AT Ee 
indicated by the appearance of vertical black lines just above the tapping 
cut. These black lines, very thin at first, soon become larger and fuse 
with the neighbouring ones. The whole of the renewing bark can be 
decaying in this way. Occasionally transition stages between this form of 
canker and the ordinary canker patches zere found. The spreading of the 
disease was exceptionally fast; the use of water on the tapping cuts must 
have been the cause. The damage was serious; out of 10000 8 years old 
trees 6000 were so seriously diseased, that tapping had to be stopped. - 
The preventive-measures were the same as against the other forms of 
canker; besides the use of water on the tapping cuts was stopped. 
The only curative measure was the application of Carbolineum Plan- 
tarium diluted with water (lt was used at a concentration of 50°/, at first; 
now 20°% is used, and probably a lower percentage, say 5°/, would do as well). 
IL. A series of infection experiments brings conclusive proof 
that both cankerpatches and stripe-canker are caused by Phytophthora 
Faberi MAUBL. 
Cankerpatches could be obtained artificially by putting some mycelium 
into an incíision in the old bark, stripe-canker by bringing a suspension 
of conidia in water on the newly opened tapping-cut. Controls were made 
with clean water. 
In order to obtain cankerpafches six infection experiments with a 
total of 84 infections have been made; 56 were successful. Of the infections 
made in the rainy season and protected against drying out, 100°/, were 
successful; the control cuts remained always free of infections. One of the 
successful ínfections is reproduced on plate |. 
As to síripe-canker, five experiments with a total of 76 infections have 
been made to prove definitely, that this form of canker is caused by Phy- 
topthora as well; altogether 61 have been successful, the remaining ones 
being exposed to sunshine (in one case) or being made on tapping cuts 
that had not been opened for several days (in 14 cases). Provided 
the tapping cuts were opened daily and were not exposed to sunshine the 
infections were successful without a single exception. The control cuts 
remained free of infection. Two of these successful infections are to be 
seen on plate Il and III. 
Quotations of PETCH and BANCROFT (vide p. 6) prove, that stripe-canker 
is recorded from Ceylon and F. M. S. as well. PETCH says the phenomenon 
is probable due to excessive moisture. The abovementioned experiments 
not only show that Phytopthora is the real cause, but besides the controls, 
where pure water was used, prove, that excessive moisture alone is not 
sufficient to cause the decay of the renewing bark. 
Il. The progress of the disease was studied in detail on 33 cankered 
eren TPE 
