The diseases and pests of the rubber tree . of time. In the Federated Malay States it is recorded that Ustulina enters the stem through the shat-tered ends of largebrancheswhichhavebeen broken off bysome means orother. Such brokenends should be cutoff flush with thestem, and the ex-posed wood tarred. Whenever thestem of the Eubbertree has beendamaged it is liableto be attacked byUstuli)ia, but it isvery noticeable, atleast in Ceylon, thatsuch attacks usuallyoccur on diseased or damaged areas on which the previouslyaffected bark has remained more or less in situ, has notfallen off and expo
The diseases and pests of the rubber tree . of time. In the Federated Malay States it is recorded that Ustulina enters the stem through the shat-tered ends of largebrancheswhichhavebeen broken off bysome means orother. Such brokenends should be cutoff flush with thestem, and the ex-posed wood tarred. Whenever thestem of the Eubbertree has beendamaged it is liableto be attacked byUstuli)ia, but it isvery noticeable, atleast in Ceylon, thatsuch attacks usuallyoccur on diseased or damaged areas on which the previouslyaffected bark has remained more or less in situ, has notfallen off and exposed the wood. For example, in the case ofClaret-coloured Canker the disease may stop after extending tothe wood over a large area, and the dead bark may remainadhering to the stem. If these wounds are not cleaned upthey are frequently attacked by Ustulina. On a properlyconducted estate this, of course, does not happen, but it isby no means uncommon to find extensive developmentsof the fructifications of Ustulina on neglected canker patches. Fig. -Uslxdina zonata; fructification on Heveastem. xj. 144 THE RUBBER TREE chap. on small native holdings. The fungus works into the woodand kills the tree by destrojdng the wood right across thestem, but before that happens there may be a large cavityformed, extending from the originally diseased side deepinto the wood. The diseased wood is permeated by blacklines. Attacks of Ustulina also occur commonly on trees whichhave been scorched. Here, again, the damaged bark fre-quently remains in situ for a long time. Such trees arequickly attacked by boring beetles, and Sharpies considersthat the fungus follows the beetles, and that .its spores maybe introduced by them into the tree. The fructification of Ustulina zonata has been describedin the chapter on root diseases. Another fungus of an aUiedgenus also occurs frequently on old canker wounds and onscorched trees, and apparently produces the same effect asUstulina. Its fructification app
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