Conversion tables and equivalents for use in work relating to insect control

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Title:
Conversion tables and equivalents for use in work relating to insect control
Physical Description:
21 p. : 27 cm.
Language:
English
Creator:
Nelson, R. H
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:
Edition:
Rev. ed.

Subjects

Subjects / Keywords:
Weights and measures   ( lcsh )
Insect pests -- Control   ( lcsh )
Genre:
bibliography   ( marcgt )
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references (p. 20-21).
General Note:
Caption title.
General Note:
"May 1952."
General Note:
"E-517, revised."
Statement of Responsibility:
by R.H. Nelson.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030271281
oclc - 18994116
System ID:
AA00023018:00001

Full Text
UBRARY
TATE PL4tKl j.3RD


E-517, revised


United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine



CONVERSION TABLES AND EQUIVALENTS FOR USE
IN WORK RELATING TO INSECT CONTROL

By R. H. Nelson
Division of Stored Product Insect Investigations


Contents


Page


Mass ........... ............................. 2
Capacity liquid measure ........... ................... 3
Equivalents for teaspoonful, tablespoonful, and cup .......... 5
Capacity dry measure ........... ..................... 5
Linear, square, and cubic measure ......... ............. 6
Diluting insecticidal chemicals ......... .................. 9
Equivalent quantities for various quantities of water ... ...... 9
Concentration on the basis of percentage of toxicant ... ...... 9
Concentration expressed in parts per million ............. ...13
Dosage equivalents and relationships ..... ................ ...13
Dusts and soil insecticides ....... .................. ...13
Weight-volume relationships in dosage estimation ..... ..16
Dosage estimates for row crops ........ ............... 17
Fumigation ......... ......................... 17
Miscellaneous .............. ......................... 19
Capacity of sprayer tank ......................... 19
Diluting miscible liquids by volume ................ 19
Temperature conversion .......... ............. 20
Literature cited ............ ....................... ...20





-2-


In the literature on economic entomology the weights and measures
used in expressing concentrations and dosages of insecticides may be in
one or more of three systems--the United States, the imperial (British),
and the metric. Since information on the relationships and equivalents
in these systems is not always readily available to entomologists in the
field, it has been assembled here for their benefit. The data on equiva-
lents are taken principally from publications of the National Bureau of
Standards (4, 5) and the International Critical Tables (6). A comparative
discussion of United States and British units by Bearce (1) and a paper
by Irwin (3) were sources of valuable information.
Tables of equivalents for use in diluting insecticides, methods of
calculating concentrations on the basis of active ingredients, and certain
other miscellaneous information useful to entomologists working with
insecticides have also been included.
The measurement equivalents are carried out to sufficient decimal
places to furnish accurate figures for precise laboratory work. They
can be rounded out at the decimal place best suited for the equipment
of the individual worker. The concentration equivalents have been
carried out one to three places. In recommendations for practical use
it is suggested that values be given as whole numbers or in steps of
one-half wherever possible without gross error.

MASS

The basic units of the United States and British imperial avoirdupois
systems differ in definition, but are equal for practical purposes. There
are certain differences in terminology between the two systems that
should be noted. A stone of the imperial system is 14 pounds. That
system also uses 112 pounds as a hundred weight and 2,240 pounds as a
ton. The hundredweight of the United States system is 100 pounds and
2,240 pounds is called a long ton. The latter unit is also the gross ton
of maritime commerce, being originally based on an estimate of 12
pounds of container per 100 pounds of commodity.
The apothecaries and troy weight systems should not be used in
entomological work, and fortunately their use elsewhere is dwindling.
Except for the grain, homonymous units in these systems and the avoir-
dupois system are not equal.
The metric ton is sometimes referred to as a millier or a tonneau.




-3-


Units of Mass


U.S. and imperial avoirdupois


1 grain (gr.)

1 dram (dr.)
1 ounce (oz.)
1 pound (lb.)
1 short ton
1 long ton


1/7000 lb.


27.34375 gr.
16 dr.
16 oz.
2000 lb.
2240 lb.


Metric


4


1
64.798918 milligrams(mg.) 164,698.918 micrograms
(4g. or-H
1.7718454grams(g.or gm.) 1,771.8454 mg.
28.349527 g. 28,349.527 mg.
0.4535924277 kilogram (kg.) 453.5924277 g.
0.90718486 metric ton 907.18486 kg.
1.01604704 metric tons 1,016.04704 kg.


4 0 h


0.015432356 gr.
0.5643833 dr.
2.204622341 lb.
1.1023112
short tons


15.432356 gr.
35.27396 oz.
0.9842064
long ton


1mg.
1g.
1 kg.
1 metric ton


1000Ag.
1000 mg.
1000 g.
1000 kg.


