JO Aug., 19 1 2.] 



The Oliv 



469 



A small [lar.isitic fly is found to be attacking this scale, and lending a 

 hand towards its suppression. However, the grower must as vet ]f)ok to 

 other means of effectively combating it. 



The Sootv Mould F'ungus. — This fungus is known in many places as 

 {Meliola camel lice. Sacc). Some difference of o])inion exists as to whether 

 this is its right name. It does not appear to Ije definitely settled which of 

 the species of this fungus — if the\ are various — feeds on the honeydew of 

 the scale insects on different trees. It is verv probable, as pointed out by 

 Mr. McAlpine. that different species cause the trouble in different countries 

 and on difft-rent trees. The Black Blight {Capiiodium citricolum. McAlp. ) 

 which attacks citrus trees in this country, appears to live, like allied forms, 

 on the sugary secretions of aphides and scale insects. Hf)wever this may. 

 be, it will usually be found sufficient for the i)ur])ose of the horticulturist 

 to know that thr \arious forms of this fungus have a similar effect in 

 injuring the functions of the leaves, and that if the trees are ke[)t free from 

 the i)resencc^ of scales or aphides the fungus also ceases to exist. 



FIG. 24. — OLIVE TWIG ATTACKED BY RED SCALE (aSPIDIOTUS ROSSI). 



Trees attacked by the Black (31ive .Scale are usuallv easilv distinguished 

 by the dark appearance given them 1)\ the presence of the Sooty Mould 

 Fungus ; the lea\es also become shiny and sticky in cases where the attack 

 is severe. The chief injury caused by the fungus is the clogging up of 

 the .stomata of the leaves, antl in cases where there is a bad attack the 

 branches and lea\es become almost completely covered with an incrustation 

 cf this fungus, and, consquently. cannot properlv perform their functions. 



Treatment. — Since this disease derives its food supplies from the secre- 

 tions of aphides or scale insects, it is obvious that by destroying such 

 in.sects you also do away with the food supplies of the fungus ; and, as a 

 result, it .soon disappears. Hence the grower should direct his attention 

 firstly to the destruction of the scales. However, to hasten the removal 

 of the fungus a weak solution of some fungicide — such as Bordeaux 



