A third disease which attacks the leading shoots of Hevea is known as die-back. This expression describes the nature of the disease with considerable accuracy. The fungus responsible for the disease is known as Gloeosporiutn cdborubrum. This fungus is microscopic, and its presence can only be recognised from its results. These, however, are not generally serious unless the dead shoots are attacked by another fungus, Botryodi-plodia theobromae, which, as a rule, cannot by itself attack living shoots.
When only the first named fungus is present, the dying back of the stem is confined to the leading shoots; fresh shoots grow out from buds lower down the stem to take the place of the dead branches, and but little damage is done. But when the Botryodiplodia obtains a footing, the disease pursues its downward way with great rapidity, and ultimately destroys the whole tree. Here, again, the only remedy is to cut off and burn the diseased portion. This should be done with a clean cut some distance below the lowest signs of injury, and the cut surface should be tarred.
Botryodiplodia has also been known to attack young stumps shortly after planting. In such cases the fungus probably effects an entrance through injuries in the stem or upper part of the root The holes in which the trees are planted should in such cases be treated with lime before supplying with fresh plants.