Filoxera-da-videira: biologia, resistência de genótipos, interação com o fungo Dactylonectria macrodidyma e controle químico

Abstract

The grape phylloxera Daktulosphaira vitifoliae (Fitch, 1856) is the main grape pest. The insect develops on leaves (forming galls) and roots (root galls). Permanent feeding on the roots results gradual decline and increased susceptibility to soil fungi culminating in the death of plants. One of the main strategies for pest control is the use of resistant rootstocks. The objectives of this work were: a) to evaluate the occurrence of “winter eggs” in ‘Paulsen 1103’ seedlings in the field; b) study the biology in roots of different cultivars and calculate the insect's fertility life table; c) to evaluate the resistance of genotypes of Vitis spp. phylloxera using the root excised method in the laboratory; d) to study the interaction of D. vitifoliae with the fungus Dactylonectria macrodidyma; e) to evaluate the effect of chemical insecticides on suppression of phylloxera populations on grapevine leaf and roots. The presence of phylloxera winter eggs was registered in 78% of the plants of the ‘Paulsen 1103’ rootstock sampled. In plants with the presence of winter eggs, an average of 31 ± 6.31 (X ± EP) eggs / plant was found. The phylloxera completes the biological cycle (egg to adult) in lignified roots of 'BRS Lorena', 'Bordô' and 'Cabernet Sauvignon', with greater viability of the period (90,2%) in roots of 'Cabernet Sauvignon'. The nymphs did not complete their development in lignified roots of ‘Paulsen 1103’ and ‘Magnolia’. Cultivars of origin or crosses with V. vinifera showed a greater number of tuberosities, while those of American origin (V. labrusca, V. berlandieri, V. rotundifolia, V. rupestris, V. riparia) promoted nodosities. Among the cultivars, the largest number of surviving insects was recorded in ‘Cabernet Sauvignon’. In contrast, the genotypes ‘548-15’, ‘Magnolia’ and ‘1111-21’ showed reduced infestation and survival of nymphs in the roots, being considered resistant to the pest. Roots infested with phylloxera and inoculated with the fungus D. macrodydima resulted in a higher percentage of reisolation of the fungus. In the chemical control test of phylloxera in the leaves, an application of the insecticide flupiradifurone (Sivanto®Prime 200 SL, 75mL pc / 100L-1 ) provided reduced foliar damage 90% at 28 DAA, while for thiamethoxam (Actara 250 WG ®, 40g pc / 100L-1 ), and sulfoxaflor (Closer®SC, 40mL pc / 100L-1 ) 3 and 2 applications were necessary to obtain the same level of control, respectively. For the root phylloxera, the insecticides sulfoxaflor (0,3mL / plant) and imidacloprid (Provado 200 SC, 0,7mL / plant) showed 10 the best results, with 96 and 89% control of nymphs + adults respectively, followed by flupiradifurone (0,8mL / plant) with 76%. In conclusion, the presence of winter eggs in the trunk of vine plants can be a source of dispersion of the pest for different producing regions of Brazil. The best biological performance of the insect is verified in 'Cabernet Sauvignon' roots. The genotypes '548-15' (V. labrusca x V. rotundifolia), 'Magnólia' (V. rotundifolia) and '1111-21' (V. labrusca x V. rotundifolia) have reduced pest infestation and can be used in selection new resistant rootstocks. There is an interaction between the grape phylloxera and the fungus D. macrodydima in roots of ‘Cabernet Sauvignon” in the laboratory. The insecticides flupiradifurone and sulfoxaflor are alternatives to neonicotinoids for the chemical control of phylloxera in the grape culture.