• TABLE OF CONTENTS
HIDE
 Front Cover
 Acknowledgement
 Control methods
 Sumersed weeds
 Floating weeds
 Ditchbank grasses, other aquatic...
 Care of sprayers
 Suggested control measures for...
 Calculations for amount of material...






Group Title: Circular - Agricultural Extension Service, University of Florida - 219
Title: Aquatic weed control
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067879/00001
 Material Information
Title: Aquatic weed control
Series Title: Florida. University, Gainesville. Agricultural Extension Service, Circular 219
Physical Description: 16 p. : tables. ;
Language: English
Creator: Harrison, D. S
Publisher: University of Florida, Agricultural Extension Service
Place of Publication: Gainesville
Publication Date: 1962
 Subjects
Subject: Aquatic weeds -- Control   ( lcsh )
Aquatic weed control -- Florida   ( lcsh )
Genre: non-fiction   ( marcgt )
 Notes
Statement of Responsibility: D.S. Harrison.
General Note: Cover title.
General Note: "January 1962."
Funding: Circular (Florida Cooperative Extension Service) ;
 Record Information
Bibliographic ID: UF00067879
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 19595932

Table of Contents
    Front Cover
        Page 1
    Acknowledgement
        Page 2
    Control methods
        Page 3
    Sumersed weeds
        Page 4
    Floating weeds
        Page 5
    Ditchbank grasses, other aquatic weeds, and prayers for applying herbicides
        Page 6
    Care of sprayers
        Page 7
    Suggested control measures for common aquatic weeds of Florida
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Calculations for amount of material required
        Page 15
        Page 16
Full Text


AQUATIC
Weed Control
D. S. HARRISON


UNIVERSITY OF FLORIDA AGRICULTURAL EXTENSION SERVICE
CIRCULAR 219 0 Gainesville, Florida 0 JANUARY 1962


61












Authors of this circular are D. S. Harrison, associate agricul-
tural engineer, Agricultural Extension Service; R. D. Blackman,
research agronomist, Agricultural Research Service, USDA; D.
W. Kretchman, assistant horticulturist, Florida Agricultural Ex-
periment Stations; J. R. Orsenigo, associate horticulturist, Flor-
ida Agricultural Experiment Stations; D. E. Seaman, plant physi-
ologist, Agricultural Research Service, USDA; and L. W. Weldon,
research agronomist, Agricultural Research Service, USDA.









ACKNOWLEDGMENTS
This publication is based on the results of latest research on
aquatic and ditchbank weed control by the Florida Agricultural
Experiment Stations and the U. S. Department of Agriculture.
The information was compiled by the Florida Agricultural Ex-
tension Service.
The authors are grateful for the contributions, suggestions
and review by E. G. Rodgers, Merrill Wilcox and W. T. Scudder,
Florida Agricultural Experiment Stations, and John C. Stephens,
Agricultural Research Service, USDA.

Printed January 1962









COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and United States Department of Agriculture, Cooperating
M. O. Watkins, Director










AQUATIC WEED CONTROL

IN PONDS, DITCHES, CANALS AND STREAMS

Obnoxious aquatic plants which confront the user of water in
canals, ditches, ponds, streams, and reservoirs may be classified
into three broad groups based upon the plant's growth habit.
These are floating, emersed and submersed.
Floating aquatic plants are completely free, or floating in
the water, and not rooted in the soil. Examples of the more com-
mon of these troublesome plants are waterhyacinth, water let-
tuce and water fern.
Emersed aquatic plants are rooted in soil below the water sur-
face. They grow up through the water, with a major portion of
the plant above the water surface. Examples of emersed aquatic
plants are cattail, maidencane, cutgrass, spatterdock, waterlily,
sawgrass, smartweed, rush, pickerel weed, and water primrose
or primrose willow.
Submersed aquatics may or may not be rooted on the bottom.
They grow entirely beneath the surface of the water. This group
of pest plants probably causes the most serious weed problem
in drainage and irrigation channels and ponds. These weeds
may retard the flow of water by as much as 90 percent in some
areas of the state. Examples of the more common submersed
aquatics are southern naiad or head wool, coontail, bladderwort,
algae and certain sedges.

