FLORIDA STATE HORTICULTURAL SOCIETY 
121 
spray should be some time in the latter 
part of April, again in June, and possibly 
in October. The sulphur sprays are the 
most effective in its control, the oil sprays 
have considerable effect in control, but 
are in no sense equal to the sulphur sprays. 
A theory has been advanced that the 
mite multiplies in the soil, as well as on 
the tree. This theory is based on the fact 
that trees on land which is frequently 
worked have darker fruit than trees on 
land infrequently cultivated; as trees on 
lawns, etc. It is claimed that the stirring 
of the ground brings the mites to the sur¬ 
face and affords a chance for them to 
4 
travel to, and on to, the trees. It is an 
established fact that the mite is capable 
of traveling considerable distances in a 
few hours. The theory at least opens a 
field for some experimental work. 
Another fact worth mentioning is that 
of the effect of the oil and sulphur sprays. 
Even if the oil sprays are used in a suffi¬ 
ciently concentrated form to kill all mites, 
the fruit is nevertheless darker than where 
sulphur sprays are used. The reason for 
this may be the action of a secondary 
agent, that of a fungus. If this be true, 
sulphur sprays having a fungicidal action 
destroy the fungus as well as the mite, 
therefore leaving the fruit brighter than 
the oil sprays which possess no such prop¬ 
erty. 
Thrips are often blamed for the irregu¬ 
lar, silvery colored markings found on cit¬ 
rus fruits. It is doubtful, however, if this 
can be definitely proved. 
Of the several fungi causing the russet- 
ing of fruit, the most important is prob¬ 
ably melanose. This fungus develops 
most rapidly when the weather conditions 
are warm and moist. Melanose causes 
reddish brown spots, which, scattered over 
the fruit, give it a most unple&sing appear¬ 
ance, and for this reason prevents its ready 
sale. The fungus develops in the dead 
wood. If this is kept pruned out and the 
trees sprayed with sulphur compound just 
after the blossoms fall, and again in from 
four to six weeks, the grower will have 
very little trouble from fruit being dis¬ 
colored with melanose. The methods 
used for the eradication of melanose also 
serve to prevent stem end rot. It has 
been conclusively proved that this rot is 
caused by the same fungus as that causing 
melanose, so that anything tending to 
eradicate melanose, will to the same ex¬ 
tent prevent the development of stem end 
rot. 
The russeting resulting from the with- 
er-tip fungus is quite characteristic and 
is known as tear-streaking. It is a de¬ 
batable subject, if spraying with fungi¬ 
cides is advisable. Pruning out dead 
wood and proper fertilization are the best 
methods of control. Anthracnose, anoth¬ 
er form of the wither-tip fungus, causes 
considerable loss from dropped fruit and 
spotting of fruit after it is picked. Any 
methods of control used for wither-tip also 
proportionately lessen losses from anthrac¬ 
nose. 
Citrus scab, also known as lemon scab, 
is caused by a small parasitic fungus. It 
produces dark brown, corky projections, 
which make every affected fruit a cull. 
Pruning out all affected' growth and spray¬ 
ing with sulphur solution shortly after 
growth starts are the most approved pre¬ 
ventive methods. 
Scaly bark or nail head rust is also 
