A physiological study of two strains of Fusarium in their casual relation to tuber rot and wilt of potato .. . ing and rolling on the margins of theleaves, the folding being most pronounced in the tips of the plants affected least showed discoloration on the margins,which at times was of a yellowish tint, at times purphsh to leaves of plants most severely affected showed a yellowing andburning of the leaf margins. One plant, inoculated with F. oxyspo-?rum, developed a pronounced rosette, but overcame this later, grow-ing into quite a normal plant (figs. 4 and 5). These sy
A physiological study of two strains of Fusarium in their casual relation to tuber rot and wilt of potato .. . ing and rolling on the margins of theleaves, the folding being most pronounced in the tips of the plants affected least showed discoloration on the margins,which at times was of a yellowish tint, at times purphsh to leaves of plants most severely affected showed a yellowing andburning of the leaf margins. One plant, inoculated with F. oxyspo-?rum, developed a pronounced rosette, but overcame this later, grow-ing into quite a normal plant (figs. 4 and 5). These symptomsremind one forcibly of certain symptoms of the leaf-roll disease whichhas received so much attention, and which has been made the subject l82 BOTANICAL GAZETTE [SEPTEMBER of thorough study by Appel and his co-workers (2, 4). Eventuallythe plants infected with F. trichothecioides showed much severers>Tiiptoms than those inoculated with F. oxysporum (fig. 6). Eightplants died in the former sets, and 3 in the latter. Plants infected\\dth F. trichothecioides showed such severe and rapid burning and. k^..i£^l Fig. 4.—Leaf roll and roselte ot field plant of the Pearl variety; August 1912,at the Substation at Mitchell, Neb. drying up of leaves, that the typical wilting phenomena werescarcely realized. The vascular bundles were blackened and theblackening extended even into the petiole and the leaf veins. Thisrapid kilUng was at first strictly localized on that side of the plantto which the inoculum had been applied, even in the leaf, where theleaflets on one side of the midrib would be affected, and those on theother side not. Eventuallv in those cases in which killing of the I9i6] LINK—FUSARIUM 183 whole plant took place, the fungus girdled the whole stem, whileplants that were not girdled lived on, even though one sidewas entirely destroyed. There was little lateral and subsequentvertical spreading of the fungus from one vascular strand to theother. These experime
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