340 NEW YORK STATE MUSEUM 



small trees, and, where such are reasonably distant from other infested 

 trees, an attempt might be made to exterminate the pernicious scale by- 

 fumigation. A box tent 6x6 and 8 feet high, with a hood 7 feet high and 

 a sod cloth some 6 inches wide, was made of 8 ounce duck which was 

 thoroughly painted with boiled linseed oil. Rings for guy ropes were 

 provided at the upper corners, and the tent was lifted by a rope attached 

 to the extremity of the hood. The form of the tent was kept rather con- 

 stant by using a light frame composed of four side pieces and slender 

 posts at each corner {see pi. 10). The tent was handled with the aid of 

 a 35 foot mast and an 8 foot gaff and tackling, and was raised bodily and 

 dropped over the tree. The mast could be fixed to a heavy wagon when 

 used on level ground where the trees are some distance apart. This 

 tent and outfit cost $^S, but. as only one was made, much better terms 

 could be secured if several were ordered. The cost of treatment, aside 

 from apparatus, is comparatively little. The secret of doing this work 

 economically consists in having enough tents, so that the men will not 

 have to wait but will be kept busy changing one after another. A Httle 

 experience will enable those handling the tent to raise it from one tree, 

 swing it over another, lower it, fix it in position, place the chemicals and 

 have the fumigation started within a short time. Five to 10 or more 

 tents could be used in a large orchard to advantage. The economical 

 use of a small number of tents would necessitate some employment near 

 at hand to occupy spare minutes. Dormant trees can be fumigated in 

 this latitude, even when the sun shines, without any apparent injury to 

 the trees. The gas should be allowed to act for 35 minutes or a little 

 longer, and i ounce of potassium cyanid (98% pure) to each 75 cubic 

 feet of space, with an equal amount by liquid measure of the best grade 

 of commercial sulfuric acid (specific gravity 1.83) and thrice that amount 

 of water, did not appear to injure the trees in the least, while every scale 

 insect was apparently killed. The above amounts for 100 cubic feet of 

 space gave equally good results. A better proportion, according to Prof. 

 Johnson, is i ounce cyanid, i}4 ounces acid and 2}( ounces water. The 

 cyanid and acid are both very dangerous substances, and should be 

 handled with the greatest care. The cyanid should be conspicuously 

 labeled, kept in a tight, covered can and not taken therefrom till it is to 

 be used. The sulfuric acid is capable of producing horrible burns, and 

 it should be guarded most carefully. The acid should be turned into the 

 water slowly, the mixture being constantly stirred. A glazed earthenware 

 crock is one of the best vessels for the chemicals, and it should be placed 

 under the tent near its middle but not close to the trunk of the tree. 



