1921.] 



The Control of Onion Smut. 



447 



Plot (4) 2 11). of salt worked in on Sept. Ut. 



Plot (5) 21b. each of soot and salt worked in on Sept. 1st. 



Plot (G) Untreated control. 



Plot (7) 2 lb. of lime worked in on Sept. 1st. 



Plot (8) lib. of Nitrate of Soda worked in on Sept. 1st, followed by 

 a similar top-dressing after sowing (Sept. 3rd). 



Plot (9) Top Sin. of soil removed, burned and replaced. 



Across these plots, seed, treated as under, was drilled on Sept. 

 2nd in rows 12 in. apart by means of a Planet Junior single 

 row drill : — 



Series (1) 8 rows drilled with 2 oz. of seed mixed with 14 lb. sand. 

 Series (2) 4 rows untreated seed as control. 



Series (3) 4 rows (2 oz.) seed soaked in water two days and dried. 



Series (4) 2 rows (1 oz.) seed soaked in O'o per cent, sulphuric acid 

 for two days and dried. 



Series (5) 2 rows seed soaked in 0"5 per cent, acid, dried and dusted 

 with 0"07 grms. paraform just before sowing. 



Series (6) 4 rows seed soaked in 1 per cent, acid for two days and 

 dried. 



Series (7) 4 rows treated as in (6) but using 5 per cent. acid. 

 Series (8) 2 rows treated as in (6) but using 10 per cent. acid. 

 Series {[)) 2 rows treated as in (6) but using 10 per cent, acid for 

 1 hour. 



Series (10) 4 rows seed shaken up with 0'14 grms. of paraform. 

 Series (11) as in (10) but using 0*28 grms. of paraform. 

 Series (12) as in (10) but using 0"56 grms. of paraform. 



This trial gave 108 different combinations of seed and soil treat- 

 ments ; the part where Series (2) crossed Plot (6) acting as control . 

 Counts were made of the number of healthy plants in the middle 

 foot of each row of seed along the untreated plot ; this gave the 

 effect of seed treatment. Another count was made of the number 

 of healthy plants in the middle foot of each plot along the un- 

 treated seed rows ; this gave the effect of soil treatment. 



Effect of Seed Treatment. 



Efect of Soil 



Treatment. 



Series (1) average 



= 13 



Plot (1) average 



= 9-5 



Series (2) average 



= 10 (control) 



Plot (2) average 



= 14-75 



Series (3) average 



= 25-25 



Plot (3) average 



= 14-5 



Series (4) average 



= 12.5 



Plot (4) average 



= 15-25 



Series (5) average 



= 18-5 



Plot (5) average 



= 11 



Series (6) average 



= 12 



Plot (6) average 



= 10 (contro 



Series (7) average 



= 14-5 



Plot (7) average 



= 22-5 



Scries (8) average 



= 4-5 



Plot (8) average 



= 1-5 



Series (9) average 



= 26 



Plot (9) average 



^ 3 



Series (10) average 



= 16-5 







Series (11) average 



-.21 







Series (12) average 



. . 14-25 







