FUNGI IMPERFECT! 



337 



be seen, therefore, that many symptoms of the disease as described 

 in California are more or less identical with Clasterosporium car- 

 pophilum (Lev.) Aderh., as described by McAlpine 1 in Australia. 

 It also occurs in Algeria. 2 According to Smith, the fungus could 

 not be mistaken for a simple hyphomycete, as shown by the ag- 

 gregate conidiophore production (Fig. 160). The conidial stage 

 of the fungus is produced both on leaves and shoots, the pustules 

 appearing at the center of the spots. The)' are, however, not 

 readily observed, since the spots on young shoots are often sterile 

 and those upon the leaves may 

 fall out before the production of 

 spores. Perhaps the most unfortu- 

 nate phase of this disease is kill- 

 ing of winter buds, which of course 

 greatly destroys the vitality with 

 respect to fruit production the fol- 

 lowing season. It is quite probable 

 that this fungus is the same as 

 Helminthosporiiim carpophilum 

 (Lev.), and this is also the view 

 of McAlpine. 



Control. In controlling this dis- 

 ease, it has become evident that 

 winter spraying is essential. The 

 disease is reported to make its 

 appearance early in January in Cal- 

 ifornia, and generally somewhat prior to the activity of the winter 

 buds. The spraying which may be given for. prevention of leaf 

 curl is ordinarily too late for the best results upon this blight fungus. 

 It is recommended, therefore, that an additional spraying in Cali- 

 fornia be given in November or December to assist in controlling 

 this blight organism. If a single spraying only can be given, it is 

 perhaps best to give it in December, but later than early January 

 under California conditions is ineffective. 



Fig. 160. Coryneum Beijerinckii 

 (After R. E. Smith) 



1 McAlpine, D. Fungous Diseases of the Stone Fruits in Australia, and Their 

 Treatment. 1902. 



2 Trabut, L. Le Coryneum. Maladies des arbres a noyaux. Built agr. de 

 l'Alge>ie et de la Tunisie 10 : 1904. 