CAPACITY LIQUID MEASURE

The units of liquid measure have the same names in both the United States
and the imperial systems. In no case, however, are they equal. The
imperial gallon, quart, and pint are about 20 percent larger, whereas
the imperial fluid dram and fluid ounce are about 4 percent smaller than
the like-named United States units.
At 39.20 F.(40 C.), when it is at maximum density, a United States
gallon of pulre water weighs 8.345 pounds, an imperial gallon 10.022
pounds. At 620F. (16.670 C.) these weights are 8.337 and 10 pounds.
Twelve United States gallons (96 pints) of pure water weigh 100 pounds
(very nearly) and 6 pints weigh 100 ounces (very nearly) at room temper-
ature. The United States gallon is equal to 231 cubic inches and the
imperial gallon to 277.418 cubic inches. There are 7.4805 United States
gallons or 6.229 imperial gallons in 1 cubic foot. The United States
gallon is the old English wine gallon no longer used in the British Empire.
Formerly in chemical and entomological literature the cubic
centimeter (cc.) was commonly used as a misnomer for milliliter (ml.).
Fortunately this is no longer such general practice. 1 milliliter = 1.000028
cubic centimeters; conversely, 1 cubic centimeter = 0.999972 milliliter.
These units are related in the same sense as 231 cubic inches = 1 gallon.
Occasionally the kiloliter is called a stere, but this word properly
refers to the cubic meter.







Units of Capacity Liquid Measure


United States Imperial Metric
,, ,,, ,, ,,Y


1 fluid dram (fl. dr.)


ounce (fl. oz.)


pint (pt.)
quart (qt.)
gallon (gal.)


1/1024 gal.


fl. dr.
fl. oz.
gills
pt.
qt.


1.0408 fl. dr.

1.0408 fl. oz.
0.83268 gill
.83268 pt.
.83268 qt.
.83268 gal.


8.3264 fl. oz.
4.1634 fl. oz.
3.33072 gills
1.66536 pt.
3.33072 qt.


3.69661 milliliters
(ml.)
29.5729 ml.
0.118292 liter (l.)
.473167 1.
.946333 1.
3.785332 1.


3,696.61 microliters
(A -)
29,572 .9 ..
118.292 ml.
473.167 ml.
946.333 ml.
3,785.332 ml.


0.96075 fl. dr. 1 fl. dr. 1/1280 gal. 3.5515 ml. 3,551.5/Il.
.96075 fl. oz. 7.686 fl. dr. 1 fl. oz. 8 fl. dr. 28.412 ml. 28,412.0,l*.
1.20094 gills 4.80376 fl. oz. 1 gill 5 fl. oz. 0.14206 1. 142.06 ml.
1.20094 pt. 4.80376 gills 1 pt. 4 gills .568245 1. 568.245 ml.
1.20094 qt. 2.40188 pt. 1 qt. 2 pt. 1.13649 1. 1,136.49 ml.
1.20094 gal. 4.80376 qt. 1 gal. 4 qt. 4.54596 1. 4,545.96 ml.


0.270518 fl. dr. 0.28157 fl. oz. 1 ml. 100Q0l.
1.05671 qt. 33.8147fl. oz. .8799 qt. 35.196 fl. oz. 1 1. 1000 ml.
264.178 gal. 1,056.71 qt. 219,97554 gal. 879.9 qt. 1 kiloliter(kl.) 1000 1.


fluid
gill




-5-


Equivalents for Teaspoonful, Tablespoonful, and Cup

A measuring cup and measuring spoons, the latter obtainable in nests
of several sizes, are useful for making dilutions under practical con-
ditions where great accuracy is not required. The values given here are
also useful in transposing the precise measurements of the laboratory
into commonly understood units when recommending an insecticide to
dooryard gardeners.
In the absence of suitable scales for weighing, the use of these
volumetric units for measuring powdered insecticides is a common
practice. Tables of equivalents for such use have been published (2).
With the more recently developed wettable powders, however, weight-
volume equivalents of wide application cannot be calculated because of
differences in bulk volume and toxicant content of the numerous products.
The expression "a pint is a pound" is exact for materials with a specific
gravity of 0.96 and approximately true for water or for other materials
with specific gravities near 1, but it is not true for powdered materials
in general. It is suggested that those who wish to use volumetric meas-
urements for powdered insecticidal material should determine the weight
of such quantities as a tablespoonful and a pint, and record these figures
on the packages at hand. Weight dilution directions can then be transposed
to these volumetric units and the equivalents given here employed.

