24 FUMIGATION METHODS 
be reduced to 0.10 to 0.15 gramme cyanide. Asarule, 
it is not desirable to fumigate such plants as cedars, 
pines, etc. 
Seeds of various kinds can be fumigated in nor- 
mal amounts of gas with perfect safety, the varying 
physiological effeéts depending upon the condition of 
the grain or seed, whether dry or moist, upon the 
amount of gas used, the length of time exposed, and 
the atmosphere in which it is confined, whether dry, 
damp, or saturated. This is treated more fully later 
in another chapter. 
Low-growing plants may be fumigated for the de- 
struction of the root aphis, leaf-rollers, and other 
insects, but the work must be done with the same care 
as for other plants. Lettuce, cucumber, and canta- 
loups are very easily injured if the plants are damp, 
even with smallamounts of gas. Intests made by Pro- 
fessor E. D. Sanderson, of the Delaware Agricultural 
Experiment Station, upon young cantaloups after a 
shower, he found the plants were injured in 0.40 
gramme of cyanide per cubic foot for ten minutes. Pre- 
liminary tests should be made with o. 10 to 0.20 gramme 
for ten to twenty minutes before an entire house is ex- 
posed. Professor Sanderson has shown also that straw- 
berry plants freshly dug and fumigated in a box will 
withstand 0.20 gramme cyanide fifteen minutes. His 
tests show that this strength will kill the aphids on the 
roots and not injure the plants. Other details are given 
in a later chapter on this topic. 