CONTROL METHODS
Special dragline buckets such as the hyacinth bucket are
effective in removing submersed and floating water weeds. How-
ever, the few plants remaining after removal will spread, mak-
ing an annual maintenance program necessary. Another method
of removing submersed and floating weeds is by dragging chains
down the channel and then pumping the refuse into a reservoir.
Boats equipped with power-driven cutters have been somewhat
effective in the south on cattails, rushes, sawgrass and tule, but
rather ineffective on other plants. Underwater mowing must be
done repeatedly to obtain control. The cutter bar is operated
12 to 60 inches below the water surface, and the plant growth
3








is mowed at that depth three to five times during a growing
season.
All of the above methods are generally more expensive and
often less effective than chemical control. The proper chemicals,
in combination with the right method of application, must be
used to obtain most effective control of aquatic weeds and
grasses. The following discussion and the table of recommenda-
tions in the Appendix are devoted to the more recent research
findings for chemical control of aquatic and ditchbank weeds
found in Florida.

SUBMERSED WEEDS
Most submersed aquatics can be successfully controlled with
emulsifiable solvents, acrolein or sodium arsenite. Submersed
aquatic weeds can be controlled by chemicals at a cost of one-
third to one-fourth that obtained with mechanical means. The
control also lasts for longer periods.
Only aromatic and some other unsaturated hydrocarbons are
satisfactory solvents for control of submersed weeds. Emulsi-
fiers must be added to the solvents at a volumetric concentration
of 21/2 percent. This is 21/ gallons of emulsifier per 100 gallons
of solvent. Commercially available preparations already have
the emulsifier added. Diesel oil, kerosene, mineral spirits, tractor
distillates and similar aliphatic materials do not control sub-
mersed water weeds. For directions on mixing weed-killing
chemicals, see Florida Agricultural Experiment Station Cir-
cular S-97.
In drainage ditches in sandy soils, where there is considerable
seepage and velocity, apply solvents at 80 parts per million by
volume for best control. On the organic soils, complete control
may be obtained with 20 parts per million by volume.
Because of fire hazard resulting from low flash point of the
solvents, make application under or directly on top of the water,
and with the use of carbon dioxide as a propellant rather than
positive displacement pumps. Pressure must be adequate-30
to 40 pounds per square inch. The spray nozzle should be suffi-
ciently small to give good mixing of the chemical in the water.
A wetting agent may be necessary to obtain adequate wetting
of emersed and floating weeds and satisfactory kill when using
certain aqueous sprays.
Sodium arsenite and acrolein are two other materials that
give satisfactory control of submersed aquatics. Effective con-
4








trol has been obtained by using sodium arsenite (40 percent
As203) at rates of four parts per million by volume. When using
60 percent As203, the rates to be used are even less. Use EX-
TREME CAUTION when applying sodium arsenite; it is toxic
to humans and animals. However, it is not toxic to fish at rates
of three to five parts per million by volume.
A new material, acrolein, has also been effective against sub-
mersed aquatics at rates as low as three to six parts per million.
Control may last from three months to one year. Acrolein has
been more effective than the aromatic solvents when applied in
comparable situations but is only available through custom ap-
plication at this time.
Certain algae may be controlled with bluestone (copper sul-
fate) at eight pounds per one million gallons of water.
Amount of Material Required.-Formulas given on page 15
show how to calculate the amount of material required for a par-
ticular application.
Water Control for Best Results.-Proper water control is vital
for best results in using herbicides for submersed aquatics.
The water level in the canal or pond should be normal or just
high enough to cover the weeds. The herbicide must contact
all plants to kill them. The water in the canal, ditch or pond
should be controlled with little or no flow for at least 24 and
preferably 48 hours after treatment. This allows the herbicide
sufficient contact time for good penetration and kill of the plants.

