16 



BULLETIN 1040, U. S. DEPARTMENT OF AGRICULTURE. 



nozzles were used. Distillate-soap powder emulsion, soap powder, 

 and water were used, as shown in Table 2, and data were gathered 

 on the efficiency of the different solutions. 



Before the spraying started a man was sent through to remove 

 the heavily infested bands, dip them in pure distillate, wring them 

 out, and place them to one side to dry. 



Table 2. — Summary of spray operations against the dtrophilus mealyhicg. 



Spray. 



Total 

 number 



of trees 

 sprayed. 



Average 



numter 



of trees 



per 



tank. 



Average 



spray 



time 



per 



tank. 



Average 

 numter 



of 



gallons 



per 



tree. 



Effective- 

 ness of 

 spray. 



5 per cent distillate-soap powder emulsion 777 



Water 69 



40 pounds soap to 200 gallons water 42 



59 



34 



- 42 



Min. 

 58 

 85 

 45 



3.4 



5.7 

 4.8 



Excellent. 

 Poor. 

 Do. 



Both the water and soap-powder treatments were discontinued, as 

 it was found to be impractical in application to get a thorough clean- 

 up of the Qigg masses. The distillate-soap emulsion was quicker in 

 application and more effective. 



The bands were replaced shortly after the completion of the spray 

 work, and field observations made from time to time throughout the 

 following year. Though some mealybugs appeared under the bands 

 following the spraying, they were completely controlled by natural 

 enemies and required no further treatment. Throughout the fall and 

 winter no mealybugs were apparent, and in the spring of 1920 so few 

 mealybugs appeared under the bands that hand treatment was all that 

 was required. The grove is now commercially clean, and there has 

 been a marked increase in the grade of the fruit. 



The data obtained in this experiment not only demonstrated the 

 practicability and efficiency of the distillate-soap emulsion but also 

 demonstrated the advisability of proper pruning before spraying. 

 The trees on this grove were low on the ground and it was difficult 

 to treat the trunks owing to low branching and inside growth. In 

 consequence of this condition it took much more material and a longer 

 time to make the application. The cost of spraying was as follows : 



Removing and dipping bands, 1 man, 1 day $3.00 



16J tanks spray : 



330 pounds soap powder, at $0.07 per pound 23. 10 



165 gallons distillate, at $0.07 per gallon 11.55 



Two men, at $4 per day, 2 days 16.00 



Team, at $4 per day, 2 days S. 00 



Gasoline and oil, 2 days 2.50 



Total 64. 15 



Cost of $0,072 per tree. 



