go 



pale reddish brown beneath black largely spotted with dull yellow. 

 The largest specimen was some inch and a half long. " The group 

 to which the caterpillar belonged is not stated, presumably it was 

 that of a Noctuid moth. The caterpillars were found to be numerous 

 on secondary jungle near the rubber fields. They were destroyed 

 by spraying with Paris Green in water. 



H. N. R. 



REPORT ON DISEASED RUBBER TREES 

 FORWARDED FROM PUAK. 



These saplings had the appearance of having been gnawed at by 

 some insect pest, but a close microscopic examination failed to 

 identify any such source of trouble. 



Thin sections of the stem and roots, when examined microscopi- 

 cally, presented an appearance shown in sketch. 



Longitudinal Section. 



The bark cells have undergone disintegration, 

 and in some cases the cambium layer has been 

 eaten into. 



Whilst the removal of bark from young 

 trees is in itself highly undesirable, anything 

 tending to reduce the vitality of the cambium 

 layer must be viewed with grave suspicion. 



Experiments were set in progress with the 

 object of detecting any fungi associated with 

 the diseased parts. Cultures were prepared by 

 inoculation therefrom on prepared and sterlized 

 potatoes and on Agar-Agar nutrient media. 



Within 24 hours vigorous growths appeared 

 on the latter, and on the second day a similar 

 activity was demonstrated on the potatoes. 



From these mixtures of fungi, the individual 

 organisms were separated, and pure cultures 

 prepared. In almost every case one sporiferous 

 bacillus predominated. 



Every precaution was taken during inocula- 

 tion to avoid contamination from without, but 

 it must not be overlooked that any soil is copi- 

 ously supplied with organisms, many beneficial, 

 and a few harmful, and also that the organisms 

 separated in the above experiments may have 

 been the sequence to, rather than the initial 

 cause of the trouble. 



It has been proved that the healthy rubber 

 tree is self — protective against most insect pests, 

 but no similar state of affairs has yet been 

 shown to exist for fungi. 



