397 



blown over by stronger winds than usual. As a rule, it is impos- 

 sible to detect the fungus before the tree is uprooted. Saplings die 

 before the mycelium reaches the surface. In the majority of cases 

 the fungus appears to be identical with that reported from the Straits 

 in 1904, viz., Fomes semitostus , Berk. No fructifications have been 

 found in the field, but several have been grown at Paradeniya on 

 diseased stumps from affected areas. This species spreads under- 

 ground alon^, the roots of grasses, etc. In ont- instance the fungus 

 was Poria vincta, B. & Br., it seems impossible, however, to dis- 

 tinguish the two by mycelium alone. 



A third root fungus which attacks Hevea is practically omni- 

 vorous, specimens having been sent in a cacao, dadap, tea, Castilloa, 

 and Caravonica cotton. The mycelium only has been observed : 

 this forms a yellow-brown or whitish felt on the root to which stones, 

 etc., adhere firmly. It seems to be identical with the cacao root 

 fungus prevalent in Samoa and attributed to Hymenochoete, sp. 



It should be noted that all these root fungi are common on dead 

 wood or stumps in the jungle and spread to cultivated products from' 

 stumps in cleaning. 



Stem Diseases. — With regard to canker, the outlook is decidedly 

 improved. Excision of diseased tissue has* in all cases proved 

 efficacious, without injuring the subsequent growtli of the tree. At 

 the beginning of the year, when I wished to become acquainted 

 with this disease in the field, I had great difficulty in finding an 

 affected tree. It must not be thought, however, that the periodic 

 inspection of trees is now unnecessary, the disease may easily be 

 kept in check if the first stages are noted, but neglect result in the 

 death of the tree. I have seen a 12 years' old tree completely killed 

 by it. The Government plantation near Badureliya was inspected 

 in June after the jungle had been cleared awaj 7 , and again in July 

 when the trees were being tapped. Hardly any "canker" was 

 found on either occasion. A few facts which may throw further 

 light on the origin of the disease have been ascertained. The nec- 

 tria on the dead bark has been named Nectria diver sispora. 



Megalonectria pseudotrichia (Schw), Speg., was observed in one 

 instance on living branches of Hevea. 



Fruit Diseases. — The blackening and decay of Hevea fruits which 

 has been a constant feature during the last few years was exception- 

 ally prevalent in June, and gave rise to the fear that there would be 

 a shortage in the crop, but a dry July stopped the disease almost 

 entirely, and the price of seed dropped in consequence from Ss. 30 

 to &s. 2 per thousand. This disease is due to a Phytophthora, 

 similar to that found on cacoa pods in other countries. On the 

 rotten fruits grow Sphoeronoema album, n. sp., Nectria diver sispora, 

 n. sp., and Diplodia zebrina, n. sp. There is no doubt that this 

 decay will always occur in wet seasons, and to minimize the pos- 

 sibility diseased fruits should be collected and burnt. It is not 

 possible to form any opinion as to the success of the other preven- 

 tive measures employed owing to the exceptional weather conditions 

 of the last season. 



