Cakne — Brou')i Jlot of Citrus. 
17 
to tlio disease lias not been observed. Late varieties of oran^'^s 
stiff er less from tlie fruit rot than tlie early ones, itandarins am 
])articularly stdtjeet to both leaf and fruit infection. Lemons 
a]']'e;(r to l)e less sultject to fruit rot and to be more susceptible 
to leaf infection. 
SYMPTOMS OF BROWN ROT IN WESTERN AUSTRALIA. 
The syni])toms of Lronn Kot in Western Australia Avere des- 
erilu'd by tlie writer in 1924 (fi). Affected oranges and mandarin 
fruits develoji a dull dark broAvu area, usually on one side, which 
sjireads until the Avliole fruit may be involved. The rot is not a 
soft one, and is accomj)anied by a very penetrating and easily re- 
i-og-nisalde odour, quite distinct from those usually associated Avith 
rottin.g and monldy eitrus fruit. When free or relatively so from 
seeondary infections the affected aiams beconu' dark^ dry. and cveu' 
tuallv sunken. The Avhole fruit eA'entually shrinks to a dry hard 
mummy. Lnder normal conditions in the orchards, however, second- 
ai'y infections closelA' folloAA' BroAvn Kot in the A'ast majoiity of 
fruit. Tlie principal secondary organisms observed have been 
r(f)icitUum dipitaium, Hacc., 7\ itaHcum Wehn, P. spp., CoUeto^- 
trirh u m plocosjtoroidrs Penz . , Ctadosponum hcrboru m ( Pers . ) 
Link., Fusarium sp., J^honut sp . ^ lihisopu.s sp . , Oospora citri-aiiraniu 
(Perr.) Sacc. & 8yd., and bacteria, the first four and bacteri.a 
predominating . 
During Avet conditions in the orchard or Avhen placed under 
a bell-jar a fine short groAvth of Avhite mycelium develops on and 
around the lesions. 
Apparently-sound fruits in contact Avith affected fruits are al- 
most invariably affected also. Varieties Avhich. like the common 
orange, carry their fruit in bunches are in consequence liable to 
heavy infection. The first fruits affected are usually near to or in 
contact Avith the soil, but once the disease* has become Avell evident 
in an orchard, affected fruits may be found at any height on the 
trees even at the A’ery top. 
Affected paids of lemon fruits develop a straAV colour showing 
in contrast against the brighter yellow of tlie sound skin. The skin 
ajipears to be distended making it smooth and someAvhat glossy in 
contrast to the rougher surface of the sound fruit. The affected 
areas eventually turn broAvn. As Avitli oranges in the absence of 
secondary contamination affected fruits shrink and dry. This is. 
hoAvever, rare Avith lemons OAving to secondary infection by tin- 
oi'gauisms Avliich attack oranges Avith the difference that Oo.sporo 
ciiri-aurau tii predominates even OA'er PeniciUium spp. During AAmt 
