Poisons Used In Spraying
( Originally Published Early 1900's )
For Insects That Chew.
ARSENATE OF LEAD.
This poison is used very extensively. It can be secured for reason-able price, is ready to use at any time, does not easily injure the foliage and is the only poison that can be safely used in the lime-sulphur sprays.
Injury to tender foliage like the peach has occasionally occurred by spraying with arsenate of lead and water when the foliage was moist from dew or rain. If necessary to spray tender foliage (peaches or Japanese plums) at such a time it would be well to add 3 to 5 pounds of slaked lime to every 50 gallons of the spraying material.
Arsenate of lead is usually sold in kegs or "kits" or small barrels in the form of a paste. Some companies have it in a powdered form. This form, usually costs twice as much or more per pound as the paste form and since it does not contain much water only one-half the amount in weight should be used as is recommended for-the paste form.
A simple, easy way to work the thick pasty arsenate of lead into a thin, smooth paste (as it should be before using either alone or in some-thing) is to put the amount required in a keg; add water and churn with a dasher. This is much quicker than to use a paddle.
Always use lime with Paris green, it makes the poison stick better, besides greatly reducing the danger of burning the foliage.
For spraying from a barrel, the writer has found the following method very useful: Place from one-quarter to one-half pound of good lump lime, or unslaked lime, in each of three or four tin pails which will hold about three quarts or less. Old cans or crocks will answer just as well. Add enough hot water to slake it into a thin cream or paste. Now add to each lot, one-quarter pound of Paris green, previously weighed out, and placed in paper bags, stir while the lime is hot and allow to stand for some time. Now measure out about forty-four gallons of water in your spraying barrel, and make a mark that will show how high it comes in the barrel, add the contents of one tin pail (viz., one-quarter of a pound of Paris green and one-half pound of quick-lime slaked) into the forty-four gallons of water in the barrel. Stir well and spray. The pails or crocks can be used one at a time and refilled occasionally so that the stock is always on hand ready for use.
ARSENITE OF SODA-KEDZIE FORMULA.
This form of poison was originated at this Station by the late Dr. R. C. Kedzie.
This is a cheap, effective poison that can be prepared at home. It is used by many of the grape growers of Michigan in combination with the Bordeaux mixture. It cannot be used in the lime-sulphur sprays. If used alone—as is sometimes done for potato bugs—slaked lime must be added or the foliage will be burned.
The formula is:
White arsenic 2 pounds
Sal Soda (commonly called washing soda) 8 pounds
Water 2 gallons
Boil these materials in any iron pot or kettle not used for other purposes for about 15 minutes or until the arsenic dissolves, leaving only a small muddy sediment. Put this solution into a jug or other vessel that can be closed tightly and label "Poison."
One quart of this solution is equal to 1/2 pound of Paris green. For most spraying one quart in 50 gallons of water (with some lime) or Bordeaux mixture will be sufficient.