SEPTORIA 425 



Care must be taken not to mistake Septorium tritici (Desm.) 

 with Septoria graminum (Desm.). 



Cavara, Zeitschr. Pflanzenkr., 3, p. 16 (1893). 

 Janczewski, Recherches sur le Cladosporium herbarum, etc., 

 Cracow (1896). 



Prillieux, Malad. des Plantes Agric^ 2, p. 301 (1897). 



Wheat node fungus (Septoria nodosum, Berks.) attacks 

 the nodes of wheat stems when the plant is about half grown, 

 and forms pale fawn-coloured patches, often bounded by a 

 darker line, and studded with the minute blackish perithecia, 

 spores minute. 



This parasite was first observed by Berkeley in 1845, who 

 states that it was very abundant in wheat fields, and did a 

 certain amount of injury. It has not been observed during 

 recent years. 



Celery and parsley leaf scorch. This disease, caused by 

 Septoria petroselini (Desmaz.), is often the cause of serious 

 loss unless promptly checked, as when it once appears, 

 it spreads along the rows of celery with great rapidity. It 

 usually appears when the celery is nearly ready for the 

 market. Small, scattered brown patches first appear on the 

 living leaves, these gradually increase in size until the entire 

 leaf is covered ; at this stage it turns brown and dies. If the 

 brown spots are examined with a pocket-lens, numerous 

 minute, jet-black spots are seen scattered over their surface. 

 These black spots are the fruits or perithecia of the fungus 

 containing the spores. 



Perithecia more or less flattened, with a minute pore, 

 180-250 /*. Spores filiform, often slightly curved, usually 

 3-septate, 50-65 x 1-5 /*. 



If detected early in the season, spray with dilute Bordeaux 

 mixture, or with potassium sulphide solution. Diseased 

 foliage should be buried. This disease, as the specific name 

 denotes, also attacks parsley. 



Black currant leaf spot (Septoria ribis, Desm.) forms 

 small brown then purplish spots on living leaves of the black- 

 currant. Conidia long and very narrow, hyaline, 50 /x 

 long. 



Horse-chestnut leaf spot (Septoria hippocaj^>. and 

 Br.) forms spots, at first minute and scattered, 



