40 FUNGOID PESTS OF CULTIVATED PLANTS. 



experiments have been made with fungicides, which would probably be of 

 some service should the rust ever prove troublesome. 



Sacc. Syll vii. 2114 ; Cooke M. F. 215, f. 174, 175 ; Plowr. Brit. 

 Ured. 243. 



Leaf-spots, such as Septoria Hyperici and Ascochyta Hyperici, are 

 at present confined to the small uncultivated species of Hypericum. 



PELARGONIUM STEM-ROT. 

 Fusarium Pelargonii (Cooke), PL III. fig. 45. 



The disease attacks the stems of cultivated Pelargoniums, and at first 

 the varieties ' Vesuvius ' and ' Henry Jacoby,' and was first observed in 

 1896. 



The plant seems to stop growing, and in a few days some of the 

 lower leaves turn yellow, then the stem appears to turn black and 

 decay. 



The blackened stems exhibit over the decayed spots pallid, mealy - 

 looking little patches, not more than a line in diameter, sometimes with 

 a tinge of flesh colour. They seem to burst through the cuticle, and at 

 first are somewhat gelatinous, soon becoming dry and powdery. This 

 exudation consists of long spindle-shaped conidia, curved at each end 

 and attenuated to a point (60-70 x 6 /u), at first with three, and after- 

 wards five, transverse divisions, or septa, and uncoloured. 



As a recent disease the result of treatment by fungicides has not 

 been ascertained, but as it seems to be an endophyte, which establishes 

 itself in the tissues before it produces any external effects, it would be 

 better to prevent its spreading by burning all the diseased plants and 

 cleaning the soil, but the free application of diluted Bordeaux mixture 

 would prevent its spreading. 



Gard. Chron. July 25, 1896, p. 92. 



PELARGONIUM ANTHRACNOSE. 

 Glceosporium Pelargonii (C. and M.), PI. III. fig. 46. 



This is also a recently developed disease on the leaves of Pelar- 

 goniums, which was unknown until 1889, and has scarcely been observed 

 since. 



The leaves are attacked on the under surface, but do not exhibit any 

 distinct spots, only that the entire leaf soon droops and withers. 



Minute pustules are to be seen scattered over the surface, especially 

 in the neighbourhood of the veins, which cover the cells in which the 

 conidia, or sporules, are generated, from which when mature they are 

 expelled through a fissure in the epidermis. These conidia are quite 

 colourless, oblong, rounded at the ends (20 x 4-5 p), and a little 

 narrowed towards one extremity. 



All known species of Anthracnose are tenacious and dangerous pests. 

 Spraying with diluted Bordeaux mixture has been of some service. 



Sacc. Syll. x. 6764 ; Grevillea, xviii. 1889, p. 20. 



A supposed bacterial disease causes spots on Pelargonium leaves in 

 America. (See JOURN. R.H.S. xxvi. 1901, p. 550.) 