FLOATING WEEDS
The most common of these is waterhyacinth. Waterhyacinth
is most economically controlled with an amine formulation of
2,4-D. Low volatile esters, such as propylene glycol butyl ether
and butoxy ethanol esters, also give good control. These esters
are more volatile than the amine salt formulations and should
not be used in areas where there is any possible danger of drift
of volatilized fumes. Highly volatile esters of 2,4-D should not
be used. Waterhyacinth is killed more rapily in warm weather
than in cooler weather. A poor kill may result if rain occurs
soon after treatment.
Rates of 2,4-D as low as one to two pounds acid equivalent
per acre have been used to control waterhyacinth; however, to
obtain 100 percent control, the use of at least four to eight pounds
per acre of amine salt or low volatile ester is recommended.
Apply the spray at a rate of 100 to 200 gallons per acre to wet
5








the foliage thoroughly. It is generally more efficient if the area
is patrolled periodically, spot-treating small patches of water-
hyacinth, rather than waiting for the problem to become severe
before retreatment.
Complete removal of floating aquatic weeds may encourage
growth of submersed weeds, and measures should be taken to
prevent or control subsequent infestations of submersed weeds
by the methods described above.

DITCHBANK GRASSES
Paragrass, napiergrass and certain other perennial grasses
along ditchbanks may be controlled with 5 to 10 pounds per acre
of dalapon per application in 50 to 100 gallons per acre of water.
Apply two to three times at intervals of one to two weeks be-
tween applications. The use of a wetting agent is helpful.
When grasses, broadleaf weeds, and woody plants or brush
are growing in combination, 2,4-D and 2,4,5-T at two to four
pounds per acre can be included with the first application of dala-
pon, and this mixture will give effective control of all three types
of weeds.
OTHER AQUATIC WEEDS
Alligatorweed was first reported in the United States as
early as 1897. Only recently, however, has it been observed to
cause serious difficulty in Florida. This plant is particularly dan-
gerous, since it is capable of growing rooted or free-floating in
water and it may also invade nearby croplands.
Repeated applications of weighted emulsions of 2,4-D at six
to eight pounds per acre have given fair control of alligatorweed
above the water. At the present time, the frequent use of 2,4-D
or silvex offers the best control.
Other emergent weeds which cause difficulty in moving water
through drainage and irrigation channels are spatterdock, pick-
erelweed, cattails, waterprimrose and certain brush species. Con-
trols are listed on pages 11-14.

SPRAYERS FOR APPLYING HERBICIDES
Space does not permit a complete description of all the spray-
ers used to apply aquatic herbicides. Instead, a few of the more
common ones used in Florida will be mentioned. These are com-
pressed air sprayers and portable tractor or boat sprayers.
For treating large areas of ditches and ditchbanks, the trac-








tor-mounted or trail-behind sprayer with handgun or portable
boat-type sprayer is the most economical to use. These rigs are
either power-take-off or auxiliary-engine operated.
The most common pumps used are nylon roller, gear or piston
type. Rotary pumps with Ni-Resist cases and nylon rollers have
much more resistance to wear than other type rotary pumps
when spraying with wettable powder herbicides. Piston type
pumps specifically designed for weed control are also satisfactory.
Pumps should have 30 to 50 percent more capacity than that
required for the boom output to provide for by-pass agitation,
unless agitation is otherwise provided.
A popular rig in southern Florida for treating large areas of
ditches or ditchbanks consists of a portable sprayer and tank
which may be transported and used in a boat. The pump is
powered by an air-cooled engine, and a 30 to 55 gallon drum is
used as a supply tank. A single hose connected to the outlet side
of the pump runs to a handgun having single or multiple nozzles.
A diaphragm or spring-loaded regulator is used so pressures may
be increased or decreased as needed. For spraying above the
ground or water, use pressures in the range of 25 to 400 pounds
per square inch.

