Asiatic brown rot, caused by the fungus Monilia polystroma, is native to Japan. Unlike our native brown rot which infects primarily stone fruit, Asiatic brown rot readily infects apple and pear. Asiatic brown rot has been introduced into China and Hungary where it is affecting apple orchards. The fungus travels from place to place on infected plant material – young trees, nursery stock, and fruit. Because brown rot fruit infections can be latent (essentially invisible), people can unknowingly bring the disease into the U.S. from other countries.