Movento is one of a couple products you can use, but I choose not to endorse chemicals specifically for liability issues. It is best to get exact recommendations for each state from their extension teams. Like others have said, spring is the time to apply it. Honestly in most cases the foliar phylloxera is more of a cosmetic fix than a physical one. It looks ugly but is not very serious for the vine. Marquette has wild American graps in it's genes and carries a resistance to phylloxera, so even though the vines can get it, it isn't serious.