WILT OF CUCURBITS. 245 



(104a.) Summer Squash (Cucurbita sp.)- This vine was about 2 feet high at the time of inocu- 

 lation. It was pricked on the apical part of the blade of a leaf toward the top of the vine. 



The seventh day the pricked leaf had turned yellow and had become flabby on the pricked side 

 but it was the lowest leaf and I could not tell whether the wilt was due to bacteria or to other causes. 

 One day later the pricked leaf had whoUy collapsed and shriveled. The other leaves were normal. 

 Up to February 25 there had been no further wilt and no bacteria were found in the vessels. There 

 was a small pocket on one side of the stem between the epidermis and sclerenchymatic ring in one place 

 where a section was cut. This was filled with small bodies resembling bacteria but none were found 

 in the deeper tissues. This plant was crowded in a 4-inch pot. 



(1046.) Summer Squash. This vine was growing in the same pot as 104a. It was about 15 

 inches high and was pricked on the apical part of the blade of a leaf toward the tip of the vine. 



The sixth day one side of the pricked leaf showed a faint trace of the wilt. The following morn- 

 ing half of the pricked leaf had wilted and had begun to shrivel and hang down. The blade of a small 

 leaf 0.5 inch above had also collapsed. All the other leaves were normal. Twenty-five hours later 

 both of the wilted leaves had shriveled. The rest were turgid. Six days later, the fourteenth day 

 after inoculation, the rest of the leaves had wilted but the stem was still turgid. It was then brought 

 into the laboratory and examined. Sections of the stem were cut in the vicinity of the pricked leaf 

 (above and below) and also an inch farther up. There was not a trace of bacilli in the vessels or paren- 

 chyma. Many vessels were full of tyloses. The plant was erect and only about 15 inches high. It 

 was growing in a small pot and had been overtopped and partly crowded out by a larger plant 

 growing in the same pot. Some mildew was growing on it. 



(105a.) Summer Squash. This vine, which was about 2 feet high and was in blossom, was 

 pricked on a side lobe of a well-developed leaf. Many very small punctures were made. 



On February 25 there was no wilt and no bacteria were found in the vessels or parenchyma. 

 (1056.) Summer Squash. A vine about 15 inches high, growing in the same pot as the preced- 

 ing, was pricked on the apical portion of a well-developed leaf. 



There was no wilt and an examination after 53 days showed no bacteria in the vessels 

 or parenchyma. 



(106.) Tomato (Lycopersicum esculenlum). A thrifty but watery vine about 2 feet high, growing 

 in a 4-inch pot, was pricked on one leaf and also very thoroughly the whole length of a middle inter- 

 node including its two nodes. Thousands of living bacteria were put in. 

 No result. 



(io6a.) Check plant in the same pot. 



(107a, b.) Tomato. Two very healthy but rather watery vines about 20 inches high were inocu- 

 lated: one was pricked very thoroughly the whole length of a middle internode and its two nodes, 

 the other was pricked on one leaf only. 

 No result. 

 (107c.) Check. 



(io8a.) Muskmelon (Cucumis melo). A small muskmelon vine was pricked on the blade of one 

 leaf. 



The eighth day there was a small wilted place on the apex of the pricked leaf, arising from the 

 needle-stabs. Twenty-four hours later one-third of the apical portion of the pricked leaf had wilted. 

 The tenth day all of the pricked leaf had wilted. January 31 the last leaf shriveled. The next day 

 the plant was examined. There were no bacilli in the vessels of the stem and the barest trace of 

 them in the petiole of the pricked leaf. None of the vessels were stopped up. Toward the end this 

 plant was badly attacked by mildew, and its death must be ascribed to this fact and to the small pot, 

 although it was infected by the bacteria. 



(1086.) Muskmelon. This vine, which was small and was growing in the same pot as the pre- 

 ceding, was pricked on the blade of one leaf. 



The morning of the sixth day the pricked leaf showed a wilt spot on the side of the blade near 

 the margin. This was in the pricked area and included only about one-twentieth of the blade. 

 Twenty-four hours later about one-third of the pricked leaf had wilted and the following morning 

 three-fourths of the leaf-blade had become flabby and wilted. The petiole and the other leaves were 

 turgid. The next morning the whole of the pricked blade had wilted and also that of the first leaf up. 

 The petioles were still turgid. The next day (afternoon) the upper part of the stem had wilted. The 

 vine was cut and put into alcohol for sections. Bacteria were demonstrated in the bundles of the stem 

 by a microscopic examination. 



(io8c.) A check melon in the same pot remained free from the disease. 



(109a.) Muskmelon. This was a small vine and was pricked on the blade of one of the leaves. 



The fifth day three-fourths of the pricked leaf had wilted. The following morning the whole 



of the blade of the pricked leaf had collapsed. The eighth day the pricked blade was dry shriveling. 



