15 



possible to treat trees also on a very dark or cloudy day. In CalU 

 fornia, however, at the time the gas treatment is made, such days are 

 infrequent, xlbout 50 trees of the largest size, 30 feet high or there- 

 abouts, can be treated in a night with an equipment of twelve or fifteen 

 tents (fig. 5). By the time the last tent is in place, the fumigation in the 

 first is completed, and it can be taken down and moved forward, and 

 so on with the others; thus the men at work handling the tents are kept 

 continuously employed. Working in the same way with smaller trees, 

 the number which can be treated in a single night is very considerable, 

 it being possible to gas from 300 to 500 trees, averaging 10 feet in 

 height, in eleven or twelve hours, employing 35 to -iO ring tents. 



SPRAYS FOR CITRUS TREES. 



It may often happen that gassing is impracticable or that the 

 expense of the treatment is not warranted. This last may be the case 

 where the rancher has not sutiicient capital to keep up thfe heavy 



Fig. 7. — Gasoline-power spraying outfit with four lines of hose in operation. 



outlay necessitated by the treatment of young stock which yields no 

 revenue. Gassing is also difficult and less desirable where, as for the 

 lemon in southern California, the low, open-center pruning is adoptted, 

 the trees under this system of pruning often having an expanse of 20 

 feet, with a height of scarcely more than 6 feet. This open system 

 of pruning and more straggling form of growth, on the other hand, 

 makes the lemon easier to treat with liquid sprays, and under such 

 conditions spraying will probably prove more practicable and profit- 

 able than gassing. Nevertheless, where lemon trees are of a form and 

 size to admit of it, and the crop warrants the expense, gassing is always 

 to be recommended. 



The expense of spraying is not heav}^, compared with that of gassing. 

 In most of the citrus districts of California where spraying is practiced 

 to any extent there are individuals who make a business of treating 

 orchards at a charge of a cent a gallon for the liquid applied, or about 



