334 



THE AGRICULTURAL NEWS. 



October 15, 1910. 



FUNGUS NOTES. 



SOME DISEASES OF RUBBER TREES. 



PART III. 



STEM DiSE.i.SE.s (continued). In the Bulletin of the 

 Straits and Federated Malay States, Vol. IX, p. 216, a short 

 account is given of a fungus which was observed on the 

 trunks of some dead trees of Hevea. It appeared in the form 

 of black and rather brittle crusts, each measuring -^- to 

 f-inch in thickness. These burst through the bark some time 

 after the trees were dead, causing the outer corky layers to 

 split off in flakes. Specimens were forwarded to Kew for 

 identification, and in reporting on them, Mas.see says: ' The 

 fungus proves to be an undescribed species of Eutypa, and 

 will be called E. raulivora. It is probably a true parasite, 

 judging from what is known lespecting other .species of 

 Evtj/pa, a constant feature of which is that the fungus per- 

 sistently remains in a vegetative — and thus aggres.sive — 

 condition, so long as its host remains alive, and only comes 

 to the surface to produce fruit when the host i> absolutely 

 dead. The numerous black streaks, deep in the wood of the 

 specimen sent, are produced by the mycelium of the fungus, 

 which in all probability permeated the whole of the wood, 

 and had been at work for a considerable period of time. Such 

 a development of mycelium is unknown as a post-mortem 

 result.' 



It is difficult to see what remedial measures can be 

 recommended, as the fungus gives no indication of its presence 

 until the tree is dead. Its spread could probably be arrested 

 by carefully destroying all trees that have died from its 

 effects. This disease has been dealt with at some length on 

 account of the fact that another species of the same genus of 

 fungi, Eutypa erumpens, Massee, has been found of late years 

 on several different host plants in the West Indies; among 

 these may be mentioned cacao, nutmeg, Barbados evergreen 

 (/'(>«.? sp. ), and several forest trees. It occurs in Trinidad, 

 Barbados and Grenada. It is thought to be a wound para,s- 

 ite, and produces symptoms very similar to those caused by 

 E. catdivora. (See also Kew Bulletin, 1910, p. 2.51.) 



In Bulletin 6 of the Department of Agriculture of the 

 Federated Malay States, Gallagher described a stem and 

 branch disease affecting Hevea trees in that country. This 

 attacks trees varying from three to eight years of age, and 

 spreads fairly rapidly. On young plants it seldom proves 

 fatal, but in the case of older ones, it frequentlj- necessitates 

 their destruction. The trouble is not so far very widespread, 

 although it appeared simultaneou.sly in several different locali- 

 ties. Corticiuin Zimmerrnannii{ = Cm-ticiuiii Jarayiicum), has 

 been found associated with the disease, but has not been 

 proved to be the cause. The attack usually commences 

 above the fork, on the stem or lateral branches. The finst 

 sign is the presence of tears of coagulated latex on the part 

 affected. The upper surface of a diseased branch appears 

 black and cracked, and has blotches of latex where the 

 fungus commenced its attack. The branch is soon ringed, 

 and consequently dies, the leaves at the same time dropping. 

 Diseased branches and portions of stem should be removed 

 carefully, and the wound so made, tarred. Young trees in 

 the neighbourliood of those attacked, should be sprayed with 

 Bordeaux mixture. 



In some instances in Ceylon, in 1905, it was found that 

 the horse-hair blight spread from tea plants to Hevea trees 



planted among them. The fungus is probably a species of 

 -Marasmius. (See Agricultural News, Vol. IX, p. 206.) 



A canker disease of Funtumia elastica, occurrinc in 

 Uganda, is described by Massee in the Eere Bulletin, 1909, 

 No. 3, p. 147. The trunk is attacked at a height of 4 to 6 

 feet above the ground, where a small black patch appears 

 in the bark, which extends until it covers an area of as much 

 as a foot or more. Later, the bark becomes thick, cracked 

 and rugged: if the fungus spreads completely round the trunk, 

 as may happen, the tree is killed. The disease is due 

 to a new species of Nectria, N. funfumiae, Massee., and is 

 similar to the canker of Hevea in Ceylon which was describ- 

 ed above. Massee considers that the same remedial measures 

 as are made use of in Ceylon would probably prove effective 

 in its control. (Agricultural A'ews, Vol. VIII, p. 185.) 



FRUIT DISEASES. A blackening and decay of Hevea 

 fruits was reported by Fetch in Ceylon, in 1905 {Circulars 

 and AgriciUtural Journal of the Royal Botanic Gardens, 

 Ceylon, Vol. Ill, p. 281). The disease was due to a species of 

 Phytophthora similar to that found on cacao pods in the 

 West Indies and other parts of the world. The same fungus 

 was also found on cacao and bread fruit in Ceylon, and 

 recorded by Fetch in the Administration Reports, 1906. In 

 view of Rorer's recent work in Trinidad, the possibility is 

 suggested that the canker of Hevea may be also primarily 

 due to the same species of Phytophthora. On the rotten 

 fruits, Nectria diversispora, Sphaeronaeina album, Fetch, and 

 Dijjlodia -.ehrina. Fetch, were found. These, in all probability, 

 bear the same relation to the disease of Hevea fruits as the 

 various species of Nectria do to the black rot of cacao pods, 

 that is, they are saprophytes. In 1906 the disease had 

 disappeared, mainly owing to the weather conditions. Care- 

 ful destruction of diseased fruits is recommended as 

 a preventive measure. 



SEEDLiSG DISEASES. Two important seedling diseases 

 of Hevea are known, one occurring in Ceylon, and apparent- 

 ly imported from that island into Borneo: the other, in the 

 Malay Peninsula. The first is due to the grey blio-ht 

 fungus, Fesfalozzia Guepini, Desm., which also attacks tea. It 

 occurs on the stems of seedlings at the collar, where it forms 

 a white ring round the stem, bordered by a narrow red-brown 

 line. The disease may also occur on the leaves of seedlings, 

 when it does but little harm, whereas when attacking 

 the stem it kills the plant. (Circulars and Agricultural 

 Journal o1 the Royal Botanic Gardens, Ceylon, Vol. Ill 

 p. 280; Aqricultural Bulletin of the Straits and Federated 

 Malay States, Vol. V, p. 400.) 



The seedling disease in Malay is due to a fungus which 

 attacks the leaves of young nursery plants and may cause very 

 serious damage. The leaves are deformed, being narrow and 

 inequilateral, with the nerves irregular, wavy, and ascending 

 towards the tip. Pale, whitish-orange patches of dead tissue 

 are scattered over the leaf. These are |^- to ^-inch across, of 

 irregular shape, and have a raised edge. Minute black dots 

 occur on the upper surface of these patches which, according 

 to Massee, are the fructifications of a .species of Cercospora, 

 though it was at first suggested that the fungus was a member 

 of the Uredineae. Bordeaux mixture and the careful removal 

 of diseased leaves would probably be found effective in dealing 

 with this trouble. (Agrictdtural Bulletin of the Straits and 

 Federated Malay States, Vols. Ill, p. 308; and IV, pp. 68 and 

 271.) 



LEAF DiHEASES. These diseases are of very little impor- 

 tance. Ileliiiinthosporiuiu heveae. Fetch, occurs on the leaves of 



