61 



A careful watch should be kept both on timber and rubber trees 

 and stumps for the fructifications of the fungi mentioned, the most 

 dangerous being those of Usttilina, those should be destroyed as soon 

 as the}' appear. Rubber stumps left after thinning out often bear a 

 plentiful crop of JJstulina fruits — the practice of felling trees by 

 severing the laterals has much to recommend it, the roots left 

 behind soon decay, and there is no chance of harmful fungi being 

 harboured. 



Admittedly the measures proposed above, involve an increase in 

 expenditure. When considering the benefits conferred by immunity 

 to disease, it should be borne in mind that, given time, contact 

 diseases spread at what may be called " compound interest," i.e., the 

 number of possible infections grows rapidly as the disease spreads 

 out from the centre of the infection. 



No figures have been given for costs of clearing, etc., as 

 conditions vary too widely to make comparison reliable ; it is, 

 however, the emphatic opinion of tlie mycologists of the Department 

 that the measures outlined above will be found in every case to be 

 abundantly justified. 



Discussion. 

 Tlie Chairman (Mr. Lewton-Brain) invited discussion of the 

 ■ papers read, and a series of questions was asked, these being subse- 

 quently replied to by each lecturer in turn. 



Mr. Ellis, of Taiping, next gave his experience of diseases. 

 He was of opinion that if they were going to ti'eat disease at all they 

 should do it thoroughlj^ by cleaning the whole place out and doing 

 away with the whole disease. It was of no use going only half way. 

 Some managers on seeing pink disease appear on their estates 

 naturally said it must have come from the kampongs, but it was just 

 as likely that the kampongs got it from the estates. (Laughter.) 

 Besides that there was the jungle that was a source of infection. 

 When trees wei-e seven or eight years old they were less liable to 

 infection than when they were younger. It was a great mistake to 

 take off a pest gang when the disease was less virulent, and the gang 

 sliould be kept on always. He refei-red to bark canker and other 

 diseases that came within his expei'ience, and gave the results of 

 treatment he had applied. He thought the black patch disease was 

 carried by the tapping knife and advised the disinfection of the 

 knife with a solution of 5 per cent, of formalin. The painting 

 with 20 per cent, solution of Izal in black stripe disease was good 

 in same cases, but the point was to let in air and light, good 

 drainage, reasonable thinning out, and then painting with some 

 disinfecting substance. 



Mr. Jarvis said that Mr. Belgrave had advised clean clearing 

 before planting but had not made it clear whether he advised timber 

 to be cleared from old estates. 



