EFFICACY OF PESTICIDES ON GRAPE PHYLLOXERA POPULATIONS IN VITRO AND IN SITU

The efficacy of three insecticides was studied on grape phylloxera survivorship and fecundity using a root bioassay; the most promising compound was further studied under field conditions. Spirotetramat did not allow nymphs to develop to adulthood in the root bioassay. Phylloxera reached the adult stage by the 19th and 21st days after 1-6 day old eggs were placed on excised roots treated with abamektin and thiamethoxam, respectively. Spirotetramat was tested under field conditions using own-rooted Vitis vinifera ‘Chasselas rouge’ and ‘Chasselas blanc’. The number of colonies was reduced with foliar spray application of spirotetramat when post-treatment sample vine roots were compared to pre-treatment root samples. Treated plants displayed more vigor, but more years of testing are needed to verify that vineyard health is consistently improved.