Infest sweeps their small creature suite (Birds of Paradise, Llanowar Elves, Basking Rootwalla, Wild Mongrel, Arrogant Wurm at 4 toughness survives but most others die) and can blow them out after a Survival of the Fittest tutor commits a creature to the board. Naturalize answers Survival of the Fittest itself along with Sylvan Library, cutting off their card advantage and tutoring engine. Llanowar Elves is weak to keep at full count since Infest will also kill our own mana dorks, so trim a couple; Duress has fewer profitable targets since most of their deck is creatures and lands, which it can't take, and once Survival of the Fittest or Sylvan Library has resolved it's too late for Duress to help. Keep Pernicious Deed as a critical answer to a wide board of cheap creatures, and it can also destroy Survival of the Fittest and Sylvan Library.