The fungus Ustilago maydis attacks corn and can cause significant damage to its host. To do this, it first ensures that the plant offers little resistance to the infection. The surgical precision it applies is shown by a new study.The fungus Ustilago maydis attacks corn and can cause significant damage to its host. To do this, it first ensures that the plant offers little resistance to the infection. The surgical precision it applies is shown by a new study.