INSECTS AND INSECTICIDES 31 
economical of the poison and enables one better to tell when all 
parts of the plant have been treated. A good proportion is: 
Paris green.1 pound 
Common flour..*.25 pounds 
The advantages of flour over lime or plaster are, it helps bet¬ 
ter to stick the poison to the leaves and is not distasteful to insects. 
Particles of poison imbedded in a mass of plaster or lime would 
probably be avoided by most insects. Filling the blossom ends of 
apples with lime mixed with poison may drive the worms to eat 
their way into the apples where they will escape the poison 
entirely. 
The methods of applying dry poisons are chiefly two. If low 
plants, like cabbages and tomatoes, are to be treated, and the area 
to be covered is not too great, a very satisfactory method is to make 
a small sack—about ten inches long by five inches in diameter— 
of strong cheesecloth or other light muslin, fill half full with the 
mixture of poison and flour and then shake or jolt the sack over 
the plants. 
Where large areas are to be treated, or where it is necessary to 
make the application to trees or high bushes, some kind of dust 
gun or bellows is an advantage. Powder guns of different kinds 
are upon the market and some of them are being extensively ad¬ 
vertised at this time. These instruments have a place to fill, but 
I do not believe they can take the place of the watery spray for 
large trees, and particularly for the application of poisons for the 
destruction of the codling moth. 
4. scheede’s green (green arsenoid). 
Scheele’s green, also sold as u green arsenoid,’ 1 differs very little 
from Paris green in chemical composition, except in lacking the 
acetic acid. It is considered as effectual as an insect destroyer, and 
has a great advantage over Paris green in being much more finely 
divided, so that it remains in suspension in water for a much longer 
time. It is also cheaper in price. Dr. Marlatt, of the Division of 
Entomology, says it should replace Paris green as an insecticide. 
Apply either wet or dry, as recommended for Paris green. 
5. ARSENATE OF DEAD. 
This compound contains only about 20 to 25 per cent, of ar¬ 
senic acid, but has some important advantages over the other arsen¬ 
ical compounds. It is so completely insoluble in water that it may 
be used in almost any strength without injuring foliage and con¬ 
sequently is. least likely to injure plants that are most sensitive to 
arsenical poisons. When suspended in water this poison is so finely 
