older trees. Soil can be a conduit to disease so all growing media is tested for pathogens, while all budwood is Auscitrus-approved. Virus and Viriod Diseases can be transferred through sap, so all secateurs and knives are cleaned between varieties. Mr Parr said the biggest component of a nursery is labour, which accounts for over 60% of production costs. “If you don’t invest in quality components, clean propagation material, best practices and skilled labour into the citrus nursery trees, you cannot produce a high-quality citrus nursery tree.” The citrus industry believes implementing a traceability system is an important step in preventing disease from entering the industry, with Auscitrus developing an Australian certification scheme. A pilot program called the Citrus Secure scheme has been implemented, with a few nurseries involved. Any nursery can sign up to the scheme. Once they’re in they have the right to use the Citrus Secure trademark. Nurseries in the program agree to be audited yearly, which will provide assurance that only tested budwood and rootstock are being used. The goal is that growers recognise the Citrus Secure trademark, and that will impact their choice in who to purchase nursery trees from. Currently in Australia, the use of tested budwood and rootstock is voluntary. While most of the better nurseries use tested material, the continued use of untested material by a minority creates risks for the industry. Untested budwood or rootstock increases the industry’s exposure to biosecurity threats including citrus canker and huanglongbing disease (HLB). Mr Parr said the cost of protecting the industry would be insignificant to the cost of a major disease like HLB entering the industry.