Insects and Insecticides. 
23 
The advantages of flour over lime or plaster are, it helps better 
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 will drive the worms to eat 
their way into the apple, where they will probably escape the poison 
entirelv. 
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 advertised 
at this time. These instruments have an important place to fill, but 
I doubt very much if 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. scheele’s green (green arsenoid). 
Scheele’s green, also sold as “ green arsenoid,” 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 LEAD. 
This compound contains only about 25 per cent, of arsenic 
acid, but has some advantages over the other arsenical compounds. 
It is so completely insoluble in w~ater that it may be used in almost 
any strength without injuring foliage and consequently is least 
likely to injure plants that are most sensitive to arsenical poisons. 
When suspended in water this poison takes the form of a flocculent 
precipitate that remains suspended a long time without settling, and 
consequently can be more evenly distributed than most arsenical 
mixtures. Its third point of superiority is in its adhesive qualities 
when applied to foliage. Applications made to foliage in the latter 
part of May at this Station could plainly be seen upon the leaves the 
first of September. The disadvantage of the poison is in its not 
being as destructive to the insects that eat it as are the other 
