PESTS OF THE FLOWER GARDEN. 



35 



It should be vigorously attacked wherever it makes its appearance, and 

 infected plants destroyed. 



Sacc. SylL iv. 2311 ; Gard. Chron. August 21, 1886, fig. 50, and 1870, 

 p. 382 ; Mass. PL Dis. p. 320, fig. 87 ; Cooke Hdbk., 1728 ; Cooke Journ. 

 Q.M.C. 1877 ; Grevillea, v. p. 123 ; Tubeuf. Dis. 5, 6. 



The small white mould (Ramularia lychnicola) has only been seen on 

 Wild Lychnis. (Journ, R.H.S. 1902, p. 650, PI. II., f. 10.) 



Carnation Macro spore. 

 Macrosporium nob He (Vize.), PI. II., fig. 38. 



At first we were doubtful whether a species of this genus of black 

 moulds could become parasitic, since, for the most part, the numerous 

 species are saprophytes on dead and rotting vegetable matter. This is, 

 however, only one of three or four species which are now known to be 

 dangerous parasites. 



This pest usually forms small black spots on the leaves and stems, 

 which are sometimes confluent in patches. The mycelium is widely 

 diffused in the tissues before the spots appear. The clusters of threads 

 and conidia burst through the cuticle and are ultimately scattered. The 

 conidia are large, and pale olive-brown, subcylindrical, pear-shaped, 

 obclavate, or irregular (60-80 x 40 y). divided transversely, according to 

 the length of the spore, from four to ten times, each division again sub- 

 divided by longitudinal partitions into somewhat cubical cells, in a 

 muriform manner. Each cell capable of germination. 



It is also affirmed of this species that later in the season numerous 

 minute black sclerotia are embedded in the diseased parts. As these 

 would act as resting spores, to reproduce the disease in the following 

 spring, it is essential that every portion of diseased plants should be 

 effectively destroyed. 



Spraying with a solution of ammoniacal copper carbonate or potassium 

 sulphate arrests the spread of disease. 



Mass. PL Dis. 322, fig. 88, p. 440 ; Journ. R.H.S. 1902, p. 651, PI. I., 

 f. 8 ; Grevillea, v., p. 119. 



The rot-mould (Peronospora Dianthi) has not yet been found in this 

 country. (See Journ, R.H.S. 1902, PI. I., f. 7.) 



Bacteriosis of Carnations. 

 Bacterium Dianthi (Ar. & B.) PI. II. fig. 40. 



Examples of mysterious and inexplicable diseases of Carnations are 

 occasionally being investigated, some of which may possibly be attributed 

 to this disease, but until quite recently no other evidence beyond suspicion 

 has been afforded. 



In 1896 the results of investigations into the Bacteriosis of Carnations 

 in North America were first published, and from those we learn that the 

 disease is one of the leaf, rarely attacking the stem. In young leaves, 



D 2 



