14 



BULLETIN" 1015, U. S. DEPARTMENT OF AGRICULTURE. 



(1) Those of plants apparently infected, determined by visual inspec- 

 tion only, and (2) those of plants actually infected, determined by 

 cutting the stems and noting the appearance of the tissues. 



Table 6. 



-Comparative resistance to wilt of several varieties of tomatoes m 

 Louisiana in 1920. 





Plants infected. 



Variety. 



Plants infected. 



Variety. 



June 25, 

 apparent 

 infection. 



July 11, 



actual 



infection. 



June 25, 

 apparent 

 infection. 



July 11, 



actual 



infection. 





Per cent. 

 6.6 

 6.2 

 6.3 

 5.0 

 15.0 

 13.2 

 1.2 



Per cent. 

 55.7 

 62.2 

 69.3 

 70.0 

 75.4 

 77.7 

 77.9 



Earliana 



Per cent. 

 47.6 

 24.5 

 58.4 

 78.3 

 60.1 

 80.6 



Per cent. 

 87.6 







90.7 







92.7 







96.1 





June Pink 



96.6 







97.2 



Livingston's Globe 







There is considerable difference between these varieties in per- 

 centage of plants apparently infected, but not so much in percentage 

 of plants actually infected. As apparent infection is somewhat 

 closely related to degree of infection, the percentages recorded in the 

 first figure column show the superior resistance of varieties developed 

 for resistance to wilt. However, the resistance of Livingston's Globe 

 was much higher in these tests than the writer has personally ob- 

 served. In a test of 87 strains of the Globe variety at the Arlington 

 Experimental Farm in 1920 the percentage of apparently infected 

 plants was much higher than for the Marvel, Norton, Arlington, 

 Columbia, or Louisiana Red. The Globe must therefore fluctuate 

 considerably in its resistance to wilt. 



The report in Table 7 by Mr. IT. G. Swingle, of Columbus, Ohio, 

 gives a fairly good comparison of the behavior of the Marvel variety 

 in wilt-infested soil in a greenhouse as compared with commercial 

 varieties. The Arlington, Columbia, and Norton varieties were used 

 in this test, but only on a small scale, as they are rather large, heavy, 

 and late for forcing:. 



Table 7. 



-Comparisons of wilt-resistant and nonresistant varieties of tomatoes 

 in a greenhouse at Columbus. Ohio, in 1919." 



Variety. 



Number 

 of plants. 



Average 

 yield 

 per 



plant. 



Average j y . ld 

 returns Vf" 1 



P er a?E 

 plant. acre - 





1,650 

 5,160 



Pounds. 

 4.76 

 3.23 



Tons. 

 Jl. 02 22 





.70 15 







a Swingle,U. G. Successful greenhouse tomato crop. In Market Growers' Jour., v. 25, no. 11, p. 7. 1919. 



