October, '21] serverin & others: beet leaf hopper 407 



The pale green adults of the spring brood invaded the beet fields at 

 King City about April 22 or 23. When the foliage was disturbed with the 

 hand during the early quiet morning, the adults were sluggish on account 

 of the low temperature and usually hopped or made short flights and by 

 this method it was determined that there was approximately one adult 

 to ten beets in the experimental plots on May 2. 



After the first application of "5% and 10% Nicodusfat the rate of 

 about 50 and 75 pounds per acre respectively, there was no apparent 

 reduction in the number of leafhoppers. In later treatments there was 

 no noticeable decrease in the number of hoppers with "5% Nicodust" 

 at the rate of about 75 and 100 pounds to the acre nor with " 10% 

 Nicodust" at the rate of about 75 pounds per acre. 



The percentage of curly leaf before the first application of the dust 

 in each lot of 7.G acres and two checks was determined by an examin- 

 ation of 2000 beets as follows : May 12, 15% in plots before treating with 

 "5% Nicodust," check 19%; 22% in plots before treating with "10% 

 Nicodust," check 12%. The percentage of curly leaf after the applica- 

 tion of the dust was determined from 100 beets in each plot and 200 

 beets in the two checks as follows : 



Treated with "Nicodust 5%," 

 Plot 1, May 21, 26%, May 28, 34%, June 14, 66%. 

 Plot 2, May 21, 26%, May 28, 30%, June 14, 56%. 

 Plots, May 21, 18%, May 28, 21%, June 14, 52%. 

 Plot 4, May 21, 19%, May 28, 18 %o, June 14, 47%. 

 Average 22.2% 25.7% 55.2% 



Check May 21, 29%, May 28, 34.5% June 14, 63%. 



Treated with "Nicodust 10%." 

 Plot 1, May 21, 24%, May 28, 26%, June 14, 43%. 

 Plot 2, May 21, 24%, May 28, 29%, June 14, 57% . 

 Average 24% 27.5% 50%. 



Check May 21, 20%, May 28, 27.5%, June 14, 50.5% 



The cost per acre of one application of "Nicodust 5% and 10%" and 

 labor including two men, team and gasoline was as follows: 



Cost of UK) lbs. "Nicodust 5%" (Sj 13c per lb. !513.00 



Cost of applying dust 1.25 



Total $14.25 



Cost of 100 lbs. "Nicodust 10%" (g. 19c per lb. $19.00 



Cost of applying dust 1.25 



Total $20.25 



