In many countries, the numbers of fig trees have been declining. While there are numerous explanations, one key problem is fig-wilting disease. A recognized cause of this disease is a fungus, Ceratocystis ficicola, which is transmitted by an ambrosia beetle, Euwallacea interjectus. Now, a group from Nagoya University in central Japan has identified another fungus, Fusarium kuroshium, which is harmless by itself, but ravages fig trees when found together with C. ficicola. Along with known agents, such as C. ficicola, many other fungi are believed to be important in fig-wilting disease. These include F. kuroshium, a well-known infective agent of fig and avocado trees. As these fungi are frequently found on the heads, including a special organ for storing fungi, of wild and reared E. interjectus adult female ambrosia beetles, it has long been suspected that they are responsible for the spread of disease.