ABSTRACT
Cryptoblabes gnidiella (Millière) (Lepidoptera: Pyralidae) has been known in Uruguay for 30 years and only in vineyards, despite being polyphagous. In recent years, this pest has caused sporadic but serious damage on some grapevine cultivars. Understanding the insect's phenology and developing a monitoring program are essential aspects of integrated pest management. We monitored males using sexual pheromone traps on four cultivars of vine, Pinot noir, Tannat, Gewürztraminer, and Cabernet Sauvignon, in two vine-growing establishments in the Department of Canelones and compiled data on the accumulated effective temperatures for the southern area of Uruguay. We determined that this species undergoes three generations per year and overwinters without diapause as larvae on dried grapes remaining after harvest. Using the proportion of cumulative male moths caught from December to May from 2003-2007 on the four cultivars and the sum of effective temperatures above two previously-published lower-threshold temperatures for development, 12.26°C and 13°C, statistically significant logistic models were estimated. Predictions based on the resulting models suggested that they would be acceptable tools to improve the efficiency of integrated management of this pest in Uruguay.
ABSTRACT
Grapevine phylloxera, Daktulosphaira vitifoliae (Fitch) (Hemiptera: Phylloxeridae) is a worldwide pest of Vitis species. It has forms that feed on leaves and roots. Root forms predominate on Vitis vinifera (L.) cultivars, while leaf forms predominate on Vitis species from its native American range. Recently, high densities of D. vitifoliae infestations in leaves of V. vinifera in Brazil, Peru, and Uruguay have been reported. The aims of this study were to determine the seasonal development of grape phylloxera, quantify infestation levels on V. vinifera leaves, and compare them with infestation levels on leaves of a rootstock of American origin. Studies were conducted in two vineyards in Uruguay from 2004-2007. Terminal shoots of 3309 C and Cabernet Sauvignon, Chardonnay, Tannat, Viognier, grafted onto resistant rootstock, were sampled weekly and leaves examined for gall presence and insect life stage. First galls were detected in early October; eggs began to appear within two weeks. Two oviposition peaks occurred by the end of December, and they coincided with bursts of shoot growth. On 3309C rootstock, oviposition peaks were more frequent than on the European cultivars. Based on thermal accumulation, D. vitifoliae could complete eight generations a year in Uruguay. Rootstock 3309C suffered the greatest damage but in some cases was similar to the European cultivars. Damage to Chardonnay, Cabernet Sauvignon and Viognier were also high. There were no galls on Tannat. The 2005-2006 season was characterized by low infestation rates caused by a prolonged drought that affected vegetative growth. There were also differences between vineyards, where the vigorous plants suffering more damage. Leaf galling phylloxera incidence and damage were mainly associated to the cultivar but plant vigor and environmental factors also contributed to increase the incidence.
