RT Journal Article SR Electronic T1 Scientific Opinion: Improving the Definition of Grape Phylloxera Biotypes and Standardizing Biotype Screening Protocols JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 371 OP 376 DO 10.5344/ajev.2016.15106 VO 67 IS 4 A1 Forneck, Astrid A1 Powell, Kevin S. A1 Walker, M. Andrew YR 2016 UL http://www.ajevonline.org/content/67/4/371.abstract AB Grape phylloxera biotypes are defined by their specific performance on, or preference for, a particular host (e.g., feeding on a particular rootstock). Numerous studies have phenotyped phylloxera biotypes, particularly with regard to their performance on various hosts, but the results are difficult to compare because there is neither a homogenous nomenclature nor a standardized protocol for phenotyping. To improve communication within the scientific community, we offer a simplified phylloxera biotype classification to allow clear data interpretation and effective communication. We also introduce the standard techniques employed for phylloxera phenotyping and discuss their advantages and disadvantages.