100 BOARD OF AGRICULTURE. [Pub. Doc. 



to be used, the parties in charge of the work, knowing their 

 own resources in the matter of skilled labor, and having ob- 

 tained quotations from reliable manufacturers, should be able 

 to decide readily which form of insecticide is cheapest for 

 their purpose. 



For the elm-leaf beetle and the gypsy moth it is desirable 

 to use the insecticide at the rate of 5 or 6 pounds actual 

 arsenate of lead to 100 gallons of water. For the brown- 

 tail moth, tussock moth and fall web worm, 4 pounds actual 

 arsenate of lead to 100 gallons of water are sufficient. 



Several park superintendents and city foresters have found 

 advantage in adding glucose when using arsenical insecti- 

 cides, the theory being that this material causes the poison 

 to adhere in a superior manner to the foliage ; and this at 

 one time was our practice in the work against the gypsy 

 moth. Careful experiments, however, involving chemical 

 analyses of foliage sprayed with the same quantities of arse- 

 nate of lead but with and without glucose, showed no in- 

 crease where the latter was used. This result was confirmed 

 by picking foliage from the sprayed trees several weeks 

 after the spraying, and feeding it to caterpillars. The death 

 rate in the two cases was practically the same. There can 

 be no harm, however, in using the glucose, and it is pos- 

 sible that its addition results in a better suspension and dis- 

 tribution of the poison. 



Not less important than the subject of insecticides is that 

 of spraying outfits. Of these it may be truly said that their 

 name is legion, and a glance through the catalogues of 

 pump manufacturers will show an assortment of outfits suit- 

 able for spraying almost any kind of crop or tree. While 

 there are doubtless hundreds of outfits suitable for use on 

 shade trees, it will be my purpose to mention only a few 

 standard forms, which experience has shown to be of high 

 value for this specific purpose. 



First let us consider the needs of the owner of a few shade 

 trees. In many cases he cannot afford, and does not require, 

 the high-priced outfits suitable for park work on a large 

 scale. He can get satisfactory results from an outfit suited 

 for ordinary orchard work, with a slight additional expense 



