. Journal of Agricultural Research. t wasfound, September 28, which suggested that the inoculation had been Fig. 4.—Diagram showing arrangement ofinoculated plants and roots connectingthem with parent Crystal White black-berry. No. 134. Nursery stock, P, P,planted in 1920. Other plants indicated,larger circles, were young shoots in May,1921, when the experiment was made;small circles attached, new shoots, frame probably covered areaabout NEA. Numerals represent dis-tances in inches. Signplus + indicatesplant infected May, 1922, when dug;roots bearing plants A and B broken offin
. Journal of Agricultural Research. t wasfound, September 28, which suggested that the inoculation had been Fig. 4.—Diagram showing arrangement ofinoculated plants and roots connectingthem with parent Crystal White black-berry. No. 134. Nursery stock, P, P,planted in 1920. Other plants indicated,larger circles, were young shoots in May,1921, when the experiment was made;small circles attached, new shoots, frame probably covered areaabout NEA. Numerals represent dis-tances in inches. Signplus + indicatesplant infected May, 1922, when dug;roots bearing plants A and B broken offin digging; sign — indicates uninfectedplant. See text and figure 5 for furtherexplanation. 222 Journal of Agricultural Research Vol, XXV No. s successful, whereas in reality over 120 separate infections had failure to pick out the infected plants lay in the fact that it is notuntil the second year the rust has lived in the blackberry that the canesbecome so infected secondarily by invasion of mycelium from the peren-. FlG. 5.—Root system of nursery stock of blackberry No. 134 planted Hay, 1920, dug May, 1922. Letteringhas same significance as that in Figure 4. Infectc 1 plants A, B. C, D, E. and F arise from roots con-nected with the original stock at three different levels. The roots shown here arc entirely free frommycchum. Sec figure 4. Original root crown at X, present crown at Z. nial base that they show the peculiar features mentioned. Canes prima-rily infected remain for the most part quite normal and blossom as usual,since the upper parts are free from the parasite. The results of theinfection experiments are given in Table I. Aug. 4,1923 Systemic Infections of Rubus with Orange-Rusts 223 Table I.—Primary infection of the blackberry with sporidia of the short-cycled orange-rust, IQ2I PlantNo. 95 92 9394W. 97112 134336337342 9598 135344353354355356 35796 99 lOI 105 B 125 B 136 154 330 331 343 352369370371372373377Z33334335338340341345358 359360 393361
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