3 teaspoonfuls = 1 tablespoonful 16 tablespoonfuls-
2 tablespoonfuls = 1 fluid ounce 2 gills
16 tablespoonful 1 cup 1/2 pint 1 cup
8 fluid ounces f 8 fluid ounces
237 milliliters
3 teaspoonfuls
1/2 fluid ounce 1 tablespoonful 1 pint
4 fluid drams 1 16 fluid ounces 2 cups
15 milliliters 473 milliliters


CAPACITY DRY MEASURE

In the United States separate systems of capacity units are used for
liquid and dry measure. In the dry-measure system, based on a modern
standard of the Queen Anne bushel of colonial times, the pint and quart
are about 16 percent larger than the units of the same name used in
liquid measure. The pint of this system was originally designed to hold
1 pound of grain, presumably wheat. This relationship is not exact under
present definitions. The United States bushel contains 2,150.42 cubic
inches or 1.244 cubic feet.
The imperial system uses the same pint and quart in both dry and
liquid measures. The imperial gallon may also be used, 8 gallons being
1 bushel. The pint and quart of the United States dry measure system




-6-


are about 3 percent smaller than the imperial units of the same name.
The Winchester bushel, sometimes mentioned in publications from the
British Empire, has the same capacity as the United States bushel. The
imperial bushel contains 2,219 cubic inches or 1.2843 cubic feet.
In the metric system, capacity either liquid or dry, is measured by
the liter and related units.

Units of Capacity Dry Measure


United States Imperial Metric
9 1


1 pint (pt.)

1 quart (qt.)
1peck(pk4


2 pt.
8 pt.


1 bushel(bu414 pk.


0.96895 pt.

.96895 qt.
.96895 pk.

.96895 bu.


1.937 pt.
7.7516 qt.

3.8758 pk.


0.550599 liter(l.)

1.101198 1.
0.880958 deka-
liter (dkl.)
.352383 hecto-
liter (hl.)


550.599 milli-
liters (ml.)
1101.198 ml.
8.80958 1.

3. 52383 dkl.


L.03205 pt. 1 pt. 0.568245 1. 568.245 ml.
1
1.03205 qt. 2.0641 pt. 1 qt. 2 pt. )1.13649 1. 1136.49 ml.
L.03205 pk. 8.2564qt. 1 pk. 8 qt. i0.9092 dkl. 9.092 1.
1.03205 bu. 4.1282 pk. 1 bu. 4 pk. .36368 hl. 3.6368 dkl.



).908102qt. 1.8162 pt. 0.8799 qt. 1.7598 pt. 1 1. 1000 ml.
1.13513 pk. 9.08102 qt. 1.0999 pk. 8.799 qt. 1 dkl. 10 1.
2.8378 bu. 11.3513pk. 2.74975bu. 10.999pk. 1 hi. 10 dkl.


LINEAR, SQUARE, AND CUBIC MEASURE

Except for small differences in standards, the units of linear measure
in the imperial system are the same as those used in the United States and
the same conversion values may be used. It follows that this is likewise
true for the units of area (square measure) and the units of volume (cubic
measure).
Units of linear measure occasionally encountered are the surveyor's
(or Gunter's) link and chain. The link is equal to 7.92 inches, and 100
links, equal to 66 feet, make one chain. The engineer's chain is 100 feet
long, being divided into 1-foot links. The nautical or geographical mile
is equal to 1 minute of arc on a great circle of the earth and equals
6080.2 feet. A fathom used in nautical measurements is equal to 6 feet.


0




-7-


The acre, the basic unit of agricultural area measurements, con-
tains 160 square rods or 10 square surveyor's chains. A square meas-
uring 208.71 feet on each side is approximately 1 acre.
The relationship between the specific gravity of liquids or solids and
cubic measure is of interest. Specific gravity x 1000 equals the weight
in grams of 1 cubic decimeter or (very nearly) the weight in ounces of
1 cubic foot of the material. Since 1 cubic foot equals 7.4805 gallons
(7.5 in round numbers), the weight-volume relationships of liquid or
solid insecticidal materials can be calculated where their specific
gravities are known.

Units of Length


United States and imperial


inch (in.)
foot (ft.)
yard (yd.)
rod (rd.)


1 mile


-

12 in.
3 ft.
16.5 ft.

5,280 ft.


Metric


2.54 centimeters (cm.)
3.048 decimeters (dm.)
0.9144 meter (m.)
.502921 dekameter
(dkm.)
1.6093472 kilometers
(km.)


25.4 mm.
30.48 cm.
9.144 din.
5.02921 m.


1,609. 3472 m.


I I


0.03937 in.
.3937 in.
.3280833 ft.
1.0936111 yd.
1.988384 rd.
0.6213699 mile


3.937 in.
39.37 in.
10.936111 yd.
98.8384 rd.


1


millimeter (mm.)
cm.
dm.
m.
dkm.
km.


