Resistance of Grapevine Genotypes (Vitisspp.) toDaktulosphaira vitifoliae(Hemiptera: Phylloxeridae) in Brazil: Implications for Pest Management

The phylloxera Daktulosphaira vitifoliae (Fitch) is considered the main pest in vine crops in the world. One of the alternatives for pest management is the use of resistant rootstocks. In the present study, 14 vine genotypes comprised of 6 canopy cultivars (Bordô, Isabel, BRS Lorena, Cabernet Sauvignon, Magnólia, and Chardonnay), 4 commercial rootstocks (Paulsen 1103, SO4, IAC 766, and IAC 572), and 4 promising rootstocks for pest management (1111-21, 548-44, 548-15, and IBCA-125) were evaluated for resistance to infestation the of root form of pest. For each genotype, the number of eggs, nymphs, and adults present in the roots were evaluated at 15, 20, 25, 30, and 35 d after egg infestation. In addition, the feeding place (lignified or nonlignified root), the presence or absence of tuberosities and nodosities, and the total fecundity of females were evaluated. The highest survival rates of nymphs and adults were observed in Cabernet Sauvignon, BRS Lorena, Chardonnay, and IBCA-25 in lignified roots, with the formation of tuberosities characterizing the materials as susceptible. In contrast, SO4, Paulsen 1103, IAC 572, IAC 766, 548-44, 548-15, Magnólia, and 1111-21 provided the least nymph and adult survival over time in nonlignified roots present in the nodosities, characterizing the materials as resistant. In addition, the lowest fecundity was observed in the roots of Magnólia (16 eggs). According to the results, it was verified that the cultivar Magnolia and the selections 548-15 and 1111-21 present reduced infestation and survival of nymphs of D. vitifoliae in the roots. This fact demonstrates the potential of the materials to be used as new resistant rootstocks or sources of insect resistance.