. Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . FIG, 6. SURFACE OF POTATO LEAF GREATLY MAGNIFIED, SHOWINGGERMINATING SPORE ENTERING BREATHING PORE AT a,AND GOING THROUGH EPIDERMIS AT C. developed to a considerable extent they collectively formthe mycelinm of the fungus. After the Peronospora plant has reached this stagein its existence it is ready to prepare for sends out through the breathing pores of the leafbranching threads, and on these develops the conidia, asalready described. By
. Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . FIG, 6. SURFACE OF POTATO LEAF GREATLY MAGNIFIED, SHOWINGGERMINATING SPORE ENTERING BREATHING PORE AT a,AND GOING THROUGH EPIDERMIS AT C. developed to a considerable extent they collectively formthe mycelinm of the fungus. After the Peronospora plant has reached this stagein its existence it is ready to prepare for sends out through the breathing pores of the leafbranching threads, and on these develops the conidia, asalready described. By means of these conidia, which are produced ingreat abundance, and the swarm-spores originating from. 10 rUXGI AND FUXGICIDES them, the fungus is able to multiply with marvelousrapidity during the warm, damp weather most favor-able to its growth. In an ordinary potato field theabundant foliage, wet with rain and full of juicessuch as would favor the growth of the mycelium, isswayed by the wind, and leaf flaps upon leaf over thewhole area; quite apart from the wind-blown conidia, the active zoospores cansoon spread from any onecenter, and at once infectnew leaves. In a fewhours fiesh disease-spotsare developed, each put-ting forth new crops ofFIG. 7. sECTTox OF TLEAF sHowryG couldla, whlch again ger-MYCELiuM OF FUNGUS, ^lAGxiFiED. niinatc aud send out zoo-spores, and so on. Under these conditions it is easyto see that the attack may be sudden and destructive. Besides these conidia, or summer spores, many par-asitic fungi develop in autumn certain spores, by meansof which the fungus passes through the winter. Thelatter are usually better protected than the are sometimes cal
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
