At the present time, the number one biological security threat to Australian agriculture is a bacteria most will never have heard of: Xylella fastidiosa (Xf). This so far incurable bacterial disease causes plants to wither and possibly die (dieback), scorching and browning leaves and reducing the size of fruit in a wide variety of important crops including olive, almond, avocado, coffee, grapevine, citrus and many herbaceous and forest species. It could also infect native Australian and ornamental plants.
Overseas, Xf is arguably the greatest disease threat to food security and agricultural productivity worldwide. In Apulia, Italy, Xf has left devastating scenes of dead and dying olive trees in its wake and it could cost $US22 billion to control the outbreak there over the next 50 years. If it spreads through Europe the losses in just the olive industry alone are projected to reach up to €5.2 billion per year. Already widely distributed in the Americas, it has been identified in Spain, France, Israel, Iran and Taiwan, raising international alarms about the potential for a global Xf epidemic.
The key to containing Xf is early detection, which isn’t easy given that some infections don’t cause visual symptoms until 8-10 months. And during this period, the asymptomatic plants continue to be infectious. However, the new research takes us a step closer to developing a rapid and more accurate large-scale screening process of at-risk crop species by enhancing the effectiveness of airborne scanning that uses hyperspectral imaging. Global warming and international trade are causing unprecedented risks to agriculture, particularly with emerging and re-emerging pathogens that cause yield losses exceeding 30 per cent in food-deficit regions with fast-growing populations.
At the same time, there is a need to increase global food production by 50 per cent in the next 30 years to achieve food security. These facts underscore the importance of developing global plant disease and precision agriculture monitoring methods that use advanced technologies. But the answer isn’t only to be found in technological advances, but also in collaborative research across disciplines. The future requires joint efforts between agricultural and engineering disciplines to create networks of hyperspectral sensors mounted on drones, as well as high-altitude drones and satellites that can concurrently screen for disease outbreaks and assess water and nutrient limitations at a global scale.