CARE OF SPRAYERS
Clean the sprayer thoroughly after each spraying operation,
since many herbicides are corrosive and may cause rust to form
in addition to damaging parts of the pump, pressure regulator
and nozzles.
When 2,4-D esters or oil soluble materials have been used:
1. Rinse the sprayer system with kerosene.
2. Add one to two pounds of washing soda or one quart of
household ammonia to 30 gallons of water.
3. Allow this to remain in the sprayer for several minutes,
start the sprayer and circulate it through the system.
4. Rinse the sprayer with six to eight ounces of liquid deter-
gent in 30 gallons of water and drain.
5. Rinse the sprayer again with water and drain.
When 2,4-D amine or other water soluble salts have been used:
1. Rinse the sprayer system with either one to two pounds
of washing soda or 1 quart of household ammonia in 30
gallons of water.
2. Allow the solution to stand in the sprayer for several








minutes; start the pump and circulate it through the
system.
3. Drain the sprayer.
4. Rinse the sprayer system with six to eight ounces of
liquid detergent in 30 gallons of water and drain.
5. Rinse the sprayer system with water and drain.
To prevent rust or corrosion, flush the sprayer system by
pumping through a solution of automobile radiator rust inhibitor
in water (1/2 cup per gallon of water) and drain. Kerosene or
fuel oil will not prevent rust or corrosion.

SUGGESTED CONTROL MEASURES
FOR COMMON AQUATIC WEEDS OF FLORIDA
The following table is based mainly on aquatic weed-control
investigations in Florida. Recommended control measures are
listed, when available, with the notation "R". Suggested ma-
terials "S" and new materials which have shown promise in pre-
liminary tests "P" are also listed. Where control information
is limited or not available, no "R" rating is given, but meas-
ures thought likely to give fair to good control are suggested.
Only commercially-available herbicides are either recommended
or suggested for use. Many of the new chemicals rated as "prom-
ising" are not available at present.
This information is provided for the benefit of those who are
informed about the general nature and use of herbicides, and
are familiar with the equipment and techniques employed in
the application of such chemicals. Space does not permit a full
discussion of the properties of the herbicides mentioned, so users
are advised to read package labels carefully and to heed all di-
rections and precautions. Persons who are not familiar with
herbicides and their use should seek competent advice before
proceeding with any of the control measures suggested in this
circular.
The information given in recommendations for control is
a compilation of data, the interpretation of which may be modi-
fied with additional experimentation.







SUGGESTED CONTROL MEASURES FOR COMMON AQUATIC WEEDS OF FLORIDA

Weed Control Information

SUBMERSED WEEDS Status* Herbicide** Rate of Remarks
Application Remarkst

bladderwort R acrolein 5 ppmv Inject underwater.
(Utricularia spp.) R aromatic solvents & 20-80 ppmv Inject underwater.
chlorinated benzenes

S As2Os (sodium arsenite) 4 ppmw Poisonous-Follow directions!
Inject underwater.
S silvex (low-volatile esters) 2 ppmw Inject in ponds or small lakes.
P diquat 5 ppmw Inject underwater.
coontail R,S,P Same as for bladderwort
(Ceratophyllum S endothal 5-10 ppmw Inject in ponds or small lakes.
demersum L.) P endothal (TD 47) 3-5 ppmw Inject in ponds or small lakes.
elodea R,S,P Same as for bladderwort
(Elodea canadensis, P endothal (TD 47) 3-5 ppmw Inject in ponds or small lakes.
Michx., Elodea densa,
(Planch.) Caspary)
naiad, southern R,S,P Same as for bladderwort
(Najas guadalupensis S endothal 3-5 ppmw Inject in ponds or small lakes.
(Spreng.) Magnus) S 2,4-D(granular) 20-40 lb/A Broadcast over still water.
P endothal (TD 47) 3-5 ppmw Inject underwater.
P silvex (granular) 20-40 lb/A Broadcast over water surface.
Status: R Recommended for satisfactory control.
S Suggested for possible or partial control.
P Promising herbicide under investigation but not recommended pending further evaluation.
** Herbicides referred to by common name. Chemical name listed on pages 15 and 16.
t Abbreviations used listed on page 16.









Weed Status Herbicide Rate Remarks

pondweed R,S,P Same as for bladderwort
(Potamogeton spp.) I S endothal 3-5 ppmw Inject in ponds or small lakes.
wildcelery
(Vallisneria spp.) S silvex (low-volatile esters) 2 ppmw Inject in ponds or small lakes.

