48 EXPERIMENT STATION. [Jan. 



ever, we have to spray large elms, Ibe question is an entirely 

 different one. 



A few years ago some large elms located in the public square 

 in one of our cities were sprayed by the same methods used by 

 the best orchardists, at an expense of something like $1G per 

 tree. These trees, to be sure, were imusually large, but the cost 

 was so great that in our opinion it set a limit to the amount of 

 spraying which should be undertaken by such methods, ]\rost 

 of the former spraying of shade trees was done by this very ex- 

 pensive method at a cost of $1.50 upwards for trees 14 to 18 

 inches in diameter. In much of this early spraying the Ver- 

 morel, Ware or similar fine spray nozzles on poles were used, 

 and spraying had to be done at close range for the best results. 

 The early gypsy moth work was done in this same way, any other 

 method at that time being considered useless. This method en- 

 tailed a great deal of climbing on the part of the sprayers, and 

 was a slow and costly process. 



Some years ago the Gypsy Moth Commission abandoned these 

 fine nozzles and close-range methods of spraying, and now em- 

 ploys large nozzles and large hose, and exceptionally high pres- 

 sure is obtained from powerful machine sprayers. "With the 

 larger area which has to be treated at the present day the older 

 method would not only prove prohibitory on account of the ex- 

 pense, but also because of the time involved. Practically all the 

 spraying with these large modern machines is done from the 

 ground, doing away Avith the necessity for ladders and for climb- 

 ing trees ; and by the use of one or more long lengths of hose 

 large areas can be treated from one spot. This method of spray- 

 ing trees is very effective and very much cheaper, the average 

 cost of spraying woodlands being something like $12 or less per 

 acre. With this method the spraying mixture is delivered to the 

 nozzle through a large strong hose under a pressure of 200 to 

 250 pounds, the high pressure breaking the spray up into a fine 

 mist. The spray has considerable spread when broken up, which 

 is a desirable feature in treating woodlands and country road- 

 sides, but on this account it is more or less objectionable for use 

 on residential streets in cities and towns, as it is likely to dis- 



