266 BACTERIA IN RELATION TO PLANT DISEASES. 



Inoculations of January 7, 1896. 



A set of inoculations was made in the hothouse at noon on cucumber {Cucitmis sativus), 

 pumpkin (Cucurbita pepo), squash [Cucurbita maxima), cow-pea (Vigna), tobacco (Nico- 

 tiana tabacum), common gourd (Lagenaria vulgaris), balsam apple (Momordica balsamina) , 

 and the vegetable sponge (Luffa acutangula) . The bacteria used were from a thin, nearly 

 colorless, wet-shining, very sticky growth (cucumber-strain) covering nearly the whole 

 surface of a slant agar (tube No. 4, December 31, which was inoculated from the interior 

 of vine 242 and yielded a pure culture) . The inoculations were made with a sharp-pointed 

 steel-needle and the culture was so sticky that an enormous number of bacteria must have 

 been inserted into the leaves. 



(25 1 .) Cucumber. This was a large vine. Many pricks were made on one leaf. The wilt appeared 

 on the seventh day in the pricked area to which it was then confined. Two days later the wilt had 

 moved slowly from the pricked area, and now involved about one-seventh of the blade the terminal 

 portion from the pricked area to each side and outward. The wilt had extended more rapidly up than 

 down. The rest of the vine was normal. The eighteenth day the terminal part of the stem had dry- 

 shriveled and the wilt was slowly passing downward. The whole vine finally shriveled to the ground. 



(252.) Cucumber. No pricks were made but a big loop of the sticky bacterial slime was put into 

 a fresh pistillate flower on and below the stigmas. The flower was near the apex of the stem. The 

 eighteenth day there was some possibility that the bacteria had passed into the fruit. It had changed 

 color throughout, i. c, it had become a dirty green. The fruit was 0.5 to 0.75 inch long at this time. 

 There had been no wilt of the leaves as yet. Up to March 4, however, there were no further signs. 



(253.) Pumpkin-seedling. Many pricks were made on a cotyledon. The inoculation failed. 

 Not even the whole of the cotyledon wilted. 



(254.) Pumpkin-seedling. Many pricks were made on the blade of the tender first leaf. The 

 thirteenth day the pricked part of the leaf was wrinkled and yellowish but not wilted. Five days 

 later one side of the pricked leaf had wilted. By March 4 (56 days) the pricked leaf had wilted to 

 the stem but there were no other signs of disease and the plant was very thrifty. 



(255.) Pumpkin-seedling. Many pricks were made on the small, delicate first leaf. The eighth 

 day the pricked apex of the blade was wilted and the following day the wilt involved about one- 

 fourth of the leaf. Four days later the pricked part of the leaf had dry-shriveled and the wilt was 

 extending, although the middle basal part of the leaf was still turgid as was also the petiole. Twenty- 

 four hours later the upper part of the petiole had drooped over. The eighteenth day the pricked 

 leaf had wilted and shriveled nearly to the stem and the cotyledons were beginning to droop. The 

 whole vine ultimately shriveled to the ground. 



(256.) Pumpkin-seedling. Many pricks were made on the tender, partially developed first leaf. 

 The thirteenth day about two-thirds of the blade of the pricked leaf had wilted, i. e., the pricked 

 apical area and the margins nearly to the petiole. Five days later the pricked blade and over half 

 of the petiole had shriveled. The whole vine shriveled to the ground after a time. 



(257.) Winter-squash-seedling. Many pricks were made on one of the big green cotyledons. 

 The thirteenth day there was a distinct wilt and loss of color extending from one group of pricks to 

 the edge of the leaf about 1 sq. cm. Five days later there was a bad droop of the pricked cotyledon. 

 Up to March 4, however, there had been no general wilt and the plant was still thrifty. Not even 

 all of the pricked cotyledon had wilted. 



(258.) Cowpea. This plant was 6 inches high and was just developing the third true leaf. Many 

 pricks were made on the apex of one of the first leaves. 



There was no result from the inoculation. 



(259.) Tobacco var. Little Oronoco. Many pricks were made on the apex of the blade of a 

 bright green leaf, 3X1.5 inches. 



There was no result from the inoculation. 



(260.) Common gourd (No. 226 of December 3, now inoculated for the third time). Many 

 pricks were made on the apex of the leaf-blade midway up. The seventh day there was a slight 

 flabbiness at the tip of the pricked leaf. Two days later there had been no decided change. Up to 

 March 4 there was no general wilt. 



(261.) Common gourd (No. 228 of December 3, now inoculated for the third time). Many 

 pricks were made on the apex of a leaf-blade midway up on the stem. The seventh day there was a 

 slight flabbiness at the tip of the pricked leaf. The ninth day there was no decided change and the 

 case was considered a doubtful one. ( >n March 4 the plant was still living and there had been no 

 general wilt. 



