PESTS OF ORCHARD AND FRUIT GARDEN. 



31 



Mulberry Black Mould. 

 Clasterosporium paras-it icum (Cooke), PL XII. fig. 30. 



When the Mnlberry-leaf spot was first found in this country it was 

 accompanied by another fungus of a very different character, which 

 appeared to be parasitic upon the same spots. Nearly every spot had its 

 centre blackened by some parasite, which it was ultimately found had no 

 relation whatever to the original disease. 



This fungus consisted of cylindrical spore masses with a short stem 

 and almost always obtuse apex divided by numerous septa, and con- 

 stricted at the joints so as to be torulose, or with a beaded appearance ; of 

 a clear brown colour when mature, and not unlike a caterpillar in 

 miniature. 



We have inserted this visitant here, not because we retain any 

 suspicion that it will prove to be a pest, but as a guide to its identification 

 should it accompany the leaf-spot again, and in order to secure more 

 definite assurance that it is only a saprophyte on the dead tissue of the 

 spots. 



Grevillea, vi. p. 74, with fig. 



Hazel-leaf Mildew. 

 Phyllactinia sujfulta (Sacc). 



Filberts being cultivated to a considerable extent as a table fruit, the 

 shrub will fall more naturally into position here than in the shrubbery. 

 The name by which the mildew was known for very many years was 

 Phyllactinia guttata, but it has since suffered in the lust for change. 



The under surface of the leaves is frequently covered with a delicate 

 white mildew consisting of a creeping interwoven mycelium of thin 

 threads with short erect branches bearing conidia. In the course of 

 time the little dark globose receptacles make their appearance, scattered 

 over the surface of the mildew. These little conceptacles are encircled 

 by a ring of spine-like, pointed, divergent appendages with a swollen base, 

 which stand around and guard the receptacles. 



Each receptacle encloses from four to twenty hyaline pouches, or asci, 

 which contain the sporidia, of which there are usually two, sometimes 

 three or four in each ascus (40-50 x 22-25 //). 



This is one of the superficial fungi to which it is believed that the 

 application of sulphur is beneficial, as in the case of the Hop mildew. 



Sacc. Syll. i. No. 13 ; Mass. PI. Dis. 98, 361, fig. 16 ; Cooke M. F. xi. 

 figs. 219, 220 ; Cooke Hdbk. No. 1912 ; Tubeuf, Dis. 179, fig. 



Hazel-leaf Spot. 

 Septoria avellance (B. & Br.). 



This leaf- spot was recorded by Berkeley, but does not appear to be of 

 very common occurrence. The receptacles are found on the under 

 surface of the dry and bleached parts of the leaves, but the sporules are 



