139 



4. Direct the spray so as to coat all the young fruits evenly, but 

 thinly. It is not necessary to spray the leaves, but it will not be possi- 

 ble to aviod wetting them when spraying the fruit. 



5. Watch for scale insects, and if they appear in great numbers use 

 resin wash, kerosene emulsion, or other insecticide. This caution is 

 necessary because in some cases where trees are sprayed with Bordeaux 

 mixture the fungous parasites of the scale are killed, and consequently 

 the scale insects multiply very fast. As yet no such effect has been 

 observed when ammoniacal copper carbonate was used, but the possible 

 dange«r from this source should be borne in mind 



6 If preferred, Bordeaux mixture can be used in place of the am- 

 moniacal solution of copper carbonate. In preparing the Bordeaux 

 mixture, take 6 pounds of copper sulphate and 3 pounds of lime ; add 

 25 gallons of water to each, then mix, and add 6 pounds of dissolved 

 soap to the mixture. This spray must be applied with care, giving 

 the trees only a thin coating, otherwise the youngest foliage may be 

 injured or scale insects induced. 



SOOTY MOULD. (^) 



Sooty mould of the orange, or smut,(^) as it is sometimes erroneously 

 called, is a malady which frequently causes serious damage. The 

 fungus producing it is of saprophytic habit, deriving its nourishment 

 from the sweet fluids (honey dew) secreted by certain insects, the 

 attacks of which it invariably follows. As the honey dew falls, it 

 strikes principally on the upper surfaces of the leaves and exposed 

 branches and upper portions of the fruit (the stem end, as the fruit 

 are pendulous), and it is on these portions that the sooty mould grows. 

 It develops also to some extent on the lower surfaces of the leaves, but 

 is not so abundant here. In Florida sooty mould follows principally the 

 attacks of the mealy wing or white fly {A ley r odes citri B. & H.), wax 

 scale {Ceroplmtes floridensis), mealy bug (Dactylopius citfi), orange 

 plant louse or aphis ( Aphis gossypii Glover), etc., and spreads, as these 

 insect pests spread. It is only where it follows the mealy wing, how- 

 ever that it becomes serious. In this State it is estimated that the loss 

 it causes is not far short of ^50,000 annually. 



Besides occurring on all varieties of citrus fruits, sooty mould is fre- 

 quently found on a number of wild plants in Florida. It is particular- 

 ly abundant on the gall h^TYjillex glabra), red bay, {Persea carolinen- 

 sis), and magnolia. On the gall berry it follows attacks of the wax 

 scale {Ceroplaates floridensis), which also infests the orange. 



Sooty mould is probably common in aU orange countries of the world. 

 In California it causes much damage and is considered a serious malady. 



(1) Sooty mould of the orange is probably produced by several different species 

 of the genus Meliola. The forms known as Meliola penzigi and Meliola camelioe 

 appear to be the most common in Florida. In publications in this country the 

 fungus has usually been referred to Gapnodium citri and Fumago salicina. The 

 disease is known in Italy under the names fumaggine, morfea, nero, etc., and in 

 Germany as Russthan. 



(2) Smut is the name very generally applied to diseases produced by the true 

 smut fungi {Ustilaginece). 



