THE NATIONAL NURSERYMAN. 
7 l 
HOW TO FUMIGATE. 
Explained by Orlando Harrison of Berlin, Md.— Certainty of Ef¬ 
fects—The Question of Injury— Warning That Rules Must Be 
Observed Closely—Much Yet to Be Learned Re. 
garding Fumigation—Process Is Expensive. 
Orlando Harrison, of Berlin, Md., read the following paper 
at the Chicago convention: 
Why do we fumigate and what we are fumigating for ? Not 
because the enemy is here but generating gas for fear he may 
enter. Up to this date, there has never been found a single 
case of San Jose scale in our county. Probably there is not 
another state in the Union that has been as thoroughly hand, 
picked from orchard to orchard as Maryland, and hundreds of 
cases have been found. Our state entomologist, Professor 
W. G. Johnson, has done a great work throughout the state 
You have doubtless read all about it and were it not for the 
good management in which this work has been done it would 
have been an entire failure to have attempted it. The amount 
this investigation has saved the fruit grower is beyond estima¬ 
tion, although it is expensive for the nurseryman to begin 
with. But one dollar spent in this way may save the fruit 
grower thousands. 
The object of the fumigation first was to prevent the spread 
of the dangerous San Jose scale and we are willing to do this 
to keep the fruit grower from fumigating and uprooting trees 
after they had been set only for a few years. A part of the 
best orchards in the state, where this was not discovered in its 
infancy, were totally destroyed. If there be thorough fumiga. 
tion, the black aphis, which sometimes winters over on the 
roots of the trees, will be killed and we will have no complaint 
of the young trees being killed by the aphis in the early spring 
after being set in the orchards. . , 
The next point is how we fumigate. We have two large 
rooms built especially for this purpose, 13 x 16 x 10 feet; 
sheathed and double coated with cyclone building paper 
large double doors to admit a wagon, built on the same style 
as refrigerator car doors. Movable cleats are used at the bot¬ 
tom, to be sure they are perfectly tight and one window and 
one small door, yet I consider a refrigator car or a furniture 
car, paper-lined, equally as good for the purpose. After the 
trees are put in, the room is closed tight except the small door 
where we place a snuff jar inside and pour in water 40 ounces 
sulphuric acid 27 ounces, potassium cyanide ounces. The 
door is quickly closed tight for 30 minutes. At the expiration 
of this time the doors are thrown open, but no one is allowed 
to enter the room for at least ten minutes and by that time the 
deadly gas has escaped sufficiently to allow one to enter safely. 
It may be well that different sizes of rooms be built, as in our 
large rooms it would cost the same to fumigate one bundle 
of trees as it would a thousand. Our entomologist tells us 
that from experiments tried he gets best results when he uses 
25 grains, little less than an ounce of potassium cyanide, 1 l /i 
ounces by meausure of sulphuric acid, best grade commercial 
i-| ounces water for every 100 cubic feet of space enclosed, 
yet this amount can be used for every 75 feet if desired, biq 
not necessarily. 
The question may present itself to some one’s mind, Are 
we sure that this gas will kill insecls ? ” There is no question 
about it. If the gas is properly generated and handled it will 
destroy every living creature you put in the room and if you 
wish to test the strength of the gas, before fumigating throw in 
a cat, rat or any other worthless creature and note the result, 
which will be instant death. We have never known a single 
failure, and we have cautioned our men to be very particular 
about handling this, as one must remember that potassium 
cyanide is one of the most deadly poisons known, and that 
there is nothing more destructive to animal life than the inha¬ 
lation of hydrocyanic acid gas, and one should never get care¬ 
less in handling this deadly poison. Unless rules are strictly 
observed life is in danger. After the fumigation is over, in 
emptying the refuse from the jar, great care should be taken in 
covering same, as if left open in the reach of any kind of fowl 
the result would be the same as with the cat in the other ex¬ 
periment. We throw this on the compost heap and utilize it 
for fertilizer purposes. 
Can we fumigate without injury to trees ? We can, most 
assuredly, if trees are in perfectly dormant condition and they 
might be allowed to remain in the room for hours and even 
over night without injurious effect at the strength we now use 
the gas; but if the trees are allowed to be fumigated two or 
three times we find that the roots will be affected or dried out. 
Our entomologist says that it will take about eight times the 
standard strength to injure the trees in any way. June-budded 
trees will not stand fumigation as do the one-year trees, as 
they grow later and start out earlier and are not as well ma¬ 
tured as the one-year trees, hence there has been serious dam¬ 
age done by fumigating them. Trees can only be successfully 
fumigated late in the fall and winter after the leaves have 
fallen and I consider it a risk in late spring as there are some 
varieties that push bud much earlier than others and one is 
taking a great risk just at the time the bud has swollen. I 
don’t think fumigation can be done in large cellars success¬ 
fully to use gas-strong enough to be effective where there are 
different kinds of fruit trees packed damp, as some will doubt¬ 
less have swollen buds. 
The question now arises, are we working intelligently ? My 
candid belief is that fumigation where it is necessary is the 
nurseryman’s duty to the fruit grower and no one should ever 
complain of the extra cost of same. But if the whole country 
gets on its feet and says that every tree must be fumigated 
that is grown, we will have more complaint about the first of 
June when it comes pay day than the nurserymen have ever 
heard of. While there will be some benefited there will be 
numbers of cases where there will be losses of trees by fumiga¬ 
tion unless there is a perfect system, and some experimenting 
along this line done a little more thorough before the whole 
thing leaps at once. 
Is it expensive? Yes; handling trees at a season when one 
hour is worth more than two in the summer is surely no en¬ 
couragement during the packing season to add any extra labor 
that can be avoided. The ingredients are bought from our 
state officials at wholesale. It is not necessary that we buy 
from them, but it is a matter of convenience to the nursery¬ 
men. To fumigate one of our rooms the cost is 40 cents for 
ingredients each time and we ofttimes have to fumigate a half 
dozen times a day or more, but usually arrange for dinner hour 
and night for this purpose so far as possible. Me are willing 
to fumigate and expect to continue if necessary, but we hope 
the time is near when our fumigating rooms can be used foi 
grafting houses or some other purpose that there might be 
