10 
BUREAU OF PLANT QUARANTINE 
[Jan. -Mar. 
E. Lead arsenate, field treatments 
Material. — Powdered acid lead arsenate. 
Condition of soil. — The soil must be friable. The treatment is recommended only 
for soils that are slightly acid or neutral in reaction. 
Season. — When the treatment is to be used as a basis for certification between 
September 20 (re-treatment) or October 1 (initial treatment) and the following 
June 15, the treatment must be completed by July 1. Because of differences of 
seasonal conditions it may, in other years, be necessary to modify these dates. 
Dosage. — For initial treatments lead arsenate must be applied at the rate of 
1,500 pounds per acre, which is equivalent to approximately 35 pounds per 1,000 
square feet. 
For subsequent re-treatments, lead arsenate must be applied in sufficient 
quantity to restore the original concentration of 1,500 pounds of the insecticide 
per acre. The quantity to be added in the re-treatment will be determined by 
analyses. 
Application. (1) Plants growing in rows. — The ground must be in good tilth. 
Lead arsenate may be applied by either of the following methods: (a) The lead 
arsenate may be broadcast or applied with a suitable distributor. At least 2 
inches of soil from the ridge between the plants in the row and from about the 
base of the plants must be removed into the space between the rows of plants. 
(6) At least 2 inches of soil from the ridge between the plants in the row and from 
about the base of the plants must be removed into the space between the rows of 
plants. The lead arsenate may then be broadcast or applied with a suitable dis- 
tributor. After either procedure has been completed, cultivate at least three 
times, adjusting the cultivator for the third operation so that the soil will be 
thrown toward the tows of plants to obtain at least 3 inches of poisoned soil 
about the base of all plants. 
{2) Individual plants. — The treatment of individual plants is essentially a hand 
operation. The soil must be treated in a manner to obtain the same conditions 
as are required for trees planted in rows. The area to be treated must never be 
less than 10 feet in diameter and must be at least 6 feet greater in diameter than 
the diameter of the soil ball to be removed with the tree. 
Safety zone. — In addition to the area desired to be certified there shall be 
treated a 3-foot strip of land around the entire plot, coldframe, hotbed, etc. No 
plants may be certified from this strip. 
Marking. — Nurserymen shall be required to furnish suitable stakes at least 4 
inches square and at least 30 inches long to be placed on the boundaries of certified 
plots. Proper designations will be stenciled on the stakes by the Department. 
In the case of coldframes, hotbeds, etc., having fixed boundaries, proper designa- 
tion will be made on such coldframes, hotbeds, etc., and no stakes will be required. 
3. MISCELLANEOUS TREATMENTS 
A. Fumigation of bananas in refrigerator cars with liquid hydrocyanic acid 
Material. — Liquid hydrocyanic acid. 
Caution. — Hydrocyanic acid gas is very poisonous and because of the readiness 
with which it is liberated, care should be exercised during the entire process of 
fumigation not to breathe the fumes. Gas masks must be used when applying 
the liquid. 
Equipment. — Two metal trays having an area of about 2 square feet, equipped 
to be suspended about 24 inches below the hatch openings. Two tin cups with a 
capacity of 3 ounces each. Four screens made of cotton netting on light wooden 
frames which will fit tightly in hatch openings. 
Condition of car. — Only refrigerator cars in good condition should be used to 
insure against leaks. 
Temperature. — The temperature inside the car during the period of fumigation 
must be at least 75° F. 
Dosage. — Six ounces of hydrocyanic acid per car. 
Application. — The doors should be closed tightly and the ice drip plugged. 
Remove one insulating plug from each ice bunker and suspend a tray therein. 
Place on tray a tin cup of 3-ounce capacity with string attached to handle and 
long enough to fasten at the top of the bunker. Fill each cup with 3 ounces of 
liquid hydrocyanic acid and pour into trays by tipping with string. Replace plug 
and close hatch covering tightly. 
Period of fumigation. — The car must be kept sealed for a period of 2 hours after 
the liquid hydrocyanic acid has been applied. 