FLOATING WEEDS
duckweed |
(Spirodela polyrhiza S 2,4-D (low-volatile esters) 2-4 lb/A Spray on foliage in fuel oil at 20
(L.) Schleid; Lemna gpa.
minor L.; Wolffa spp.) S diesel oil (emulsifiable) 20-50 gpa Spray in hot weather.
P diquat 1-3 Ib/A Add 0.1% v/v surfactant.
or 1-3 ppmw Inject underwater.
floating fern
(Ceratopteris S 2,4-D(low-volatile esters) 4-8 lb/A Spray in fuel oil at 50-100 gpa.
pteridoides (Hook.)
Underw.)
waterfern R 2,4,5-T, water-in-oil 4-6 lb/A Check oil:water recipe.
(Salvinia "invert" emulsions
rotundifolia Willd.) P 2,4-D, water-in-oil 4-6 lb/A Check oil:water recipe.
"invert" emulsions
P diquat 2-3 lb/A In water + 0.1% v/v surfactant.
waterhyacinth R 2,4-D (amine salts) 2-4 lb/A Spray in water at 100-200 gpa.
(Eichhornia crassipes R 2,4-D (low-volatile esters) 2-4 lb/A In water or fuel oil to cover.
(Mart.) Solms.) S amitrole-T 1-2 lb/A In water at 200 gpa.
P diquat 1-3 lb/A In water + 0.1% v/v surfactant.
waterlettuce S 2,4-D (low-volatile esters) 4-8 lb/A Spray in water or fuel oil at 100-
(Pistia stratiotes L.) 200 gpa.
S MCPA (alkali or amine salts) 4-6 lb/A In water + 0.1% v/v surfactant.
P diquat 2-4 lb/A In water + 0.1% v/v surfactant.







Weed Status Herbicide Rate Remarks

EMERSED WEEDS
alligatorweed
(Alternanthera S 2-4-D(amine salts or 4-8 lb/A In water at 100-200 gpa.
philoxeroides (Mart.) low-volatile esters) Repeat frequently.
Griseb.)
P silvex (low-volatile esters) + 8 lb/A Emulsifiable mixture with sp. gr.
aromatic solvents + 1.003, spray in water at 200
chlorinated benzenes gpa.
P silvex (granular) 20-40 lb/A Broadcast over weeds in rooted-
emersed habitat.
arrowhead
(Sagittaria spp.) S 2,4-D (low-volatile esters) 4-8 lb/A Spray in water or fuel oil to cover.
S silvex (low-volatile esters) 4-8 lb/A In water or fuel oil to cover.
bulrush
(Scirpus spp.) S 2,4-D (low-volatile esters) 4-8 lb/A In water or fuel oil to cover.
cattail R dalapon 15-20 lb/A Spray in water at 200 gpa.
(Typha spp.) R dalapon + 5-10 lb/A In water at 200 gpa.
diesel oil (emulsifiable) 10 gpa
S dalapon + 5 lb/A In water at 200 gpa.
amitrole-T or amitrole 3 lb/A
P amitrole-T 4 lb/A In water at 200 gpa; 2 applications,
1 mo. apart.
lizardtail
(Saururus cernuus L.) S 2,4-D (volatile esters) 4-8 lb/A Spray in fuel oil to cover.
Hazardous near crops.
lotus, American
(Nelumbo lutea (Willd.) S 2,4-D (amine salts) 2-6 lb/A In water to cover-use 0.05-0.1%
Pers.) v/v surfactant.
S 2,4-D (low-volatile esters) 2-4 lb/A In fuel oil to cover.











