BOTANICAL SCIENCE
Citrus trees infected with Huanglongbing (HLB) can display mottled leaves featuring multiple hues of yellow and green
SCIENTISTS ARE USING A FASCINATING ARRAY OF NEW TECHNIQUES – NOT ALL OF THEM HIGH-TECH – TO DETECT AN EVER-EVOLVING ARMY OF PERNICIOUS PLANT DISEASES. DR BRETT SUMMERELL REPORTS.
T
he introduction of a diseasecausing organism can have a huge effect on the management of a garden – impacting what plants can be grown, where they can be grown and even if visitors can be allowed into an area. The implications for all gardeners are enormous. When I first started as a plant pathologist at the Gardens more than 30 years ago, I had a responsibility to diagnose diseases in the collections at the three Gardens. At that time the techniques available to me were relatively primitive and rudimental.
22 THE GARDENS SPRING 2021
I could look at the symptoms expressed by the plants, try to isolate pathogenic organisms, which might in some cases take weeks, and make decisions based on a combination of experience and instinct, combined with some science. Today we have a range of techniques that can be employed to detect the presence of pathogens accurately, precisely and in a remarkably short period of time. Eighteen months ago, few in the media or the broader community were particularly interested in pathogens. Now, thanks to COVID-19, it seems everyone is
interested and – to various degrees – informed on issues such as quarantine, genomics and mutations. All of these factors are also critically important when it comes to the detection and management of plant diseases – and in fact many of the techniques mentioned above were first developed for plant health diagnostics. At our own PlantClinic we have moved to using DNA-based techniques for the detection of plant diseases for almost all the disease diagnostics we undertake. With these techniques we provide a service that is faster, more accurate
Photos: Dr Nerida Donovan, Department of Primary Industries, Shutterstock
IN DEFENCE OF PLANTS