1000
10
10
10
10
1000


microns (4)
mm.
cm.
dm.
M.
m.






Units c. Area


United States and imperial


1 square inch(sq. in.)
1 square foot (sq. ft.)
I square yard(sq.yd.)
1 square rod (sq. rd.)
1 acre


144 sq. in.
9 sq. ft.
30.25 sq. yd.
43,560 sq. ft.


6.451626 square centimeters (cm.2)
9.290341 square decimeters (dm.2)
0.8361307 square meter (m.2)
.2529295 are
.404687 hectare (ha.)


645.1626 square millimeters (mm.2)
929.0341 cm2
83.61307 din.2
25.29295 n.2
40.4687 ares


0.15499969 sq. in. 1 cm2 100 rm.2
.1076387 sq. ft. 15.499969 sq. in. 1 din.2 100 Cm.2
1.195985 sq.yd. 10.76387 sq. ft. 1 rn.2 100 din.2
3.95367 sq. rd. 119.5985 sq. yd. 1 are 100 n, 2
2.47104 acres 395.367 sq. rd. 1 ha. 100 ares


Units of Volume

United States and imperial Metric

I cubic inch(cu. in.) 16.387162 cubic centimeters 16,387.162 cubic millimeters
(cm.3 or cc.) (mm.3)
1 cubicfoot(cu. ft.) 1,728 cu. in. 1 28.317016 cubic decimeters(dm.3) 28,317.016 cm.3
1 cubic yard(cu. yd.) 27 cu. ft. 0.7645594 cubic meter (m.3) 764.5594 din.3

0.06102338 cu. in. 1 cm.3 1000 mm.3
.03531445 cu. ft. 61.02338 cu.in. 1 din.3 1000 cm.3
1.3079428 cu. yd. j 35.31445 cu. ft. 1 m.3 1000 dm.3


Metric




-9-


DILUTING INSECTICIDAL CHEMICALS

Equivalent Quantities for Various Quantities of Water

Powdered material. --The quantity of powdered insecticidal chemical
recommended for use in sprays is usually stated in pounds per 50 or 100
gallons of water. Quantities in smaller quantities of water giving the
same concentration as 1 to 5 pounds in 100 gallons are shown in table 1.
Note that the number of pounds per 100 gallons is the same as the
number of ounces per 6 1/4 gallons. This relationship is also true for
50 and 3 1/8 gallons.
Liquid material. --Similar equivalents for use with liquid insecticidal
materials, wetting agents, and the like are also shown in table 1. The
relationship of pounds and ounces noted for powdered material holds
here for pints and fluid ounces.

Concentration on the Basis of Percentage of Toxicant

In the preparation of sprays, dips, or dusts with certain insecticidal
chemicals, the concentration is often based on the percentage by weight
of the toxicant desired in the finished insecticide. The following equations
may be found useful in determining the correct quantity of insecticidal
chemical to use:

Suspensions. --To determine the quantity of insecticidal chemical
necessary for a given percentage of toxicant in the diluted spray, multiply
the number of gallons of spray to be made by 8.345 by the percent of
toxicant desired, and divide by the percent of toxicant in the powdered
material.
Example: 100 gallons of spray containing 0.06 percent of methoxy-
chlor is to be prepared from a wettable powder containing 50 percent of
the toxicant. The quantity of this powder to use is--

100 x8.345x0.06 =
50 1 pound
50

To calculate the quantity of insecticidal chemical in grams, substi-
tute 3,785.3 for 8.345.
The percentages of toxicant in 100 gallons of spray when 1 pound of
wettable powder is used, calculated for powders of eight toxicant levels,
are given in table 2. The quantities of these wettable powders necessary
to give three concentration levels in 100 gallons of spray have also been
calculated. These quantities may be rounded further, if necessary, in
field work.




-10-


Table 1. --Quantities of insecticidal material giving the same concentra-
tion in various quantities of water


Water Insecticidal material


Powder

100 gal. 1 lb. 2 lb. 3 lb. 4 lb. 5 lb.
50 gal. 1/2 lb. 1 lb. 1 1/2 lb. 2 lb. 2 1/2 lb.
25 gal. 4 oz. 8 oz. 12 oz. 1 lb. 1 1/4 lb.
12 1/2 gal. 2 oz. 4 oz. 6 oz. 8 oz. 10 oz.
6 l4 gal. 1 oz. 2 oz. 3 oz. 4 oz. 5 oz.
3 1/8 gal. 1/2 oz. 1 oz. 1 1/2 oz. 2 oz. 2 1/2 oz.
1 gal. 4.5 g. 9.1 g. 13,6 g. 18.1 g. 22.7 g.
1 qt. 1.134 g. 2.268 g. 3.402 g. 4.536 g. 5.670 g.
1 1. 1.198 g. 2.397 g. 3.595 g. 4.793 g. 5.991 g.

