626 



Journal of Agriculture, Victoria. 1 15 Oct., 1919. 



DISEASES OF PLANTS NEW TO VICTORIA. 



B>/ C. C. Briftlebank, Vcf/efable Patholof/ist. 

 I. Anthracnose of Lettuce. 



Didymana perforans (Ell. et Ev.) Dand. 



Syn. Marssonia perforans (Ell. Ev.) 



This destructive disease was fii-st found on cultivated lettuce (Lactnca 

 sativa) and was recognised as a new disease by Prof. A. D. Selby, who 

 directed attention to it in Bulletin No. 73 of the Ohio (U.S.A.) Agri- 

 cultural Experiment Station. The name, Marssonia perforans, was 

 proposed by Dr. J. B. Ellis, to whom specimens had been sent by Prof. 



Plate 1.— Lettuce leaf show^ing injury caused by M. perforans 

 (Ell. et ev.) Dand. 



Selby. The following is the description of the fungus and the appear- 

 ance of the affected plants given by the discoverer: — -" Spots, small, 

 irregular in shape, 1-2 mm. in diameter, pale, soon deciduous. Acer- 

 vula 100-120 in diameter, or by confluence longer. Conidia abundant 

 clavate, or wedge shaped. Hyaline faintly uniseptate 11-15 by 2|-3 

 /J.. Exceptionally reaching 20 ;i long." The history of the entry of 

 this disease into Australia is like that of several -otlur plant diseases, 

 and clearly shows the danger attached to the unrestricted importation 

 of seed from various parts of the world where certain diseases are known 

 to exist. Owing to the war conditious lettuce seed could not be obtained 

 from the usual source, and consequently supplies were obtained from a 



