Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2001
Publication Date: October 1, 2003
Citation: Fisher, J.R., Albrecht, M.A. Constant temperature life table studies of populations of grape phylloxera from Washington and Oregon, USA. Acta Horticulturae. 2003. v617 p. 43-48. Interpretive Summary: Grape phylloxera is a recent pest threatening to destroy over 27,000 acres of 'self-rooted' winegrapes in the Pacific Northwest region of the USA. Some vineyards have coexisted with the pest for over 15 years while others have been devastated in less than 5 years. We conducted this study to determine if populations of these insects from four different areas in the Pacific Northwest differed in development time or survival when exposed to a myriad of constant temperatures (3-36 degrees C at 3 degrees intervals). Individual differences were observed among the four populations for egg hatch, larval development time, and survival for some of the temperature regimens. However, for these parameters all populations followed a general trend among temperatures. Earlier, we had found that, genotypically, these populations were similar. We now conclude that, biologically, these populations are similar and thus, ,differences in 'virulence' seen in vineyards are probably attributable to other factors.
Technical Abstract: Grape phylloxera is a recent pest threatening to destroy over 11,000 ha of self-rooted winegrapes in the Pacific Northwest region of the USA. Some vineyards have coexisted with this pest for over 15 years while others have been devastated in less than 5 years. We conducted this study to determine if life processes of populations of phylloxera from four different areas in nthe Pacific Northwest, USA, would show differences in survival, developmen and reproduction when reared at myriad of constant temperatures (3 - 36 degrees C at 3 degrees intervals). Individual differences were observed among the four populations for development, survival and reproduction. Nevertheless, the numbers for each parameter followed a general trend among temperatures. The optimum temperature range for maximum response for all parameters was between 24 degrees C and 27 degrees C. Upper and lower temperature thresholds were, respectively, less than 6 degrees C and greate ethan 33 degrees C. The results from this study and others support the hypothesis that localized differences in 'virulence' of infestations from vineyard to vineyard over an appellation may be a function, in part, of localized temperature differences caused by such factors as soil type, aspect, slope, pruning, ground cover, and plant spacing.