INJURIOUS AND. BENEFICIAL INSECTS OF CALIFORNIA. 491 



CHEMICAL PROPORTIONS 

 Potassium Cyanide (98-99%) 



Potassium cyanide 1 ounce 



Sulphuric acid \ fluid ounce 



A\ ater 3 fluid ounces 



Sodium Cyanide (129-130%) 



Sodium cyanide 1 ounce 



Sulphuric acid U fluid ounces 



Water 2 fluid ounces 



METHODS OF PROCEDURE 



For an outfit of thirty or thirty-five tents five men are required to 

 operate to an advantage. Two men pull the tents and kick in the 

 edges around the bottom. One man, the taper, takes the measure- 

 ments of the tree and calls them off to the man who weighs out the 

 cyanide. After determining the dosage this man also empties the 

 generators from the row just finished and has them ready for the 

 next trees by the time the chemical cart arrives. The man who 

 weighs the cyanide determines the dose on the schedule from the 

 measurements called out by the man who measures the tents. The 

 cyanide man also lifts the tent so that the last man who measures 

 out the acid and water in the generators may place them well under 

 the tree, after which the cyanide is added. In no case should the 

 acid man touch the tents. While the chemical men are dosing one 

 tree the taper is getting the measurements for the next tree ready 

 in advance. In brief, the procedure is as follows: putting the tents 

 over the trees, measuring and dosing. The string of thirty tents 

 can be easily dosed within forty-five minutes or an hour. Methods 

 of procedure vary considerably, the above being general. 



For extra large trees a special tent-hoisting apparatus (Fig. 488) 

 has been devised by Mr. C. E. McFadden, with which a 70 or 80-foot 

 tent can be easily and quickly put over the largest citrus trees. 



DOSAGE 



The dosage is variable and depends upon the pest to be treated. 

 It is usually stated in terms of the number of ounces of cyanide used. 

 Several field schedules in which the dosages are tabulated are recom- 

 mended. R. S. Wbglum recommends his Schedule No. 1 (potassium 

 cyanide) for red scale, yellow scale, purple scale and black scale 

 and Dosage Schedule f for black scale under favorable conditions. 

 He also recommends Dosage Schedule f (sodium cyanide) for black 

 scale, red scale, yellow scale and purple scale (Fig. 487). 



Prof. C. W. Woodworth has found in actual fumigation work thai 

 the proportion for purple scale, red scale and black scale is about 

 7|— 5f-4, respectively. 



Tent leakage is a very important question which has not yd been 

 sufficiently worked out in practice. Prof. Woodworth has calcu- 

 lated a series of tables to correspond with different, degrees of ten! 

 leakage. Several instruments have been invented to determine the 