Liquid

100 gal. 1/2 pt. 1 pt. 1 qt. 2 qt. 1 gal.
50 gal. 1/4 pt. 1/2 pt. 1 pt. 1 qt. 2 qt.
25 gal. 2 fl. oz. 4 fl. oz. *8 fl. oz. 1 pt. 1 qt.
12 1/2 gal. 1 fl. oz. 2 fl. oz. 4 fl. oz. 8 fl. oz. 1 pt.
6 1/4 gal. 1/2 fl. oz. 1 fl. oz. 2 fl. oz. 4 fl. oz. 8 fl. oz.
3 1/8 gal. 114 fl. oz. 1/2 fl. oz. 1 fl. oz. 2 fl. oz. 4 fl. oz.
1 gal. 2.4 ml. 4.7 ml. 9.5 ml. 18.9 ml. 37.9 ml.
1 qt. 0.591 ml. 1.183 ml. 2.366 ml. 4.732 ml. 9.463 ml.
1 1. 0.625 ml. 1.250 ml. 2.500 ml. 5.000 ml. 10.000 ml.




-11 -


Table 2. --Quantities of wettable powders of different strengths to give
sprays or dips containing three concentrations of the toxicant


Percent of i Pounds to make 100 gallons Percent of toxicant
toxicant in equivalent to 1 pound
wettable powder! 0.25 percent 0.5 percent 1 percent per 100 gallons

20 10.4 20.9 1 41.7 0.024

30 7.0 13.9 27.8 .036
40 5.2 10.4 20.9 .048
50 4.2 8.3 16.7 .06
60 3.5 7.0 13.9 .072
70 3.0 6.0 11.9 .084
80 2.6 5.2 10.4 .096
90 2.3 4.6 9.3 .108


Emulsions and solutions. Diluting by weight. --To determine the
quantity in gallons of an emulsion or solution concentrate to use in
making up a spray containing a given percentage of toxicant by weight,
multiply the number of gallons of spray to be made by the percentage of
toxicant desired, and divide by the percent of toxicant in the concentrate
times its specific gravity.
Example: 100 gallons of spray containing 2 percent of chlordane by
weight is to be prepared from a 40-percent emulsion concentrate having
a specific gravity of 1.02. The amount of the concentrate to use is--

100x2 4.9 gallons
40 x 1.02

Sufficient water is added to make 100 gallons of spray.
For field application, dosages of insecticides are often given in pounds
of toxicant per acre. To determine the weight of toxicant, in pounds, in
1 gallon of emulsion concentrate, multiply 8.345 by the specific gravity
of the concentrate by the percent of toxicant in the concentrate and divide
by 100.
Example: An emulsion concentrate containing 45 percent of chlor-
dane by weight and having a specific gravity of 1.07 is to be used. Each
gallon of the concentrate contains--

8.345 x 1.07 x45 4 pounds of chlordane
100

The quantity of water to be added depends on the method of application.
If 1 pound of chlordane is required per acre, 1 quart of the above

LIBRARY

STATE pLANT BOARD




-12-


concentrate should be used in the quantity of spray that the apparatus at
hand will deliver per acre.
Specific gravity of a product is often unknown to the average user.
These formulas can be used, leaving this factor out, and the results will
be close enough for rough determinations.
Emulsions and solutions. Diluting by parts. --Emulsion and solution
concentrates may be diluted by parts to obtain a desired percentage of
toxicant in the finished spray or dip. It should be borne in mind, how-
ever, that 1 part of insecticidal chemical to so many parts of water is
not the same as in so many parts of finished spray. The difference is
of no great importance in the field use of dilute sprays, but it is of
significance in the formulation of concentrated sprays and, of course,
the distinction is desirable in the interest of precise terminology.
For diluting by parts divide the percent of toxicant in the concentrate
by the percent desired in the finished insecticide. The result is the
number of parts of the finished product that must contain 1 part of the
concentrate. The liquid-capacity measuring unit to be used will depend
on the total quantity of finished insecticide needed.
Example: A dip containing 0.2 percent of toxaphene is desired, and
the concentrate contains 60 percent of the toxicant.

60 t 0.2 = 300

The dilution is therefore 1 part of the concentrate in 300 parts of finished
insecticide or 1 part of the concentrate to 299 parts of water.
To determine the percentage of toxicant in a spray or dip made up on
the basis of parts, divide the percent of toxicant in the concentrate by
the number of parts of the spray.
Example: A spray was made by diluting an extract of pyrethrum
containing 2 percent of total pyrethrins at the rate of 1 part in 400 parts
of spray.
2 400 = 0.005 percent of pyrethrins in the spray

Dusts. --To determine the weight of insecticidal material to use in
preparing a dust containing a given percentage of toxicant, multiply the
percentage of toxicant desired by the pounds of dust to be made and
divide by the percentage of toxicant in the insecticidal material to be
used.
Example: 100 pounds of dust containing 0.5 percent of rotenone is
to be prepared from powdered root containing 4 percent of rotenone.
The quantity of the root necessary is--
0.5x 100 12.5 pounds
4

Then add sufficient dilutent to make 100 pounds.





