12 



BULLETIN 818, U. S. DEPARTMENT OF AGEICULTURE. 



Table IY.— Soil disinfection tests with tomato and lettuce plants grown in 8-inch pots, 

 with hot-water treatment, in May and June, 1918. 



(Two kinds of soil were used: Soil A was nematode and fungus infested; B was uninoculated fresh green- 

 house soil.] 







Number 

 of plants 



Root infection on June 12 

 (end of experiment). 



Plant notes. May 28. 



Kind of plants, soil used, and treatment 





Nematode. 



Rhizoc- 







of soil-filled pots. 





>> 



2 











• 



Height 









: 





^ 



^ m 



, 



Disease. 





6 

 'A 



03 





i 



S 

 S 



2 



"3 . 



ft 



H 



(inches). 







Ph 



o 



• o 



m 



1^ 



s 



^ 



^■3 



fS 







Tomato plants: 

























Soil A— 

























Boiling water poured into pots— 



























1 



67 



66 







2 



15 



23 



1 



1.5 



4 to 4J 





2,000 c. C-... 



2 



73 



70 







2 



20 



27 











4 to 4i 

 4i 



•None.i 





3 



64 



65 











35 



54 



3 



4 







1 



65 



64 



























4 to 4i 





3,000 c. c 



2 



70 



66 



























4i 

 4i 



• Do.i 





3 



85 



71 























. 







1 



70 



55 



























3i 





4,000c. c 



2 



56 



57 



















1 



2 



3i 



4 



■ Da.i 





3 



49 



45 































1 



72 



40 



16 



7 



17 



100 



40 



100 



2 to 3 



(2) (') 



Check (soaked with cold water). 



2 



50 



22 



17 



3 



1 



95 



20 



90 



li to 2 



{") {') 





3 



57 



42 



26 



10 



4 



95 



40 



95 



2 to 24 



{■") i?) 



Soil B- 

























Boiling water poured into pots— 



























1 



87 



48 



























44 to 5 





2,000c.c 



2 



56 



54 



















1 



2 



4 



■None.i 





3 



60 



52 



















1 



2 



34 







1 



60 



68 



























5 to 54 





3,000c. c 



2 



60 



73 



























6 to 64 

 4 to 44 



■ Do.i 





3 



63 



61 































1 



57' 



52 



















1 



2 



44 to 5 





4,000 c.c • 



2 



48 



48 



























5 



■ Do.i 





3 



54 



51 



























6 







1 



49 



30 











2 



7 



20 



66 



. 14 



(«) (') 





2 



32 



31 











18 



58 



27 



87 



4 to 5 



(') (8) 



Check (soaked with cold water). 



3 



4 



40 

 45 



38 

 22 





 14 







7 



5 



1 



13 

 100 



16 

 22 



42 

 100 



3 to 4 



4 



(«) (') 

 (') (') 





5 



43 



44 











22 



50 



15 



34 



4 



(.-') («) 





6 



42 



47 











17 



36 



4 



9 



2 



(') (8) 



Lettuce plants: 

























Soil A— 

























Boiling water poured into pots — 



























1 



77 



60 







1 



13 



23 











3 to 34 





2,000 c. c 



2 

 3 



63 

 50 



73 

 31 





 





 



13 

 2 



18 

 6 





 3 





 10 



3 to 4 

 3 



None. 









1 



45 



47 



























3 to 34 





3,000 c. c 



2 



66 



52 



























3 to 34 

 34 



■ Do. 





3 



64 



52 































1 



40 



48 



























24 to 3 





4,000 c. c 



2 

 3 



43 

 ,37 



38 

 30 





 





 





 





 



1 







2.5 

 



24 to 3 

 3 



I Do. 









1 



45 



13 



12 



1 







100 



10 



77 



2 



(«) 



Check (soaked with cold water) . 



2 



30 



22 



20 



1 



1 



100 



1 



4 



1 to 14 



}(") 





3 



43 



26 



21 



4 







95 



12 



46 



2 



Soil B— 

























Boiling water poured into pots— 



























1 



71 



37 



















1 



3 



34 





2,000 c. c 



2 

 3 



77 

 55 



35 



46 





 





 





 





 



3 

 



9 

 



3 

 3 



[-None. 









1 



63 



51 



























34 





3,000 c. c 



2 



66 



62 



























4 to 44 



• Do. 





3 



49 



47 



























3 







1 



40 



43 



























34 





4,000 c. c 



■ 2 

 3 



55 

 59 



34 

 34 





 





 





 





 





 





 



34 to 4 



4 



■ Do. 









1 



45 



44 











8 



18 



5 



11 



2 







2 



32 



23 











2 



9 



23 



100 



3 





Check (soaked with cold water). 



3 



4 



30 

 33 



30 

 23 





 20 





 3 



5 

 



17 

 100 





 5 





 22 



3 



34 



Do. 





5 



16 



13 











7 



54 



4 



31 



2 







I 6 



47 1 31 











7 



22 







1^ 





1 Plants vigorous. s Nematode stem galls, many. & Nematode stem galls, few. 



* Damped-off, few. < Damped-ofl, many. « Damped-off, 1. 



' Nematode stem galls, none. ^ Several plants damped-o£f and some with stem galls. 



8 Damped-ofi, none. w No damping-off, but several plants with stem galls. 



