which secrete " honey-dew." Injury is done to the trees 

 by preventing the leaves from performing their proper 

 functions, and fruit covered by the fungus is frequently 

 rendered unsaleable. The black incrustations occur where- 

 ever the orange is cultivated, and are caused by different 

 species of the genus Meliola in different countries. 



Messrs. Swingle and Webber have demonstrated that 

 resin-wash is effective, since it destroys the " honey-dew " 

 secreting insects. It is important that the spraying should 

 be done when the insect is in the larval stage. Fumiga- 

 gation with hydrocyanic acid gas is also very effective ; 

 the treatment should last for about forty-five minutes, and 

 should be done when the temperature is low. 



Swingle and Webber: U.S. Dept. Agric, Div. of 

 V eg. Physiol, and Pathol., Bull. No. 8. 



MASSEE : Text-Book of Plant Diseases, p. ioo. 



DIMEROSPORIUM MANGIFERUM, Sacc. 

 ( = CAPNODIUM MANGIFERUM, C. & B.) 



(Black Blight of Mango.) 



This is a black, incrusting, non-parasitic fungus which 

 forms black patches on both sides of the leaves of mango. 

 The fungus spreads somewhat rapidly, and by forming a 

 coating over the leaves prevents them from carrying out 

 their assimilating functions. It is certain that the fungus 

 follows such insects as secrete " honey-dew." The method 

 of treatment is, therefore, similar to that recommended for 

 the sooty mould of orange (Meliola spp). 



Diagnosis : Mycelium incrusted, effuse, sometimes 

 almost covering the entire surface of the leaf, amphigenous, 

 velvety, intensely black ; perithecia globose-pyriform, 

 rounded at apex, mouth absent ; asci obovoid, rounded at 

 apex, 48-50 by 30 microns ; spores 8, hyaline, elliptical, 

 slightly constricted at the septum, 12-15 by 5-6 microns. 



MASSEE : Text Book Plant Dis., p. 103. 



Cooke & Broome : Grev., IV., p. 117, pi. 63. 



bPHAERIACE^E. 



TRICHOSPHAERIA SACCHARI, Masses. 



(Rind Fungus of Sugar Cane.) 



Attention was first called to the fungus in Trinidad in 

 the year 1893. At the end of the last century the disease 



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