-13-


The percentage of toxicant in a dust may be determined when the
quantity of insecticidal chemical used and its percentage of toxicant, as
well as the total weight of the prepared dust, are known. Multiply the
number of pounds of insecticidal chemical used by its percentage of toxi-
cant, and divide by the number of pounds of dust prepared.
Example: 20 pounds of a powder containing 10 percent of DDT was
used in making up 100 pounds of dust. The DDT content of the dust was--
20x10- 2 percent
100

Concentration Expressed in Parts per Million

Very dilute concentrations are often expressed in parts per million
(p.p.m.) or as 1 part per stated number of millions, weight per weight
or volume per volume. A list of equivalents is tabulated below.

Parts 1 Part per Parts 1 Part per
per indicated per indicated
million millions million millions

0.001 1000 0.05 20.0
.002 500 .08 12.5
.004 250 .1 10.0
.005 200 .2 5.0
.008 125 .4 2.5
.01 100 .5 2.0
.02 50 .8 1.25
.04 25 1.0 1.0

In United States units 1 ounce in 7,500 gallons (more nearly 7,489.51)
or 1 pound in 120,000 gallons (more nearly 119,832.22) is approximately
1 part per million by weight in water. One fluid ounce in 7,812.5 gallons
is 1 part per million by volume. In metric units 1 part per million may
be expressed as follows: By weight 1 milligram per kilogram, by volume
1 microliter per liter.

DOSAGE EQUIVALENTS AND RELATIONSHIPS

Dusts and Soil Insecticides

The quantities of dust or soil insecticide necessary for large-scale
application, in pounds per acre, may be calculated from the quantities
used in small-scale tests as follows: Multiply the number of grams or
ounces per square foot by 43,560, or per square yard by 4,840, and
divide by 453.59 if the dosage is in grams and by 16 if it is in ounces.





-14-


Example: A dust has been found effective in small-scale tests when
used at the rate of 0.3 gram per square foot. The equivalent dosage per
acre would be--
0.3x43,560 29 pounds
453.59
To determine the number of square feet (or square yards) that 1 pound
of a given material will cover when the dosage per square foot (or square
yard) is known, divide 453.59 by this dosage if it is in grams, and 16 by
this dosage if it is in ounces.
Example: In the dosage of 0.3 gram per square foot mentioned above,
1 pound of the material would cover--
453.59 = 1,512 square feet
0.3
To determine the quantity of material to be used for 1 square foot
when the large-scale dosage is known, multiply the number of pounds per
acre by 453.59 to obtain the number of grams, and by 16 to obtain the
number of ounces, and divide the product by 43,560. For dosages per
square yard divide by 4,840.
Examples: A dosage equivalent to 30 pounds per acre of a given dust
is to be tried on a small scale. The dosage per square foot is--
30 x 453.59 30 x 16
30x = 0.31 gram or 36 = 0.011 ounce
43,560 43,560
Some values that have been worked out for convenient reference are
given in table 3.
Dosages in grams per square foot and pounds per acre are related
approximately as follows: Grams per square foot x 100 = pounds per acre.

Table 3. --Large-scale dosages equivalent to various
small-scale dosages


Dosage perI Square feet that Pounds
square footI 1 pound will cover per acre

Gram
0.1 4,536 9.6
.10413 4,356 10.0
.15619 2,904 15.0
.25 1,814 24.0
.26032 1,742 25.0

Ounce
0.005 3,200 13.61
.008 2,000 21.78
.01 1,600 27.22
.016 1,000 43.56
.025 640 68.06
.064 250 174.24
.16 100 435.6





- 15-


It is frequently desirable to make such conversions on a weight-per-
volume basis. A recent paper by Floyd Smith (7) gives a table for
converting pounds per acre of soil 6 inches deep to equivalent dosages
for various volumes of soil in pots and other containers. His conversion
table is presented in table 4.


