Arnold, Kari Lynn (2016). The sociological, epidemiological, and ecological aspects of virus management in California vineyards. Doctoral dissertation (Plant Pathology), University of California, Davis. (Note: This dissertation is comprised of four separate and interrelated studies, only one of which involves Q methodology and each of which carries its own abstract and Reference section.)

“Using Q-method to understand wine-grape grower’s subjectivities in reference to managing Grapevine leafroll associated virus-3 (GLRaV-3)” (pp. 26-49).

Abstract: Regional, or area-wide, management is an important tool in slowing the spread of vectorborne plant viruses. Successful area-wide treatment requires cooperation among growers but this means that not only objective information about the problem, but also the subjective opinion of the cooperating individuals is important to the success of the effort. We studied the subjective opinion of 37 winegrape growers and vineyard managers in the Napa and Sonoma Counties of California using Q-method to carry out a Q-sort of 47 statements about virus disease management and certified planting stock. A second group of 12 participants from the Lodi and Bakersfield/Wasco regions who work in the grape nursery business also carried out Q-sorts on the same set of statements. Principal Components Analysis of the Q-sort data revealed that there were no strong groupings of opinion among the 37 growers/managers, but they could be allocated to broad categories depending on whether they were problem- or solution-oriented, whether they focused on financial or technical issues and whether they had an open or closed attitude. In spite of appearing as a diverse group, the relative similarity of the 37 grower/managers was revealed by projecting the 12 nursery grower/managers into the Principal Component space defined by the winegrape growers. The two groups of individuals were found to be widely separated, principally by the emphasis placed on technical issues connected with clean plant use. However, despite the diversity of opinion among all 49 respondents, a group of six statements was identified which were consistently ranked as important. These statements focused on the role of certified planting stock in virus management and the need to prevent virus spread among blocks.

Kari Lynn Arnold <> is currently a post-doctoral scholar at the University of California, Davis.

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