OFFICE OF 
STATE ENTOMOLOGIST 
ST. ANTHONY PARK. MINN. 
Circular No. 28 
JAN. 20, 1914 
FUMIGATION OF GREENHOUSES WITH CYANIDE 
Fumigation with cyanide gas has come into general use to 
destroy scale ' insects upon citrus trees such as oranges, lemons, 
etc., the fumigation of nursery stock to destroy various insect pests, 
the fumigation of houses to destroy bed bugs, and also the fumi- 
gation of mills and grain elevators to destroy grain insects. 
Cyanide has also been used in the fumigation of greenhouses, but 
not as extensively as in the above cases. The reason for this is 
that oftentimes, the fumigation of the greenhouse results in injury 
to the plants growing there. 
In the fumigation of greenhouses, there are a number of factors 
to be taken into consideration. The most important factor is to 
have the greenhouse accurately measured, so that one can accu- 
rately estimate the exact dose of cyanide which is necessary to 
kill the insect pests and not destroy the plants. 
Fig. 1 shows a view of a greenhouse which has both the 
slanting roofs equal and the height of each side equal. Such a 
house is very easily measured and the number of cubic feet deter- 
mined. To estimate the number of cubic feet in a house of this 
kind, the height AB is multiplied by the width AE and the result 
multiplied by the length AH. This gives the number of cubic feet 
of space in the rectangular portion ABDE-H. The upper portion 
