FUMIGATION OF CITRUS PLANTS. 



19 



THE INFLUENCE OF SUNSHINE AT VARYING PERIODS AFTER FUMIGATION. 



Wliile experiments 10 to 19 clearly demonstrate the influence of 

 sunshine on plants exposed immediately after fumigation, the 

 following four experiments set forth the effect of this factor where 

 plants are placed in the sunshine four hours or more after treatment. 



EXPERIMENT 20. 



Condition during fumigation, shade, 62°-65° F. 

 Condition before fumigation, shade, 66° F. 

 Dosage, 1 ounce NaCN. 

 Date, September 21, 1915, 8-8.45 a. m. 

 Plants in each test, 3; total, 21. 



Results. 



Condition after fumigation. 



Shade, 

 79° F.i 



Shade, 

 90° F.2 



Sun, 76° F., 

 exposed 

 imme- 

 diately. 



Sun, 79° F., 



exposed 



after 30 



minutes. 3 



Sun, 80° F., 



exposed 



after 1 



hour. 3 



Sun, 84° F., 

 exposed 

 after 2 

 hours. 3 



Sun, 88° F., 

 exposed 

 after 3 

 hours. 3 



2 



2 



5 



4 



4 



3 



2 



i Equal to sun temperature throughout the day. 



2 Temperature held at 85°-91° F. all day. 



3 Plants removed from fumigatorium to shade (temperature approximately 70° F.) until placed in sun- 

 shine. Maximum sun temperature 94° F. at 1 p. m. 



EXPERIMENT 21. 



Condition during fumigation, dark, 58°-60° F. 



Condition before fumigation, shade 60° F. 



Dosage, 1^ ounces KCN. 



Date, March 21, 1915, 8-9 a. m. 



Plants in each test, 3; total, 27. 



Remarks: Plants were in a somewhat resistant condition. 



Results. 



Condition after fumigation. 



Shade, 

 64° F.i 



Shade, 

 90°-97°F.2 



Sun, 

 77° F., 

 exposed 

 at once. 3 



Sun, 

 77° F., 



exposed 

 after 5 



minutes. 3 



Sun, 



77° F., 



exposed 



after 15 



minutes. 3 



Sun, 



79° F., 



exposed 



after 30 



minutes. 3 



Sun, 



79° F., 



exposed 



after 1 



hour. 3 



Sun, 

 82° F., 

 exposed 

 after 2 

 hours. 3 



Sun, 

 84° F., 

 exposed 

 after 4 

 hours. 3 



i Temperature 64°-70° F. all day. 



2 Temperature fluctuated 90°-97° F. all day. 



3 Plants held in shade at 61°-62° F. between time of removal from fumigatorium and placement in sun- 

 shine. Maximum sun temperature 85° F. at 1 p. m. 



