COBB S DISEASE OF SUGAR-CANE. 4! 



Louisiana No. 74. 



Inoculated row of tall cane (same remarks about loss of labels apply as before) : 



Cut out from first clump 3 young, very leafy shoots, varying from 3 to 6 feet in height. Sound 

 externally and within. Observed also 2 or 3 buds just pushing out of the ground. 



Old shoot, sound at the base, leafless for about 4 feet. Very leafy above; leaves green. Cross- 

 sectioned from the top downward. Stem sound within all the way down. 



Another old shoot. A few red bundles at the base of the stem on cross-section. Stem leafless 

 for lower 6 feet, and most of the leaves above are only partly alive. Terminal bud dead, evidently 

 due to injury by jamming against the top of the house, i. e., cut by closing the ventilators, as in the 

 other cases of dead terminal leaves and buds. Sound immediately under the terminal bud. Stem 

 continues sound on cross-section for a distance of many feet. First evidence of a reddened vascular 

 bundle about a foot from the ground. This stain runs out, and no others are visible. Stem sound. 



Another old cane. Sound at the base. This bears label 820. Leafless for the first 6 feet; leafy 

 above. Leaves not white-striped. Cross-sectioned from the top downward. Stem sound within 

 for a distance of many feet. No evidence anywhere of anything wrong. 



The next cane (apparently an old one) is rotted, nearly to the ground. Sound under the rotted 

 part. The rot, I believe, is not due to any inoculation ; in fact, I think the cane grew after the date of 

 the inoculation ; it is hardly tall enough to have dated from so long back. 



Next cane, an old one. Sound at the base; naked for a distance of 5 feet. Upper leaves green, 

 battered somewhat, and red-striped in some places along the midrib. Sound within from the top 

 downward a distance of many feet. 



Next clump: Five young shoots of varying heights (3 to 5 feet). All very leafy and healthy 

 looking. Sound within. 



Old shoot. Sound at the base. This bears label 8oa. Small diameter. Leafless for the first 

 5 feet. Most of the upper leaves dead. Sound at the top on cross-section; continues sound for a 

 distance of many feet. No internal evidence of disease anywhere in the stem. 



Another old stem. This is a large cane, leafless nearly to the top. Top dead and rotted. Stem 

 sound under the rotted portion. Continues sound for a distance of many feet. Sound at the base. 

 Within about one foot of the ground a red bundle appears, and a little lower down there are several 

 others. These continue through the next internode, but there are not many of them. I believe 

 these particular red bundles are due to the bacterial inoculation ; at least they have all appearances of 

 being that type of disease. They are few in number and the stem as a whole is sound. The bundles 

 have the characteristic of being red and yellow by turns. 



Another old cane. Large cane leafless nearly to the top. This has been topped within the last 

 few weeks to shut the house, and some of the bundles under this top part have red stains in them. A 

 little lower down this red stain disappears. Stem continues sound on cross-section for many feet. 

 The first indications of anything wrong are about 2 feet from the earth. There are some dead cells in 

 the center and red stain in a very few bundles. This runs out about 6 inches lower and the stem 

 from that point down is sound. 



Another clump: Some very young shoots; these are sound. 



An old cane leafless nearly to the top. Has two labels, Nos. 970 and 976. Sound at the earth 

 and within from the top downward a distance of many feet. First red stain about 2 feet from the 

 ground, restricted to a few bundles in the middle of the stem. This disappears a little further down, 

 that is, it is restricted to one node and two internodes. 



Another old stem, naked nearly to the top. Upper leaves not white-striped. Stem at the top 

 sound on cross-section ; continues sound all the way down. 



Another clump: Four young shoots of varying ages, 2 to 5 feet high, and very leafy. Sound 

 within. 



Shoot about 8 feet high. Very leafy, except near the base; leaves very healthy. Sound within. 

 This undoubtedly grew after the inoculation. 



Old, large shoot, naked for the first 4 feet, top leaves green. On cross-section the top is sound 

 and the stem continues sound for a distance of many feet. No indications anywhere of bacterial ooze 

 or red stain in the vessels. 



Another old stem. Leafless for the first 4 feet. Green leaves above. Sound at the base. 

 Cross-section of the upper part of the stem sound. Stem continues to be sound on cross-section all 

 the way down. 



Another old stem. Leafless to the top. Top part rotted. The rot is not like the bacterial rot ; 

 it is a soft, pale brown uniform rot. It stops quite suddenly at a certain node, and from this on the 

 stem is sound on cross-section clear to the base. 



Old stem. Sound at the base. Leafless to the top. Top part soft-rotted. It had been short- 

 ened to get it inside of the house, and like some others that have rotted at the top, it may have been 



