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 Ustulina, those should be destroyed as soon 
as they appear. Rubber stumps left after thinning out often bear a 
plentiful crop of Ustulina fruits — the practice of felling trees by 
severing the laterals has mucli 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 disea n, it should be borne in mind that, given time, contact 
diseases spread at what may be called “ compound interest, 1 ’ 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 the mycologists of the Department 
that the measures outlined above will be found in every case to be 
abundantly justified. 
Discussion. 
The 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 treat disease at all they 
should do it thoroughly 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 were seven or eight years old they were less liable to 
infection than when they were younger. It was a great mistake to 
take oft a pest gang when the disease was less virulent, and the gang 
should be kept on always. He referred to bark canker and other 
diseases that came within his experience, 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, hut the point was to let in air and light, good 
drainage, reasonable thinning out, and then painting with some 
disinfecting substance. 
Mi*. 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. 
Bi-zW B.5 
