Population dynamics of grape phylloxera in California vineyards
DOI:
https://doi.org/10.5073/vitis.1997.36.199-205Keywords:
grape phylloxera, Daktulosphaira vitifoliae, grapevines, population, growth, distributionAbstract
Field monitoring was conducted to investigate population growth of grape phylloxera, Daktulosphaira vitifoliae (Fitch), in commercial grapevines in California. Phylloxera populations started from very low densities each spring, they increased exponentially and peaked during mid-summer, and then declined from mid-to late-summer. A second population peak was observed in the fall. Populations increased and declined simultaneously across all age classes. Egg populations were highest, followed by 1st and 2nd and then 3rd and 4th instars; adult populations were the lowest. The distribution of age classes as a proportion of the total population indicated a higher intrinsic rate of increase in field vines in spring and early summer than was observed in the laboratory. Densities of phylloxera on tuberosities were highest during the summer and coincided with the population maximum. Densities of phylloxera on nodosities were highest in early spring and in the fall and coincided with periods of root flush. Evaluation of the relationship of soil temperatures to developing phylloxera suggested that decline of phylloxera populations in mid-and late-summer cannot be attributed to temperatures below a developmental threshold. Decreased root quality or quantity and mortality factors may explain this decline. Phylloxera overwintered as 1st or 2nd instars. Analysis of spatial distribution of phylloxera using Taylor's power law and Iwao's patchiness regression indicated that phylloxera populations are aggregated. The significance of this research with respect to phylloxera management is discussed.Downloads
Published
Issue
Section
License
The content of VITIS is published under a Creative Commons Attribution 4.0 license. Any user is free to share and adapt (remix, transform, build upon) the content as long as the original publication is attributed (authors, title, year, journal, issue, pages) and any changes to the original are clearly labeled. We do not prohibit or charge a fee for reuse of published content. The use of general descriptive names, trade names, trademarks, and so forth in any publication herein, even if not specifically indicated, does not imply that these names are not protected by the relevant laws and regulations. The submitting author agrees to these terms on behalf of all co-authors when submitting a manuscript. Please be aware that this license cannot be revoked. All authors retain the copyright on their work and are able to enter into separate, additional contractual arrangements.