The News & Views article “Extinctions: A message from the frogs” by Andrew R. Blaustein and Andy Dobson (Nature 439, 143–144; 2006) stated that the mountain pine beetle Dendroctonus ponderosae transmits pine blister rust (Cronartium ribicola). In fact, the beetles are not a vector for the rust, but they preferentially attack trees already infected with the fungus.