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2 MULBERRY DISEASE. 
The parasite attacks the smaller branches, usually near the 
base. It is rare on those over an inch in diameter and is localized, 
extending only from one to three inches along the branch. At 
first it is usually confined to one side, but it always eventually 
affects the whole circumference of the attacked portion. Externally 
it is visible by the bursting out of a number of hard black cushions 
of fungus tissue, through angular cracks in the bark (Plate I, 
fic. 1). The whole of the affected area is slightly depressed and 
darker than healthy portions of the branch. ‘The branch is killed 
above the attack, but internal spread backwards to healthy parts 
of the tree does not occur. The disease is thus truly local, 
attacking and killing individual branches only ; where the attacks 
are multiplied, the whole tree naturally suffers through insufficient 
nourishment. Some old trees were seen, much stunted, covered 
with dead branches, and bearing leaf only on feeble shoots arising 
directly from the trunk or older wood ; it is possible that these 
may be eventually killed, but no case where death resulted was 
seen. In the young nursery stock the attack may occur on the 
main stem near the ground level. In the outbreak of 1906, 
seedlings of the second and subsequent years were attacked and 
had to be cut back right to the ground in many cases. They 
then for the most part threw up healthy shoots from below. The 
young tree in the foreground of the photograph, reproduced in 
Plate I, fig. 2, was affected at the base of the leading shoot, just 
above a large pruned-off branch. This position near a cut branch 
or above a fork is very common and a possible explanation will 
be given below. Old trees are usually attacked in the young 
shoots of the current year’s growth, which arise immediately below 
branches broken off during the silk-worm rearing season in April. 
The fungus is not confined to living mulberry trees, but is 
also found on dead prunings and broken off branches on the 
ground. On these it may cover the whole of the branch, instead 
of a small part, as on living trees. It would thus appear to grow 
more freely within dead than within living tissues. Many para- 
sites have this character, but are none the less destructive to living 
plants when they come into contact with them. 
