PESTS OF OK CHARD AND FRUIT GARDEN. 



23 



American shot- hole fungus (Scptoria cerasina) occurs on Plum and 

 Cherry leaves, and has strongly curved conidia (50-75 fj long). 



Another shot-hole fungus (Cylindrosporium padi) having curved 

 filiform conidia (48-62 x 2 p) occurs also in the United States. 



An Australian shot-hole fungus (Phyllosticta prunicola) affects the 

 leaves of Apple, Plum, and Cherry in similar manner in Italy, and extends 

 to Australia (5x3 /*). 



The genuine Australian shot hole (Phyllosticta circumscissa), as it 

 claims to be, attacks Cherry and Peach leaves (8x2ju). 



Besides which a white mould (Ovularia circumscissa) is credited with 

 forming similar shot holes in Cherry leaves in Kussia (15-18 x 6-7 /u). 



And a black mould performs the same office (Cercospora circumscissa) 

 upon Plum leaves in the south of Europe, in the United States, and in 

 Australia (50 x 3^-4 jj, 3-4 septate). 



Still another shot-hole fungus, and one of the most common in 

 Australia, is a black mould (Clasterosporium carpophilum) on Peach, 

 Almond, Cherry, and Apricot (54 x 14 4-5 septate). This is known also 

 in Italy, Switzerland, Austria, and Portugal. 



Strange that none of these should yet have paid a visit to Britain. 



Mc Alpine Fung. Dis. p. 33. 



American Black Knot. 

 Plowrightia morbosa (Sacc). 



Although this is an American disease, unknown in Europe, it is the 

 worst enemy of the Plum and Cherry in the United States. It forms 

 black rough excrescences on the branches, often several inches in length. 

 At first the branch swells, which is followed by a longitudinal cracking 

 and gaping of the bark. Then the surface is covered with a dark olive 

 velvety coating of mould, which produce the conidia. 



Later on in the season the olive mould disappears, and a thick out- 

 growth of fungus mycelium succeeds, which produces a stroma, or bed for 

 the ensuing fungus. During the winter, cavities are formed in this 

 stroma, and these contain cylindrical sacs, or asci, closely packed together, 

 each enclosing eight sporidia, which are oblong, unequally two-celled 

 (16-20x8-10^). 



As it is confined to the United States we must leave with the 

 sufferers to adopt the best means at their disposal to exterminate the 

 pest. 



Farloiu, Bull. Buss. Inst. 1876, p. 440, plates ; Sacc. Syll. ii. 5295 ; 

 Mass. PI. Dis. p. 137, fig. 26. 



Peach Eot, or Anthracnose. 



Gloeosporium Iceticolor (Berk.), PI. XL fig. 20. 



This disease attacks the mature fruits and produces depressed spots 

 which are whitish in the centre with a blackened margin. The pustules 

 are circularly arranged towards the centre, and are rosy, seated beneath 

 the cuticle. The conidia, which are produced in the pustules, are oblong, 



