EXPERIMENTS WITH THE DAISY ORGANISM. 35 



July 24, 1907: Additional photographs were made (PI. IV, fig. 2). 



DAISY ON EUROPEAN GRAPES. 



Inoculations of April 3, 1907 (Smith and Brown). 



Three small, slow-growing shoots of as many vines were inoculated 

 by needle pricks from a 48-hour agar culture. 



Result. — June 27, 1907: One only of the three vines developed a 

 tumor — a small growth about half an inch long, one-fourth inch broad, 

 and perhaps one-eighth inch high (PI. V, fig. 1). It was on Muscat 

 Hamburg. The failure of the other two (Golden Hamburg and 

 Champion Hamburg) is attributed to poor condition, the plants hav- 

 ing made scarcely any growth. 



Inoculations of April 11, 1907 (Brown). 



A Golden Hamburg and Champion Hamburg were each inoculated 

 in the laboratory with agar streak cultures 5 days old. The plants 

 were small and covered with scales, which were removed before inocu- 

 lating. The plants were then set out in the greenhouse. 



Result. — May 1, 1907: The Golden Hamburg was dead; the other 

 had made no growth and no gall had formed. 



Inoculations op May 9, 1907 (Brown). 



A dozen Black Hamburg vines were taken from the pots, washed 

 carefully, and 9 of them inoculated with agar streak cultures 4 days 

 old. They were well-rooted cuttings. The inoculated plants were 

 treated all in the same way, each receiving 20 to 25 punctures on the 

 green shoot, underground stem, and young root. The checks were 

 punctured in the same manner with a sterile needle. 



Result. — July 20, 1907: Small galls had formed on each inoculated 

 plant, but only on the green shoots. The galls produced were not 

 like the regular grape galls. The checks did not develop galls. 



Inoculations of May 14, 1907 (Brown). 



Young, well-rooted cuttings 3 to 4 inches tall were taken from the 

 pots, washed carefull}^, and 9 plants inoculated on both root and 

 shoot, 20 to 25 punctures being made on each. The cultures used 

 were 3-day-old agar streaks. Three checks were held. The vines 

 were afterwards repotted. 



Result. — ^July 20, 1907: Knots had formed on all of the shoots 

 inoculated. The checks were free from knots. 



Inoculations of June 9, 1907 (Townsend). 



Vine No. 490, Black Hamburg, was inoculated with a 4-day-old 

 agar culture. 



213 



