342 NEW YORK STATE MUSEUM 



Prof. W. G. Johnson in Maryland, are substantially as follows : A good 

 frame, covered outside with 11^x12 inch Virginia pine boards and 

 1^x4 inch batting. The interior, including the floor, was lined with 

 two-ply cyclone paper, over which four inch flooring was laid. The 

 doors should be made double, refrigerator style, hung with heavy hinges 

 and with bolts at top and bottom and a lock in the middle. There should 

 be a second opening either on the sideor roof so as to permit ready ventila- 

 tion. Trees fumigated in a freight car are very liable to serious injury, 

 and it should not be attempted. A second fumigation should be avoided 

 as the trees may be much damaged. A small room about 4x5x7 is ex- 

 ceedingly convenient, even when there is a large one, as it economizes 

 chemicals in the fumigation of small lots of trees. 



The cubic contents of a room should be carefully calculated and the 

 necessary chemicals measured out. Ordinary dormant nursery stock 

 will stand i|- ounces (avoirdupois) of potassium cyanid (98% pure) to 

 100 cubic feet of space, according to Mr Sirrine, while for immature 

 stock, bud sticks, etc. but f ounce should be used. Prof. Sirrine recom- 

 mends the following proportion : i^ ounces cyanid, if-ii fluid ounces 

 sulfuric acid and 4^ fluid ounces water for matured stock, and f ounce 

 cyanid, f fluid ounce acid and 2^ fluid ounces water for immature 

 stock. Allow the gas to act from 40 to 60 minutes. I have obtained 

 very satisfactory results with the formula given under orchard fumiga- 

 tion ; but this latter is undoubtedly good and possibly more economical. 

 Trees in leaf or those with buds started can not be fumigated with safety. 

 The cost of fumigating nursery stock is very sHght, One man constructed 

 a house large enough to accommodate 8000 trees of first class size at an 

 expense not to exceed $30. A person with considerable experience in 

 this line finds that trees can be fumigated in quantity at less than ^c 

 apiece. 



Great care should be exercised in this work as well as when treating 

 orchard trees. Special pains should be taken to air the fumigating room 

 thoroughly before allowing any person to enter. The doors should be 

 open at least 10 minutes. This gas is very deadly, nearly odorless and 

 too much care can not be exercised. 



