XIII, A, 4 Reinking: Philippine Economic-Plant Diseases 



191 



often penetrates farther than can be seen with the naked eye. 

 All large wounds should be painted with a creosote paint or 

 white lead. Severely infected trees should be cut down and 

 burned immediately. 



SCALY BARK 



Symptoms. — A disease characterized by a scaling of the bark 

 is common, but the causal factors have not been determined. 

 The attacks of an insect just below the bark cause a sloughing, 

 but this does not appear to be the only factor. 

 SOOTY mold: meliola 



Symptoms. — Frequently this sooty mold is found growing over 

 leaves, stems, and fruit. It is 

 superficial, growing on the sug- 

 ary exudate of aphids. The 

 fungus has been observed on 

 Citrus medica Linn., Citrus no- 

 bilis Lour, and on Citrus maxima 

 (Burm.) Merr. (Citrus decuma- 

 na Linn.) and undoubtedly oc- 

 curs on other Citrus species. 



Causal organism. — A dense 

 mass of brown mycelium, with 

 its characteristic hyphopodia, is 

 produced over the affected area. 

 Setae and dark brown spherical 

 perithecia are produced from 

 the mycelium (fig. 9). Within 

 the perithecia are found the 

 hyaline globular asci with from 

 two to four typical, five-celled 

 brown ascospores (fig. 9). 



Control. — The disease may be controlled by spraying with 

 lime-sulphur, which will keep the aphids under control as well 

 as destroy the fungus. 



SPINY mold: imperfect fungus 



Symptoms. — A spiny mold niay be produced on leaves, stems, 

 and fruit. Black tufted masses of fungus appear in spots or 

 frequently in masses, covering the entire affected portions. The 

 fungus grows primarily on the exudate from aphids. 



Causal organism. — A dense mass of brown mycelium, with 

 numerous setae, is produced. The setse are septate and much 

 elongated and they give the tufted appearance. Hyaline, elong- 



Meliola, on Citrus nobUis Lour, 

 o, perithecium (X 75) ; 6, ascus 

 (X 310) ; c, ascospores (X 310) ; 

 d, mycelium with hyphopodia 

 (X 310) : e. setse (X 75). 



