View Dr Gretna Weste (1917-2006)'s photo gallery
You can order the DVD from the Academy for $15 (including GST and postage)
Dr Gretna Weste was interviewed in 2000 for the Interviews with Australian scientists series. By viewing the interviews in this series, or reading the transcripts and extracts, your students can begin to appreciate Australia's contribution to the growth of scientific knowledge.
The following summary of Weste's career sets the context for the extract chosen for these teachers notes. The extract covers Weste's PhD research on take-all fungus in wheat. Use the focus questions that accompany the extract to promote discussion among your students.
Gretna Weste was born in 1917 in Scotland, where her father was a volunteer chemist during World War I. The family returned to Australia when Weste was 2 years old. She attended Mont Albert State School and Methodist Ladies' College in Melbourne.
Weste received a BSc from the University of Melbourne in 1938 and an MSc in 1939. She then worked as a research officer in the Forest Commission from 1939 until 1942.
Between 1955 and 1960 Weste taught biology at Firbank Church of England Girls' Grammar School. In 1961 she began teaching in the School of Botany at the University of Melbourne. At the same time she started her research on take-all, a root fungus in wheat, receiving her PhD in 1968.
Weste continued to teach at the University of Melbourne until 1982. She remained interested in plant pathology but changed her focus of research to study Phytophthora cinnamomi, the cinnamon fungus, which causes dieback in many of the understorey plants of Australia's dry sclerophyll forests.
When she retired from teaching, Weste continued her research as a senior associate in the School of Botany. Over a period of time she was able to show that areas infected by the cinnamon fungus can regenerate. The University of Melbourne awarded her a DSc in 1983.
Weste was organised the Fourth International Plant Pathology Congress (1983). She received the Medal of the Order of Australia in 1989. She is an honorary Fellow of the Australasian Plant Pathology Society (1994), and was made patron of the Australasian Mycological Society in 1999.
Well, I instituted a number of changes in Biology I. For example, instead of the students just sitting doing descriptive work in the lab, I introduced little experiments whereby they had to measure things and draw conclusions from them. (And they always used to say, 'What answers should we get?') Also, I instituted tutorials on a problem basis. Each of the 15 or so students in the tutorial class had to write a paragraph on a problem I had set, to show whether they had understood the lectures. Then the demonstrator or lecturer taking the tute could go ahead, explaining what hadn't been clearly understood. And I put in carrels for self-help for those that had got behind or not understood, or had missed classes.
What was the subject of your PhD research, and who was your supervisor?
Peter Thrower left to become professor in Hong Kong, so I didn't have a supervisor. Professor Turner said, 'I'll be your supervisor, as long as you never come near me or ask me any questions, because I know nothing about your subject' – which was take-all in wheat. That is a root fungus.
The farmers were having great problems. Whole bands of the field were 'lodging' (that is, the plants were collapsing) and the ears were 'whiteheads', they had no grain in them. A new virus, barley yellow dwarf, had just been discovered and people were not sure whether it or the take-all fungus was causing all this damage. This was part of my problem.
Robert Koch, last century, had established certain postulates: you had to isolate the fungus from a plant with the symptoms, you had to grow it separately on agar jelly, and then you had to put it back in a healthy plant, get the same symptoms and re-isolate. If you did all that, you fulfilled Koch's postulates and you had proved your cause. I did it with the take-all fungus, which I found was causing the damage, not barley yellow dwarf. Take-all fungus was a worldwide problem in wheat fields. But why was it infecting these great swathes of wheat in Australia?
The old practice in farming all over the world had been to burn the stubble after a wheat crop, but farmers in Australia weren't burning it, they were turning the sheep onto it. The sheep would eat the top and leave that stubble sitting there where the fungus was. I found that that fungus needs light to produce its spores. Using cross-gradients of light and temperature, I found it needed blue light of quite a high value, 3000 ergs per centimetre per second. And in the swathes in the paddock, with the stubble eaten down, it was certainly getting all the light it needed and so it was producing lots of spores.
How then was it infecting the new wheat crop? I got photographs of these spores being produced and demonstrated that they were infecting the new wheat crop – and I found it was producing certain enzymes which were killing the plants. They started to grow, but then they collapsed as the fungus took over their roots.
I've always based my research on asking a question, thinking up several possible explanations and devising experiments to find which one was right, with perhaps one final experiment to prove it, and then publishing it. So I put in my PhD thesis in 1968.
Select activities that are most appropriate for your lesson plan or add your own. You can also encourage students to identify key issues in the preceding extract and devise their own questions or topics for discussion.
Caution: The three preceding experiments involve working with fungi (moulds). Because some people are allergic to fungi, follow all safety measures carefully (eg, keep the cultures enclosed and ensure that students wash their hands). At the end of the experiments, dispose of all cultures safely.
© 2025 Australian Academy of Science
