77 



Of course, too strong a dosage of gas will produce injury as 

 well as too severe spraying, and judgment is required, not only 

 to get a dose rightly proportioned to the size of the tree, but to 

 properly adjust it to conditions of the atmosphere and temperature. 



A damp atmosphere makes the tree more susceptible to burning 

 by the gas, and of course if fog or rain makes the tree really wet, 

 the fumigation must stop. A high temperature has a similar effect, 

 and a combination of a hot night and a damp atmosphere is very 

 dangerous. The same is true of a temperature below 32. Fumi- 

 gation can be done safely only in a dim light, and the night's work 

 should never begin in bright weather sooner than sunset. Very 

 bad burning of trees has often resulted from starting work too 

 early in the evening or continuing too late in the morning. 



We can not account, at least not fully, for some other unex- 

 pected results in fumigation work, and we are obliged to confess 

 that we do not fully understand this chemical process and its 

 adaptation to our needs yet. However, we know enough about it 

 to make decidedly the best killing of scale by its means, and with 

 the least harmful results to the trees of any process we have. 



How to Fumigate First, tents must be provided large enough 

 to cover the largest of the trees to be treated. Where there are 

 several sizes, if some of the tents are large enough for the biggest 

 trees, smaller ones can be used for the balance, or if only a few 

 trees are too large for the tents at hand, these may be covered 

 by using two or more tents, lapping the edges and closing the 

 joints as well as possible. Sometimes three or four tents are 

 applied around a very large tree, and one as a cap over the top. 

 The joints of the tents in such cases, will of course, leak gas some, 

 but surprisingly good results are obtained with careful work. 



The tents now universally used in this County are simply an 

 eight square sheet of sufficient size, made of various kinds of cloth, 

 but mostly canvas, from 8 oz. to 10 oz., or drill of about 6 oz. in 

 weight, double sewed, and with two rings attached by pieces of 

 rope, firmly sewed on at two adjacent corners, by which the tent 

 is drawn over the trees. 



One or more marks are painted directly across the canvas on 

 which each foot in length is shown by a short cross mark, each 

 of which is numbered like a tape line, so that when the tent is 

 on the tree this mark acts as a measure, showing the distance over 

 the tree. These marks are made with very heavy lines and large 

 figures so as to be easily read at night. 