Table 4. --Milligrams equivalent to 1 pound per 6-inch acre
in various soil units


Cubic centimeters Equivalent
Soil unit of soil milligrams
per unit

Standard pots:
3-inch 180 0.132
4-inch 500 .368
5-inch 900 .662
6-inch 1,500 1.103
7-inch 2,400 1.765
8-inch 3,785 2.784
Short pot, 8-inch 2,900 2.133
Pan, 8-inch 1,400 1.030
Liter 1,000 .735
Gallon 3,785 2.784
Cubic foot 28,317 20.826
Bushel 35,238 25.916





-16-


Weight-Volume Relationships in Dosage Estimation

Surface application. --Dosage of residual insecticides for surface
application are often given in milligrams of toxicant per square foot.
If the percentage by weight of toxicant and the specific gravity of the
spray are known, the approximate number of square feet that 1 gallon
will cover at a stated dosage can be estimated by use of table 5. Select
the factor opposite the dosage required and under the specific gravity of
the spray at hand. Multiply this factor by the percentage of toxicant in
the spray. Water suspensions of wettable powder may be regarded as
having a specificc gravity of 1.
Exa i, le: We wish to estimate the approximate number of square
feet that 1 gallon of 5-percent DDT solution will cover at a dosage of
150 milligrams per square foot. The specific gravity of the oil solution
is about 0.8. The factor 200 is read from table 5 and the calculation
made as follows: 200 x.5 = 1000 square feet.

Field application. --Dosage in milligrams per square foot is approxi-
mately one-tenth the dosage in pounds per acre. The dosage figures in
table 5 can therefore be read as pounds per acre by pointing off one
place. To estimate the gallonage of spray required to produce a stated
dosage in pounds of toxicant per acre, divide 45,300 by the selected
factor in table 5 times the percent of toxicant in the spray.
Example: A dosage of 2.5 pounds of DDT per acre is to be applied
by airplane. The oil solution to be used contains 10 percent of DDT and
has a specific gravity of 0.9.
45,300
130x0 3.33 gallons per acre
1360x 10

Table 5 --Factors for use in estimating surface coverage of
residual formulations and gallonage per acre


Dosage, Specific gravity
(mg. per sq. ft.) I II


10 3000 3400 3800 4200
25 1200 1360 1520 1680
50 600 680 760 840
75 400 453 506 560
100 300 340 380 420
150 200 227 253 280
200 150 170 190 210





-17-


Dosage Estimates for Row Crops

Equivalent dosages for certain acre rates and the areas or feet of
row of three different spacings that 1 gallon of spray or 1 pound of dust
will cover are given in table 6. Estimates of the requirements for areas
less than an acre can be made from these figures.

Table 6. --Dosages for row crops equivalent to various dosages per acre

1 Gallon or 1 pound will cover

Rate per acre Feet of row with spacing between rows of
Square feet i ......
2 1/2 feet 3 feet T3 1/2 feet


Sprays
Gallons
5 8,712 3,485 2,904 2,489
10 4,356 1,742 1,452 1,245
25 1,742 697 581 498
50 871 348 290 249
75 581 232 194 266
100 436 174 145 125
200 218 87 73 62

Dusts
Pounds
5 8,712 3,485 2,904 2, 489
10 4,356 1,742 1,452 1,245
15 2,904 1,162 968 830
20 2,178 871 726 622
25 1,742 697 581 498
50 871 348 290 249


FUMIGATION

Dosages of fumigants are commonly given in ounces or pounds per
1000 cubic feet. Metric equivalents may be calculated on the basis of the
following relationship:
1 poundper 1000 cubic feet = 16.01894 milligrams per cubic decimeter
or
Milligrams per cubic decimeter =
1.00118= ounces per 1000 cubic feet
1.00118

Thus milligrams per cubic decimeter is approximately equal to ounces per
1000 cubic feet.





-18-


This relationship is of value in transposing laboratory dosages to
conventional units for large-scale work and in determining the concen-
tration of a fumigant, within a fumigation chamber, after proper chemical
analysis of aspirated quantitative samples.
Other conversion values for gas concentrations that may be of value
in fumigation studies are as follows:

1 cubic millimeter per cubic decimeter (liter) = 1 part per million
by volume
1 percent by volume = 10,000 parts per million
Low concentrations of fumigants or vapors in the air, where the
concentration in milligrams per cubic decimeter (liter) is determined,
sometimes are expressed directly as parts per million--i. e., parts by
weight to a million parts by volume. Unless it is clearly explained,
such use of the expression "parts per million" is best avoided, that
statement being reserved for ratios of weight to weight or of volume to
volume.
The conversion of any weight-per-unit-volume ratio to a volume-
per-unit-volume ratio, such as parts of vaporized fumigant per million
parts of air, involves an understanding of the gram-molecular volume
relationship. This may be stated as follows: The volume of a gram-
molecule of a gas at 0oC. and 760 mm. of mercury is equal to 22.4
liters. At 250 C. and 760 mm. of mercury the volume is 24.45 liters
or 24,450 milliliters. The latter figures approximate the conditions
encountered in practical fumigation work. Conversion formulas based
on these figures are as follows:
24,450 x milligrams per cubic decimeter
moleclar.wight= parts per million
molecular weight

