150 



Journal of A(jiici(ltu.re, Victoria. [10 Makcu, 1919. 



districts of Victoria best suited for apple culture are also the most 

 favorable for the growth of black spot. Prior to the more general use 

 of Bordeaux mixture, copper-soda, and lime-sulphur, the damage caused 

 to fruit, as well as the losses which resulted from the injury done by 

 black spot to the foliage were enormous. Since the growers have more 

 extensively practised spraying with fungicides, however, losses from 

 these causes have been very considerably reduced. 



It is now generally recognised that two forms of spores are involved 

 in the perpetuation of black spot — the conidial form produced during 

 the fusicladium stage on the surface of the leaf or fruit on spore-bearers 

 which pass through the epidermis during the vegetative period, and the 

 ascospores, the perfect form, which are contained in sacs or asci and 

 protected by a case or perithecium in the old leaf in the soil during 

 winter. 



Plate 189. 



Fig. 1. Rome Beauty leaf suffering from early infection. Fig. 2. An old Jonathan 



leaf carrying winter spores of black spot. 



That the fruit is liable to be attacked at any time during its deve- 

 lopment when the weather conditions favour the growth of black spot is 

 illustrated by the reproduced photographs in Plate 188, which depict three 

 stages of the affected fruit. The leaves also may become spotted at any 

 time under similar conditions. Fig. 1 shows four varieties of apples 

 about three weeks old; (a) is Anna Elizabeth, (&) London Pippin, (c) 

 Rome Beauty, and (d) Irish Peach. These four varieties do not appear 

 in the full-bloom stage at the same time, and specimens fairly uniform 

 in age and size were desired for illustration. Therefore Anna Elizabeth 

 and Irish Peach, produced from late blooms, were selected with London 

 Pippin and Rome Beauty from early flowers of these varieties. It will 

 be observed that the little apples are badly attacked with the spot, and 

 that the Irish Peach has already commenced to crack. The condition 

 of the fruit, as shown ^at this stage, is known as " early infection." The 

 London Pippin apple, in Fig. 2, was infected when it had almost 



