Occurrence of Sexual Reproduction of Daktulosphaira vitifoliae (Hemiptera: Phylloxeridae) in Southern Brazil and Biology and Fertility Life Table in Grapevine Cultivars.

The grapevine phylloxera Daktulosphaira vitifoliae (Fitch) is the pest insect of greatest importance in grapevine. The objective of study was to evaluate the occurrence of overwintering eggs in seedlings of 'Paulsen 1103' (Vitis berlandieri × Vitis rupestris) and evaluate the biology and fertility life table of D. vitifoliae on five grape cultivars: 'Bordô' (Vitis labrusca), 'Cabernet Sauvignon' (Vitis vinifera), 'BRS Lorena' (Vitis vinifera × Seyval [Seibell 5656-Rayon d'Or]), 'Magnolia' (Vitis rotundifolia), and 'Paulsen 1103'. In the field, overwintering eggs were found to be present in 78% of 'Paulsen 1103' seedlings, on the trunk of the seedlings. In the laboratory, phylloxera was found to complete the biological cycle (egg to adult) in roots of 'BRS Lorena', 'Bordô', and 'Cabernet Sauvignon'. Nymphs did not complete development on roots of 'Paulsen 1103' and 'Magnolia', with 100% first instar mortality. Adult females feeding on 'Bordô' roots showed the lowest total fecundity (20.9 eggs per female), differing from insects feeding on 'Cabernet Sauvignon' roots (207.8 eggs per female). Based on the fertility life table, roots of 'Cabernet Sauvignon' provided the best reproduction rate (Ro = 219), intrinsic rate of increase (rm = 0.197 d) and time between generations (T = 21.5 d). The presence of overwintering eggs on the trunk of the rootstock 'Paulsen 1103' may promote the survival and dispersal of the insect. Lignified roots of the rootstock 'Paulsen 1103' and the cultivar 'Magnolia' do not allow the development of D. vitifoliae, with 'Cabernet Sauvignon' being the most suitable for the development of the insect.