junei.i92o Behavior of the Citrus-Canker Organism in the Soil 201 



The two series of pots were kept separated in the dense tropical woods 

 at Lamao. The inoculation and planting data with results are given in 

 Tables VII and VIII. 



Table VII. — Results of sprouting seeds and growing young plants of Citrus trifoliata in 

 pots of soil artificially inoculated with canker bacteria 



Pot No. 



I 



2 to 5 



6 to 10 



II to 20 



31 to 33 



34 

 35 to 40 



51 to 58 

 59 to 61 



Treatment cf 

 soil. 



Date of inocula- 

 tion. 



Sterilized . . Oct. 22, 1918 

 do ' do 



. . . .do do. 



Unsterilized, do. 



. . . .do do. 



.do. 

 .do. 



.do. 

 .do. 



.do. 

 .do. 



.do. 



.do. 



Date of planting 



Oct. 22, 1918 

 do 



Nov. I, 1918 

 Oct. 22, 1918 

 Oct. 27, 1918 



Results. 



.do. 

 .do. 



Nov. I, 1918 

 ... .do 



No trees 



9 trees, no in- 

 fections. 



10 trees, no in- 

 fections. 



31 trees, no in- 

 fections. 



7 trees, no in- 

 fections. 



No trees 



19 trees, no in- 

 fections. 

 ...do 



No trees 



Date of examina- 

 tion. 



Jan. 16, 1919. 

 Do. 



Do. 



Do. 



Do. 



Do. 

 Do. 



Do. 

 Do. 



Table VIII. — Results of sprouting seeds and growing young plants of Citrus trifoliata in 

 pots of soil naturally infected with canker bacteria in the orchard 



SUMMARY OF EXPERIMENT IV 



One hundred and thirty-three seedling Citrus trifoliata trees were 

 sprouted in soil pots. These pots had been inoculated wath the canker 

 organism, either by artificial or natural means, from 2)5 to 40 days previous 

 to the sprouting of the seeds. None of the seedlings at any time showed 

 canker, although they were kept for 45 days after they appeared above 

 the ground. The seedlings were from seed taken from heavily infected 

 C trifoliata fruits on badly infected C. trifoliata trees; there can be no 

 doubt as to the general susceptibility of the stock. The strain of the organism 

 used in inoculating the soil was the same as that which produced lesions 



