THE GLADIOLUS FANCIER’S GUIDEBOOK FOR 1934 
Page 7 
climates, at least, there is but a very small 
fraction of over-wintering of the thrips in 
the field, in the ground not at all but 
almost entirely on bulbs in storage. 
Every precaution you can take to keep 
the thrips from falling, blowing, flying or 
crawling upon the dug bulb should be taken. 
We can think of nothing worse than bringing 
the bulbs with their tops still on into a 
warm place of storage, if the plants were 
even but lightly infested. 
As soon after digging as your bulbs are 
fairly well dried, use the common NAPTHA- 
LENE FLAKES treatment. It is safe 
both to the user and to the bulbs, during 
their dormant period of storage, even 
when an overdosage is used, provided 
the bulbs are fairly well dried. One ounce, 
sprinkled on each 100 large bulbs or 
equivalent in bulk of smaller sizes, is suf¬ 
ficient if bulbs are stored in closed bottom 
container. If screen bottom or in onion 
sacks, double the amount. Will kill insects 
promptly and gases will continue for several 
weeks, killing the larvae as soon as hatched. 
But note they will not hatch under 50 
degrees. Do not cover the bulbs as evapora¬ 
tion takes place constantly and to prevent 
it will make the bulbs first damp, then 
mouldy, then susceptible to rot and dis¬ 
eases. Applying the flakes in a closed 
paper bag is safe for a few weeks if bulbs 
be dry, since some moisture can escape. 
If the flakes have not entirely evaporated 
by the time little root knobs and eye sprouts 
emerge, showing bulb is no longer dormant, 
shake out any remaining. Do not use any 
napthalene in the trench at planting time 
since it is safe only to the dormant bulb. 
Perhaps the most practical method of 
gassing large quantities of bulbs (if there is 
any sign of thrips infestation), making a 
complete kill of both the insect and the 
eggs in but 24 hours, is the ETHYLENE 
DICHLORIDE 75% — CARBON TETRA¬ 
CHLORIDE 25% mixture. Many large 
growers have used this method satis¬ 
factorily. However, anything but strict 
attention to the rules of this method may 
result in damage to your bulbs. Some 
amateurs, non-attentive to details, have 
damaged their bulbs by careless calcula¬ 
tions. You need 1 oz. to 5 cu. ft. or 14 lbs. to 
1000 cu. ft. Write to me for detailed in¬ 
structions (have a few hundred printed) and 
write for prices (10 lb. tin is minimum 
purchase) to The Carbide & Carbon Chemi¬ 
cals Corp., 30 East 42nd St., New York City. 
LYE treatment. Tests by the U. S. Dept. 
Ent. have proven the lye solution, commonly 
advocated in the northwest and elsewhere, 
to be little more effective than plain, cold 
water, not even making a complete kill of 
the insects, let alone the eggs. And you 
understand these thrips just make guinea 
pigs look like 4th rate novices when it comes 
to raising a family. 
HOT WATER treatment. An easy 
method if you have but a small quantity of 
bulbs and an accurate thermometer. Prefer¬ 
ably at planting time as it tends to shorten 
the dormant period. U. S. Dept. Ent. ad¬ 
vises you can get a 100% kill of both insect 
and eggs by merely covering the bulbs with 
hot water at about 115 degrees F. for 20 
minutes. Harmless to the bulbs if you keep 
under 122 degrees and ineffective if allowed 
to go below 112. Keep at 115 by adding hot 
water as needed. 
Probably the best method of checking 
bulb diseases is to soak the bulbs (unhusked, 
O K) 7 hrs. or overnight, night before plant¬ 
ing in a CORROSIVE SUBLIMATE (mer¬ 
curic chloride) solution. This process will 
also kill thrips and their eggs but remember 
soaking processes are only advisable just 
before planting. Dissolve 1 oz. of the powder 
first in a little hot water, then pour into 
734 gal. of water, preferably above 60 de¬ 
grees. This must be poured into a non- 
metal container, such as a crock, wooden 
pail or tub. No difference if bulbs are then 
planted wet or dry. Varieties kept separate 
in cloth bags. Solution weakens with use, 
so replenish at least 34 if used again. Safe 
to the hands but this solution is a deadly 
poison and must be used and disposed of 
with extreme care. 
Our bulbs get the napthalene treatment a 
week or two after digging, the Ethylene 
gassing late January and the corrosive 
sublimate before planting. Advertising 
“treated” bulbs means little unless you 
know the method used and when last used. 
If thrips appear on your plants they must 
be controlled before the bud spikes emerge 
from the foliage. Watch for any silvery 
gray streaks on the foliage. If permitted to 
increase unmolested they will extract- 
juices from the buds resulting in a burned 
appearance, they will eat streaks of color off 
the petals even before they unfold and if 
they unfold at all, the petals may crimp up 
their edges and dry to a dull brown. Even 
the young, lemon colored thrips may do this 
damage to the bud so it is important to kill 
such adult thrips as may arrive before they 
lay eggs, also because the young have the 
bad habit of staying inside the bud and 
crevices of the plant where they are hard to 
reach with insecticides. The silvery gray 
(feeding) streaks on the foliage, in badly in¬ 
fested cases, turn brown, stopping both 
plant and bulb growth. 
A modification of the Canadian Dept, 
formula by the U. S. Dept, of Entomology of 
1 rounded tablespoon of Paris Green, 2 lbs. 
of brown sugar, to 3 gal. of water, kept agi¬ 
tated and wetting the entire leaf surface is 
a bit expensive for large plots, moreover, 
it often burns the lower leaf or two, necessi¬ 
tating cutting spike higher in such event to 
allow foliage to mature the bulb. 