Weed Status Herbicide Rate Remarks

parrotfeather
(Myriophyllum S 2,4-D (low-volatile esters) 4-8 lb/A Spray to wet emersed foliage.
brasiliense Camb.) S silvex (low-volatile esters) 1-2 ppmw Inject into water.
pennywort, water
(Hydrocotyle spp.) S Same as for American lotus
pickerelweed
(Pontederiac S silvex (low-volatile esters) 4-8 lb/A In water at 100-200 gpa.
cordata L.) P silver (granular) 20-40 lb/A Broadcast over weed stand.
primrosewillow R 2,4-D (amine salts) 2-6 lb/A Spray to wet thoroughly.
(Jussiaea peruviana L.) S 2,4,5-T (amine salts) 4-6 lb/A Wet thoroughly.
P 2,4-D (water-in-oil "invert" 4-6 lb/A Check water:oil recipe.
emulsion)
rush
(Juncus spp.) S silvex (low-volatile esters) 4-8 lb/A In water or fuel oil to cover.
sawgrass R Underwater mowing.
(Cladium jamaicense S dalapon + 10-20 lb/A Spray in water at 200 gpa.
Crantz) diesel oil (emulsifiable) 10 gpa
smartweed
(Polygonum spp.) S 2,4-D(low-volatile esters) 4-8 lb/A In fuel oil at 100 gpa.
P amitrole-T 1-2 lb/A In water at 100-200 gpa.
spatterdock
(Nuphar advent (Ait.) Aitf.) S 2,4-D (granular) 20-40 lb/A Broadcast.
S silvex (low-volatile esters) 1-2 ppmw Inject in ponds or small lakes.
P silvex (granular) 20-40 Ib/A Broadcast.
spikerush silver
(Eleocharis spp.) S silvex (low-volatile esters) 4-8 lb/A In water or fuel oil to cover.







Weed Status Herbicide Rate Remarks

waterlily
(Nymphaea spp.) S 2,4-D (low-volatile esters) 4-6 lb/A In water or fuel oil to cover-
repeat frequently.
S 2,4-D (granular) 20-40 lb/A Broadcast over still water sites.
S silvex (low-volatile esters) 1-2 ppmw Inject in ponds or small lakes.

AQUATIC AND DITCHBANK GRASSES
cutgrass, southern
(Leersia hexandra Sw.) S dalapon 4-5 lb/A 3 spray applications, 1 wk. apart.
floating-grass
(Paspalum fluitans S dalapon 5-10 lb/A Use 0.05-0.1% v/v surfactant.
(Ell.) Kunth)
jaragua
(Hyparrhenia rufa (Nees) R dalapon 5-7.5 lb/A 2-3 applications, 1 wk. apart.
Stapf.)


knotgrass
(Paspalum distichum L.) S
maidencane
(Panicum hemitomon S
Schult.)
paragrass R
(Panicum purpurascens S
Raddi) S
recd, common

Trin.)
S


dalapon

dalapon

dalapon
dalapon
diuron

dalapon

dalapon +
amitrole


5-10 lb/A

15-30 lb/A

5-10 lb/A
10-15 lb/A
10-20 lb/A

25-30 lb/A

15-20 lb/A
2-5 lb/A


Use 0.05-0.1% v/v surfactant.

Spray in water to cover.
Resistant when flooded.
3 applications, at 2-3 wks. apart.
Repeat 2-3 month intervals.
Spray in water on ditchbanks.

Spray foliage at pre-flowering
stage.
In water at 200-400 gpa.


0r3













Weed Status Herbicide

watergrass, southern
(Hydrochloa caroliniensis S
Beauv.)

OTHER DITCHBANK BRUSH AND TREES

castorbean R 2,4,5-T
(Ricinus communis L.)
guava, common R 2,4,5-T
(Psidium guajava Raddi.)
R fenuron
pepper tree, Brazilian R 2,4,5-T
(Schinus terrebinthifolius)
R 2,4,5-T
(ester form)
pine, Australian R 2,4-D or
(Casuarina equisetifolia 2,4,5-T
Forst.)
R Sodium Arsenite


seamyrtle R Ifenuron
(Baccharis halimifolia L.) I


Rate







4-lb/A

Same as for
Brazilian
pepper tree
20 lb/A
4 lb/A

16 lb/100 gal
oil
16 lb/100 gal
oil

2 lb. As2Os
equiv. per
1 gal. water
20 lb/A


Remarks


Underwater mowing.
Resistant to herbicides.



