350 



Hop " Canker " or " Growing-off." 



[July, 



later in the season when bearing hops. Some of the diseased 

 bines were quite detached from the rootstocks, and others showed 

 various stages in the process of becoming separated. Many of 

 the dead bines were found to be bearing Fusarium pustules when 

 examined in the hop-garden; in some cases the pustules had 

 developed while covered with two or three inches of soil. In 

 very rare instances the separated bines were found to have 

 produced tufted growths of adventitious roots, mostly from the 

 nodes, in the region between the plane of separation and the 

 surface of the soil. 



It is noteworthy that this Branding garden was on land which 

 had not previously borne hops and the plants were only about 

 four years old; the soil. was loamy and certainly not to be 

 described as a wet soil. In a few hills all the bines had been 

 killed and only such hills were, in practice, grubbed up and 

 destroyed. As a rule 1 to 3 out of the six bines trained up 

 from a hill had been killed ; such hills were not grubbed up. 



A number of hills which had lost 1 or 2 bines during the 

 summer were marked and examined in the following March, 

 when it was found that in each case some or all of the remaming 

 " straps " (bases of the bines) were diseased, a slight pull 

 usually being sufficient to sever the connection with the root- 

 stock ; in one hill only were all the " straps securely con- 

 nected with the rootstock and, on cutting, it was found that 

 two were sound throughout while the third showed a trace of 

 decay on one side. 



Where the straps were not wholly destroyed the decay 

 in every case was at the lower end, the upper end being still 

 alive and bearing young shoots. This indicates that the disease 

 spreads from the crown of the rootstock into the straps. One 

 such strap which was carefully examined showed a sharply 

 marked margin at the upper limit of the diseased tissue which 

 extended to about the middle of an internode, the lower node 

 bearing dead buds, the upper living ones. The same sharp 

 demarcation of the brown dead portion was also seen on cutting 

 the " strap " longitudinally, and on making a microscopic 

 examination fungus mycelium was found in the brown tissues 

 up to one or two layers of cells from the sound tissues ; mycelium 

 was not found actually in the cells not discoloured. The myce- 

 lium present was proved to be that of the Fusarium. 



It was the practice in this garden, at the time the hills were 

 cut, to remove the straps almost immediately and burn 

 them ; at the time of the visit (March) this was being done, the 



