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​​​Bugging out in the vineyard: Getting to the root of phylloxera management in Victoria, Australia​​​

​Instructor Resources​

Case summary​

The focus of the case is on choosing the type of wine grape vines to plant in a newly-established vineyard, with the option of either Vitis vinifera scion material grafted onto phylloxera-resistant rootstock or own-rooted phylloxera-resistant non-Vinifera grape cultivars. The case is set in Victoria, Australia, which also introduces the students to a system of area wide pest management known as phylloxera management zones. The case discusses long-term planting decisions, high investment risk, a lack of effective pesticides and biological control options, mechanisms of phylloxera spread, origins of grapevine resistance, grafting options, labor inputs, and impacts on grape and wine quality and marketability. The case study presents students with what appears to be a straightforward either/or decision, but one which ultimately pushes them to weigh all of these factors and more.

Suggestions on how to use this case​

The case study was tested in a 50-minute class period by remote instruction (via Webex) to Iowa State University HORT/FSHN 276, “Understanding Grape and Wine Science" on February 26, 2021. Class size was 11 undergraduate students from majors including horticulture, agronomy, environmental science, biology, and agricultural engineering. Students were provided with the case and the background information four days in advance, and were also given a short homework assignment based on the readings.

At the beginning of the class period, a 5-minute intro presentation was given to refresh students' recall of key points from the readings. Students were then split into “breakout sessions" in Webex to discuss the following in small groups: 1) a brief summary of the case, 2) the 1-3 most important considerations for decision-making, 3) the group's decision and reasoning. After 10 minutes, students returned from breakout rooms to present their group's answers to the whole class and discuss. Students were again put in small-group breakout rooms, with each group assigned one of the following questions: 1) Why are awareness campaigns about phylloxera spread important? 2) After planting, would you continue to monitor for phylloxera? If so, how would you do it? 3) What would you do if phylloxera did turn up in your new vineyard? Students again returned to the full class and presented their group's answers for discussion. Presenting the case study in a fully virtual format worked well, although in-person delivery would have some advantages in terms of interpersonal engagement. In this course, the students brought up a wide range of viewpoints, ideas, and considerations. They also demonstrated a high level of engagement with the information and the problem.

Student responses to a Qualtrics survey indicated that the aspects they found most helpful were reading the case study itself prior to class time, reading the provided background information prior to class time, and participating in small-group discussions during class time. Student suggestions for making the case study more effective for learning included more information on varying levels of resistance, emerging biotypes, the pest's lifecycle, and the phylloxera situation in other grape-growing regions. To avoid burying students in too much extra information, we have chosen to retain the balance of detail as it was presented. However, we strongly encourage instructors to emphasize the background information provided as well as the other resources listed for students who wish to delve deeper into a specific aspect of the topic. Suggested discussion questions are included, but should be tailored to the particular group of students to best facilitate engagement.

Learning outcomes

1. Understand impacts (symptoms, history) of phylloxera on grapes
2. Understand pros and cons of various ways to manage phylloxera
3. Understand how the choices of grape cultivar and rootstock material influence the risk of phylloxera infestation
   
4. Consider how geography and human activities impact phylloxera risks and management strategies
5. Consider unique challenges associated with long-lived crops such as grapevines