47 
Symptoms. —Wither-tip or brownish-black scab. 
(а) Leaf symptoms .—On the under surface of the leaf, brownish 
to fawn-coloured or whitish-grey blister-like patches arise, usually 
running along the veins. Several of these gradually coalesce, and 
form large irregular blotches, and ultimately the tissue of the 
leaf is destroyed, leaving only the thin, membranaceous upper 
epidermis. This, too, soon becomes ruptured and torn, and round 
or irregular-shaped holes occur in leaf. When appearing near 
the tip, it causes it to wither, and the leaf is often gradually 
destroyed from the tip downwards. When the tissue is disor¬ 
ganized, various saprophytic fungi may appear to hasten and 
complete the decay. (Plate VIII., Figs. 1 and 2.) 
(б) Stem symptoms. —Irregular, raised, firm, discoloured blotches 
occur on the twigs, usually of a dirty-grey colour, and con¬ 
spicuous on the still green bark. (Plate VII., Fig 1.) These 
blotches may either be isolated with slightly raised dark margins, 
or continuous in long lines, and studded with the minute dark 
pustules. The spotted dead brown portion of the twig becomes 
sharply marked off from the still living and green portion by a 
raised ridge round the twig, where the sunken dead tissue adjoins 
the still living tissue. If the shoots die from the tip downwards, 
and the greyish blotches show the minute black pustules 
(Plate VII., Fig. 2), there is every probability of its being this 
disease. 
(c) Fruit symptoms . — The fruit is largely covered, usually on one 
side, with numerous brownish to blackish scabby patches, fre¬ 
quently run together, and cracking up into numerous small areas, 
from which thin flakes are constantly being detached. It has 
been already noticed in connexion with fruit-scabbing. (Plate 
VIII., Fig.‘l.) 
Conditions favouring disease . — I have always found that the 
trees attacked were in a languishing condition, and had their 
vitality impaired from other causes, probably from an insufficient 
supply of water at the proper time. This disease may attack 
insufficiently nourished trees even in a dry season, but, under 
similar climatic conditions, I have not met with it in well-irrigated 
groves. 
Cause .—It is caused by a species of Phoma , but, like many 
other fungi, this one has different stages, so unlike each other 
that they have often received different names. 
If one of the greyish or fawn-coloured blisters on the under 
surface of the leaf is examined, it is found that the filaments of 
a fungus ramify beneath the epidermis, and the tissue may still 
be green. 
