56 



FUMIGATION FOR THE CITRUS WHITE FLY. 



Other precautions which it seems desirable to emphasize at this 

 time concern the avoidance of damage to the tents and trees. Tents 

 should never be dragged over the ground where the residue of the 

 jars has been poured out on the surface or where the material has 

 boiled over during the generation of the gas. The safest rule is to 

 avoid entirely the dragging of tents across sections of the grove 

 which have been recently fumigated. The residue or contents of the 

 jars after fumigating is very destructive to citrus trees if emptied 

 against the base of the trees. When emptied 3 feet or more from 

 the base of the trees there seems to be no danger whatever unless 

 roots are exposed, but to avoid all risk it is recommended that the 

 practice be adopted of burying the residue halfway between the rows, 

 as described under the subject of methods of procedure. Tents 

 should not be left during the day covering trees which are to be 

 fumigated at night, for the inside temperature is quite likely to be 

 raised to a point where the gas will cause excessive shedding of the 



foliage. 



EXPENSE OF FUMIGATION. 



FOR EQUIPMENT. 



The cost of the equipment, aside from the fumigating tents, is of 

 little importance. In procuring a set of tents one may either pur- 

 chase the material and arrange for the construction to be done by a 

 tentmaker according to directions, or the maker may provide the 

 material and furnish the tents according to specifications at regular 

 prices. It will be found advantageous to obtain quotations from sev- 

 eral tentmakers before placing an order. To give an idea of the 

 usual cost of fumigating tents in California, the following schedule 

 of prices recently quoted by a leading maker of fumigating tents in 

 that State is given: 



Table XII. — Schedule of prices for sheet and bell fumigating tents. 



