268 PHYTOPHTHORA MEADTI Tl. sp, ON HEVEA BRASILTENSIS 



Hevea stems. Three out of the ten inoculations with spores suspended in water 

 produced canker, and three inoculations with pieces of diseased cacao pods 

 also produced (banker. He accordingly concluded that the canker and pod- 

 disease of Hevea are both caused by Phyto^Miora , and that the species is the 

 same as that which causes pod-disease and canker in cacao, viz., P. Faberi 

 Maub. He also described a bark-rot that occurred during the prolonged rains 

 of 1909-1910, and thought that it did not appear to be due to canker. Thus 

 in 1910 in Ceylon fruit-rot, a die-back of the fruiting branches, claret-coloured 

 canker, and bark-rot were reported on Hevea, and the cause of the first three 

 was attributed to P. Faberi, while the last was thought to be due to physiolo- 

 gical causes correlated with excessive rainfall. In his book he gives the 

 various symptoms in detail. In 1912-13 Petch^ says that it has been found 

 that the leaf-fall which often follows the fruit-disease, and is characterised by 

 the appearance of a dark-brown ring on the leaf-stalk, is caused by the canker 

 fungus (P. Faberi), and in 1914 he^ states that canker was first recorded 

 in Ceylon in 1903, so that the causative fungus P. Faberi has been found to 

 attack every part of the tree except the leaves, though it attacks the leaf-stalks, 

 and causes defoliation. In 1916 he^ associates the fruit disease and the 

 consequent leaf -fall as caused by the same fungus. He also states that it has 

 been shown that the fungus produces resting-spores in the diseased pods, and 

 remains dormant in branches partly killed back. In various subsequent 

 references he reiterates the above statements. Thus in Ceylon the disease 

 attacks fruits, leaf -stalks, green-branches and fruiting-stalks (causing a partial 

 die-back), bark and renewing bark, and causes a general leaf- fall in the monsoon, 

 and all the symptoms are attributed to the action of P. Faberi. In South 

 India I have never seen claret-coloured canker, but the other symptoms are 

 exactly as they are found here, though the causative fungus is a difTeient species 

 of Phytophthora ; and taking into account the discussion on a previous page, it 

 seems possible that the causative fungi in Ceylon and South India are different. 

 Still as Dastur suggests from a consideration of the literature, it may be that 

 P. Faberi in Ceylon causes claret-coloured canker only, and that the species 

 causing the other symptoms has not yet been definitely determined, especially 

 if in 1916 Fetch means that resting-spores have been found in diseased fruits 

 in Ceylon, and the resting-spores are oospores. As the resting conidia of 

 P. Faberi were so readily produced by the fungus on inoculated Hevea fruits 

 as well as on cacao pods, and as there is nothing to show that they are oogonia 



1 Fetch, T. "Admimstration Report of the Dept. of Agric, Ceylon," p. 7, 1912-1:}; p. G, 1910. 

 ^ „ " Lxternational Rubber Congress met Tentoonstellig, Batavia," pp. 12 — 14, 1914. 



^ „ " Diseases of //et-ea ". Trop. Agric, XLVII, pp. 279—28}, 19l(i. 



