Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . f pecidium sta^e; 6, same ofraspberry leaf showing both secidium and Puccinia spots. spring, aifected leaves having a peculiar golden color,which at once distinguishes them. A little later thesurface becomes more or less covered with small roundpatches of orange-colored spores, to which the commonname is due. The life-history of the fungus has onlyrecently been definitely worked out. The fungus exists on the blackberry plant in twovery different stages. The
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . f pecidium sta^e; 6, same ofraspberry leaf showing both secidium and Puccinia spots. spring, aifected leaves having a peculiar golden color,which at once distinguishes them. A little later thesurface becomes more or less covered with small roundpatches of orange-colored spores, to which the commonname is due. The life-history of the fungus has onlyrecently been definitely worked out. The fungus exists on the blackberry plant in twovery different stages. The orange spores that are devel-oped in spring and early summer, as shown in Fig. 48,belong to the CBcidium stage. They germinate on the 102 FUNGI AND rUNGICIDES leaves of raspberry and blackberry; the germinatingtubes enter the stomata, or breathing pores, of the leaf,develop a mycelium inside, and finally produce on thesurface the sj^ores of the teleuto stage, which has here-tofore been considered an entirely different fungus,called by botanists Puccinia loechiana. These Pucciniaspores are believed to be washed on to the underground. FIG. 48. SECTIOX OF BLACKBERRY LEAF, SHOWLVG DEVELOPMENT OPORANGE RUST SPORES. 3IAGNIFIED. shoots, and to infect them with the mvcelium, whichsubsequently produces the orange spores of spring. Blackberries are most commonly affected by thisfungus—especially certain varieties—but blackcap rasp-berries often suffer also. Treatment.—All diseased canes should be cut outand burned as soon as they show signs of disease, leavingnone to develop spores to infect other j^lants. In con-sidering varieties, select—other things being equal—thoseleast liable to the disease. Insist on your neighborskeeping the rust in check, and also look out for wildplants that have it. A spraying with fungicides will ORAI^GE RUST OF BLACKBERRIES 103 doubtless assist in preventing infection, especially of the Puccinia stage. An extended account of this disease, by Mr. G
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
