junei2, i9i6 Bacterial Wilt of Cucurbits 425 



tained an abundance of the typical stringy ooze which microscopic exami- 

 nation showed to consist entirely of characteristic bacteria. Seed ger- 

 mination and cultural tests similar to those described for the cucumber 

 gave negative results. 



During the latter part of September, 19 14, ripe Hubbard squashes 

 were collected from wilted vines at IMedina, Malone, and Constable, N. Y. 

 These squashes upon examination showed the same evidence of bacterial 

 wilt as did the cucumbers and cantaloupes referred to above, and in 

 addition a pure-culture isolation of B. tracheiphilus was made from the 

 Medina squash, which subsequently gave typical infections when inoc- 

 ulated into healthy cucumber and squash plants. Seed germination and 

 cultural tests from the seeds gave the same negative results as in cucumbers 

 and cantaloupes. 



STOMATAL INFECTIONS 



Two inoculation tests with cucumber and one with cantaloupe were made 

 during the summer of 191 5, using sterile- water suspensions of the wilt 

 organism (strain R230) . The plants were put into tight inoculating cages, 

 and the plants and walls of the cages sprayed with tap water. Two hours 

 later the plants were inoculated by spraying with a very cloudy suspen- 

 sion of bacteria from 7-day-old agar slants. Check plants were inocu- 

 lated by needle punctures from the same cultures. All the plants were 

 left in the cages tightly closed for 24 hours, and semiopen for two days 

 longer. The punctured checks wilted promptly, but no infection occurred 

 in the uninjured sprayed plants, although they were kept under observa- 

 tion for two months. Another test was made in March, 191 6. Three 

 young and three older cucumber plants and four young squash plants 

 were inclosed in a dampened inoculation chamber and sprayed with a 

 tap-water suspension of B. tracheiphilus (strain En58 isolated from 

 squash) from a 6-day-old beef-agar slant. Three hours later the plants 

 were again sprayed with this bacterial suspension. This culture was at 

 the same time tested by needle-puncture inoculations into the leaves of 

 two cucumber and two squash plants of the same varieties. The sprayed 

 plants were left in the inoculating chamber in a saturated atmosphere for 

 three days, after which they were held under ordinary greenhouse condi- 

 tions. After two months no infection had appeared in the sprayed unin- 

 jured plants, although the plants inoculated from the same culture by 

 needle punctures all developed typical wilt within one week after inocu- 

 lation. 



A fifth trial was made in April, 1916, using five young and five older 

 cucumber plants. All aerial parts were thoroughly sprayed mth a tap- 

 water suspension of the wilt organism from a beef-agar slant 6 days old 

 (strain Ensy). This culture was tested by needle-puncture inocula- 

 tions into cucumbers of the same age and variety. The latter inocula- 

 tions resulted in typical wilt, but the uninjured plants sprayed with the 

 bacterial suspension had shown no signs of infection after five weeks. 