Parts per million x molecular weight = milligrams per cubic
24,450 decimeter

Example: A concentration of lindane vapor of 0.0006 milligram per
cubic decimeter has caused high mortality of house flies. The molecular
weight of this material is 290.85. The concentration may be expressed
in parts per million by volume as follows:
24450 x 0.0006
245 x 0...= 0.05 p.p.m., which is equivalent to 1 part in
290.85 20 million

Certain physical constants for a group of common fumigants are
presented in table 7. The figures for milliliters per pound and per
gallon have been rounded. Precise figures may be obtained by use of
the specific gravity.





-19-


Table 7. --Physical constants for several common fumigants

Boiling M Specific Pounds
Fumigant point Mgravity at per
oc. weight j200/40 C. per poud
gallon


Acrylonitrile 78 53.06 0.797 569 6.7
Carbon disulfide 46.3 76.13 1.263 359 10.5
Carbon tetrachloride 76.8 153.84 1.595 284 13.3
Chloropicrin 112 164.39 1.651 275 13.8
Dichloroethyl ether 178 143.02 1.222 371 10.2
Ethylene dibromide 131.6 187.88 2.180 208 18.2
Ethylene dichloride 83.7 98.97 1.257 361 10.5
Ethylene oxide 10.7 44.05 0.887(10o/49 511 7.4
Hydrocyanic acid 26 27.03 0.688 659 5.7
Methyl bromide 4.6 94.95 1.732(00/40) 262 14.4
Trichloroethylene 87 131.40 1.477 307 12.3


MISCELLANEOUS

Capacity of Sprayer Tank

The capacity, in gallons, of the tanks on sprayers may be calculated
as follows:

Cylindrical tanks: Multiply length by square of the diameter, in
inches, by 0.0034.
Rectangular tank: Multiply length by width by depth, in inches, by
0.004329.
Tanks with elliptical cross section: Multiply length by short diameter
by long diameter, in inches, by 0.0034.

Diluting Miscible Liquids by Volume

Commercial grain alcohol of known percentage concentration can
be diluted as follows: Into a 100-ml. graduate pour as many milliliters
of the stronger solution as the percentage required in the weaker. Then
add water until the mixture reaches the milliliter mark equivalent to the
percentage of the stronger solution.
Example: To make 70-percent from 95-percent alcohol, pour into
the graduate 70 ml. of the 95-percent solution and fill to the 95-ml.
mark with water. The result is 95 ml. of a 70-percent solution.
The same procedure can be used for any other liquid, such as
acetone, that is miscible with water, and in fact for any pair of miscible
liquids.





-20-


Temperature Conversion

The two most commonly used thermometric systems are Centigrade
(C.) and Fahrenheit (F.). Equivalents for the two scales may be calculated
as follows:
0C. = (OF. 32) x 0.5556
OF. = (0C. xl.8) + 32

A number of equivalents for the two scales are presented below:


0 F. oC.


-17.78
-12.22
-10
- 6.67
- 1.11
0
4.44
10
15.56
20
21.11


0 F.


80
86
90
100
104
110
120
122
130
140
150


0 C.

26.67
30
32.22
37.78
40
43.33
48.89
50
54.44
60
65.56


0F.

158
160
170
176
180
190
194
200
210
212


0oc.

70
71.11
76.67
80
82.22
87.78
90
93.33
98.89
100


LITERATURE CITED


(1) Bearce,


Henry W.


1936. United States and British units of weights and measures.
Sci. Monthly 43: 566-568.


(2) Howard,
1945.


N. F., Weigel, C. A., Smith, C. M., and Steiner, L. F.
Insecticides and equipment for controlling insects on
fruits and vegetables. Rev. U.S. Dept. Agr. Misc.
Pub. 526, 56 pp.


(3) Irwin, K. G.
1951. Fathoms and feet, acres and tons: An appraisal.
Monthly 72(1): 9-17.


Sci.


(4) National Bureau of Standards
1936. Units of weight and measure (United States customary
and metric). Definitions and tables of equivalents.
E. S. National Bur. Standards, Misco Pub. M 121,
68 pp.





-21 -


(5) National
1920.


(6) National
1926.


Bureau of Standards
Household weights and measures. U. S. Bur. Standards,
Misc. Pub. 39, 2 pp.

Research Council
International critical tables of numerical data, physics,
chemistry and technology. v. 1, pp. 1-15. New York.


(7) Smith, Floyd F.
1952. Conversion of per-acre dosages of soil insecticide to
equivalents for small units. Jour. Econ. Ent. 45:
339-340.





UNIVERSITY OF FLORIDA

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