INSECTICIDES AND EQUIPMENT FOR CONTROLLING INSECTS 29 
quart of bran) is adequate for treating a garden 50 feet by 50 feet 
in size. By broadcasting thinly and evenly, pets and birds will be 
unable to gather up enough of the material to be poisoned. Any par- 
ticles of the material which adhere to tender plants should be 
dislodged to avoid injury. 
On soil which has been in sod or which was weedy the previous 
season, it is well to apply poisoned bait as insurance against cut- 
worms, especially before setting out plants or before the plants appear 
above ground. 
To make a poisoned bait for ants, sowbugs, and millipedes, mix 1 
part (by volume) of paris green with 9 parts of sugar and sprinkle 
the bait over the soil. Avoid sprinkling it on tender foliage, other- 
wise severe burning may result. 
An effective poisoned bait to control mole crickets is prepared by 
mixing— 
For small For large 
quantities quantities 
WANE alteno nel Mase tie See Re Ses 12.5 pounds. 100 pounds. 
Sodium fluosilicate___________ == 2 I -pound: 8 pounds. 
ATURE hr ic es a OR es eS z. _ to moisten. to moisten. 
Apply at the rate of 20 pounds per acre. 
Caution.—These baits are poisonous and must be stored in la- 
beled containers so that they will not be used for human or animal 
consumption. 
- Bran is usually available locally at feed stores or mills. Some 
feed: stores sell prepared poisoned baits. 
PYRETHRUM, OR INSECT POWDER? 
One of our oldest insecticides and one of the most generally useful 
is pyrethrum. Pyrethrum powder isa plant product and is obtained 
by grinding the flower buds of the plant Pyrethrum cinerariaefolium, 
a plant which belongs to the same botanical family as chrysanthe- 
mums. The source was originally Persia and Dalmatia, and more 
recently Japan, but now Kenya Colony, Africa, supplies pyrethrum 
to this country and our allies. The toxic ingredients of the flowers 
are the pyrethrins I and II, which together occur in Kenya flowers 
to an average of about 1.3 percent. In the country of origin the 
unopened flower buds are harvested, dried, and baled for export. 
In the United States the flowers are ground and used for making 
extracts containing the toxic principles, or are ground fine and used 
as powder. 
Pyrethrum loses part of its toxic ingredients in a few days when 
exposed to air and light. Even in airtight metal containers there is 
some loss of pyrethrins after several months. 
Pyrethrum has several distinct advantages; it is comparatively 
harmless to higher animals, and in dosage sufficient to kill insects 
leaves no poisonous residue. It is principally a contact insecticide, 
and: one of its chief disadvantages is the lack of residual effect, 1. e., 
only insects touched with it are killed. For this reason pyrethrum 
has not proved satisfactory for use against the most important fruit 
insects, particularly where the period of attack may extend over 
several months. 
1 Wartime conditions have led to certain restrictions on the use of pyrethrum insecticides, 
and these restrictions are subject to change dependent upon the supply. For up-to-date 
information on the subject consult the War Food Administration, Chemicals and Fertilizers 
Branch, Chemicals Division, Washington 25, D.C 
