18 
(\\RXE — Broicn Hot of Citrus. 
■\veather Oosjxnut is very active producing’ a slimy wet rot. Under 
suck conditions it is not uncommon to see lenioiisi oii the trees become 
so soft that tliey elongate and eveiituany fall in a soft rotten mass. 
Tlie strong’ sour smell induced by Oospora frequently masks the 
cliaracteristic smell of Brown Rot. In other ’ways the disease de 
velops as on tlie orange. 
Affected leaves of lemons as well as oranges and mandarins 
develop (lark water-soaked areas usually at the tijis, but not infre- 
quently e.xtendbig in from the edges. Portion of the half margin 
is usually involved, though occasionally the disease may develop 
centmlly on a leaf. Aff‘ecte<l leaves curl somewhat and fall readily 
Avliile still green oven- the greater part of their surfaces. Leaf 
attack is usually the first indication of the presence of the disease 
and is sometimes the onlv form of the disease to develop. The 
]u-esence of the disease iji mild or earlv attacks is best seen by ob- 
serving The fallen leaves on the ground. Lower leaves are usually 
first infected but later thev may lie found at any level. On oranges 
and mandarins leaf dropping may go on. until more or less com- 
tdeto defoliation of paid of the tree may result. With the exception 
of a few cases of conqilete defoliation the affected portion involves 
almost entirely a strip running vertically from bottom to top. ex- 
tending laterally from two or three feet to the entire width of a 
tree (Plate T), These severe infections occur on the side of the 
trees most sheltered from the sun or from wind. Ju tlie majority of 
cases it is confiiuul to the Pastern and Southern side. On lemon 
trees the leaf infection is similar to that of the orange tree but is 
more general, and not confined to portions of the tree. In 1921 
a number of large lemon trees were seen at Ifaddington (Plate 1 1 
Avhich were conijiletely defoliated, the large crop of fruit remaining 
sound on the trees. 
Lcaif blight without fruit rot is not uncommon in mild cases 
with oranges. Heavy leaf infection is invariably associated with 
fruit infection. On lemons, however, as in the case already men- 
tioned. leaf iuf(‘ctioii may be plentiful without the fruit being 
attacked. 
The recognition of an unknown pathogen causing leaf blight 
was made by the writer before he realised that all cases of Bi-owti 
Kot Avere due to the saxie cause and not to Pytitiacystis ritroph^ 
thora (7) . 
TiriO BLIGHT. 
Accompanying severe leaf defoliation the smaller twigs and 
blanches are killed. As a consetjuence frnit bearing in the following 
season on the affected portion is largely or entirely ])revented. 
