- Since phylloxera's discovery in a commercial vineyard in August of 1990, nine infestations have been verified in Oregon. With over 95% of Oregon's vineyards planted with ownrooted, Vitis vinifera, non-resistant vines, understanding the insect's biology under our conditions has become important for determining management strategies that minimize rate of spread. Three infested vineyards were sampled bi-weekly in the Willamette Valley during the growing seasons of 1992 and 1993. Root samples were brought back to the lab and extracted through a sieve centrifugation method. Life stages, separated into egg, nymph, nymph/adult (later instar nymphs), and adults, were counted in petris with a 70x dissecting scope. Profiles of insects over time have been used to detect the appearance of certain life stages and determine the number of generations per year. A second experiment was conducted in the lab to determine the low temperature threshold of the three phylloxera populations. Insects were reared on Pinot Noir roots in incubators at five temperatures (7, 10, 13, 16, 21* Q. Insect survivorship and generation time were monitored with weekly assessments over a six week period.