FUNGOID PESTS OF CULTIVATED PLANTS. 139 



colourless, and at first growing from short sporophores, or pedicels 

 (40-50 x 4 /*). 



First observed in this country at Clevedon, and since then has been 

 found in several localities. At one time the theory was promulgated in 

 France that this disease of the leaves was the cause of " muscardine," or 

 silkworm disease, but for lack of evidence the theory soon gave way. 



Trees when once attacked continue to sutler year after year with 

 increasing energy. Cold weather appears to check it, but in warm 

 seasons it extends rapidly. 



The disease is known in France, Italy, Germany, Austria, and Russia. 



Sacc. Syll. iii. 3136 ; Grevillea, vi. p. 72, xiv. 104 ; Gard. Chron. 

 Nov. 1877. 



Mulberry-leaf Blight. 



Cercospora moricola (Cooke), PL XII. fig. 29. 



Nearly at the same time that the Mulberry spot appeared in this 

 country another disease was found affecting the leaves of the Mulberry 

 tree both in this country and in the United States. It belongs to a 

 genus of black moulds which are really very persistent in their attacks 

 and very troublesome to the cultivator, but not likely to be of so much 

 importance to us as to countries where the leaves are required in con- 

 nection with the silkworm industry. 



The spots occur on both surfaces, and are orbicular, of a reddish- 

 brown colour. Upon these spots are produced tufts, or bundles, of short 

 olive threads, which burst through the cuticle and produce at the apex 

 of each thread a long narrow spore, or conidium, which is three or four 

 septate, and narrowed towards one end (70 x3 //). 



No experiments have been made to control this disease, as in its 

 present development it cannot affect the production of fruit. 



Sacc. Syll. iv. 2281 ; Grevillea, xii. p. 30. 



Mulberry Black Mould. 

 Clasterosporium parasiticus (Cooke), PL XII. fig. 30. 



When tbe Mulberry-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. 



