172 



As in all cases of root disease there is hardly an efficacious remedy. 

 Watering the soil with disinfectant will injure the plants and the rem- 

 edy may be worse than the disease. On the contrary improving the 

 conditions of cultivation, especially the drainage where the soil is 

 moist, is of the first importance. The diseased plants must be pulled 

 up and burned, the infected spots must be worked over several times 

 with lime, and Hevea must not be again planted before the soil is 

 certainly disinfected. The disease rarely shows itself on plants put in 

 a virgin soil, but on the contrary always in those planted in an 

 exhausted soil. (It is very common on trees in virgin soil in the 

 F. M. S. Transl). The infected areas may be with advantage isolated 

 from the rest by trenches in which lime is scattered. When the 

 disease is suspected the soil should be doused frequently w T ith a 

 solution of lime in water. This cheap procedure is very effective 

 because it renders the soil alkaline which condition is not favourable 

 to the growth of fungi. 



(c) . Fusicladium, sp : Black Canker. Material showing a black 

 canker of the stem has been several times sent in for examination. 

 The fungus appears to belong to the genus Fusicladium. The disease, 

 which is not yet serious, occurs on the cut ends of branches or stems 

 left by pruning. The leaves fade, dry up, become yellow, and fall off ; 

 the flow of latex diminishes rapidly, and soon ceases totally ; in a few 

 days the plant is dead. Sometimes only the higher parts die and new 

 branches come out below." Cryptogamic parasites of less importance 

 mentioned by the author are 



(d) . Pestalozzia Palmar um which has been frequently noticed 

 on the leaves of Hevea. 



(e) . StUbella Hevea, (Zimm.) Bern. According to Zimmerman 

 this is probably not a parasite and the other thinks it of little import- 

 ance as far as Hevea is concerned. The author goes on to comment 

 on (f) lalang, (g) piercing insects on young nursery plants, (h) boring 

 insects, (i) white ants (termites), (k) red ants, and (l.m.n) other pests 

 such as caterpillars and pigs. 



W T hite ants in Java are not, the author says, directly injurious, 

 and do not generally attack healthy vigorous plants. He recommends 

 sprinkling the base of the trunk on which they appear with Solignum. 



Among the enemies of Ficus elastica (Rambong) the author gives 

 " lalang " the first place mentioning Zimmerman's opinion that there 

 is only one real cryptogamic parasite of Ficus elastica, namely 

 Nectria gigantospora, and this the author has not met. 



Certain areas on a Ficus plantation were suffering from a disease 

 of an unknown nature. All the plants over a considerable area had an 

 unhealthy appearance ; the yellow withered leaves were rapidly drop- 

 ping off. An examination of the unhealthy specimens failed to dis- 

 cover in the leaves, branches or stem a parasite to which the disease 

 could be attributed. The defective turgescence of the leaves and their 

 premature fall are rather the appearances which characterise a plant 

 weakened by unfavourable conditions of existence. On all the areas 

 attacked lalang had reached a good development, and it was clear that 

 this undesirable plant was the origin of the trouble. When lalang is 

 abundant it not only exhausts the soil of nutritive materials but 



