392 DISEASES OF CULTIVATED PLANTS 



Tea leaf felt. Bernard describes an injury caused to the 

 leaves of Thea assamica in Java by an undescribed species of 

 fungus, which he names Hypochnus theae. It forms a thin 

 reddish-white weft or hymenium on the young twigs and on 

 the under side of the living leaves. The fungus is not a 

 .parasite, but when it occurs in quantity the stomata are 

 stopped up, causing the shoots to dry up, and the leaves 

 to fall. 



Basidia 20-25 x 6-8 ft, sterigmata 4, 6-8 /x long; spores 

 hyaline, smooth, 7-9 X 5-7 p. 



It is recommended that diseased shoots be removed and 

 burned, and the bushes sprayed with Bordeaux mixture. 



Bernard, Ch., Bull. Departm. Agric. aux Indes Neerland, 

 No. 6, p. 55 (1907). 



Leaf blight. Apple, pear, quince, plum, and other orchard 

 fruits have suffered to a serious extent in Brazil and the United 

 States from the presence of Hypochnus ochroleucus (Noack). 

 During the early stage of the disease the symptoms resemble 

 those due to ' fire blight,' caused by Bacillus amylovorus (De 

 Toni), that is the leaves on numerous shoots are dead. In 

 'fire blight,' however, the dead leaves usually stand erect, 

 whereas in the present instance they hang down in clusters. 

 The injury caused by leaf blight is further confined to the 

 leaves, the twigs not dying as in the bacterial disease. At a 

 later stage the leaves fall away, leaving the shoots naked. 

 Careful examination of a tree attacked by leaf blight reveals 

 the presence of roundish sclerotia on the branches, 3-4 mm. 

 in diameter, whitish at first then chestnut brown in colour. 

 These are formed in abundance on the shoots of the year, 

 especially on the lower shaded side, but occur sparingly or 

 not at all on the petioles and leaves. Sclerotia are rarely 

 found upon the fruit. In addition mycelial ribbons or 

 rhizomorphs extend lengthwise along the twigs and petioles. 

 These structures usually remain unbranched between the 

 nodes, though they sometimes branch, the branches often 

 anastomosing to form a network. On the blade of the leaf 

 the bands of mycelium open out to form a more or less dense 

 network of mycelial threads, which often run out so fine as to 

 be invisible to the naked eye. 



These rhizomorphs are white at first, gradually changing to 

 a glistening brown colour. In some instances a compact 

 hymenial layer is formed on the under surface of the leaves ; 