Spray plants when small or treat
resprouts from stumps.



Very toxic to all plants.
Spray entire plant or re-sprouted
stumps.
Cut down tree and paint stump.
Use as a frill or stump treatment.

Make a cup or frill around tree at
2 to 3 feet above ground-fill
cup with solution.
Very toxic to all plants.


--


---








CALCULATIONS FOR AMOUNT OF MATERIAL REQUIRED
The following formulas may be used to compute the amount of herbi-
cide required to obtain a desired final concentration in the water of a ditch
or canal:
1. Concentration based on parts per million by volume (ppmv).
V=AxLxCx 7.5

1,000,000
V = number of gallons of herbicide required; A = cross-section
area of channel in square feet; L = length of channel in feet;
C = desired final concentration of herbicide in ppmv.
2. Concentration based on parts per million by weight (ppmw).
W=AxLxCx 62.5

1,000,000
W = number of pounds of herbicide required'; A = cross-section
area of channel in square feet; L = length of channel in feet; C=
desired final concentration of herbicide in ppmw.
The following formulas may be used to compute the amount of herbi-
cide required to obtain a desired final concentration in the water of a pond
or lake:
1. Concentration based on parts per million by volume (ppmv).
V = Ax D x Cx 0.33
V = number of gallons of herbicide required; A = area of the
water surface in acres; D = average depth of the pond or lake in
feet; C = desired final concentration of herbicide in ppmv.
2. Concentration based on parts per million by weight (ppmw).
W =Ax D x C x 2.72
W = number of pounds of herbicide required'; A = area of the
water surface in acres; D = average depth of the pond or lake in
feet; C = desired final concentration of herbicide in ppmw.

1For liquid herbicide formulations with active-ingredient or acid-equiv-
alent concentrations given in pounds per gallon, the number of pounds of
herbicide required may be divided by the pounds per gallon to obtain the
number of gallons of herbicide formulations required.

LIST OF HERBICIDES

Common Name Chemical Name or Description
acrolein.................................... ....................... acrylaldehyde
am itrole................................ ........ ............... 3-am ino-1,2,4-triazole
amitrole-T......-............. .....................3.... -amino-1,2,4-triazole +
ammonium thiocyanate
aromatic solvents + chlorinated benzenes.....emulsifiable mixtures of xylene-
type solvents + polychloro-
benzene
As20------..................................sodium arsenite expressed as
arsenic trioxide
dalapon.......................-------------------2,2-dichloropropionic acid
diquat ................- -- .........-- -------- 1:l'-ethylene-2:2'-dipyridylium
dibromide
diuron.............--.........-- ............ 3-(3,4-dichlorophenyl)-1,1-
dimethylurea









endothal....................--------............................- sodium salt of 3,6-endoxyhexa-
hydrophthalic acid
TD-47......--------...................................... ---di-N.N dimethylcocoamine salt
of endoxyhexahydrophthalic
acid
fuel oil-.............-----....................- ......-- ............-kerosene or No. 2 diesel oil will
suffice
emulsifiable -..........-----.........--.....fuel oil containing 1-5% v/v
nonionic emulsifier
MCPA....--------------..............---.......... -- 2-methyl-4-chlorophenoxyacetic
acid
silvex..... .................... .---- ................-......2-(2,4,5-trichlorophenoxy) pro-
pionic acid
surfactant.....-.......... ---... .....------- ...............a material which facilitates and
accentuates the emulsifying,
dispersing, spreading, wetting
and other surface-modifying
properties of herbicide formu-
lations
2,4-D...--......------..------ .--.....-- ......-...2,4-dichlorophenoxyacetic acid
2,4,5-T--...........---.. ---.....--........---.....2,4,5-trichlorophenoxyacetic acid
Formulations of 2,4-D, 2,4,5-T, MCPA and silvex
alkali salts-...................--...---........-- ....sodium or potassium salts of
the acids
amine salts.................... ----------.............. alkylamine (e.g. di-or trimethyl-
amine, di- or triethylamine)
or alkanolamine (e.g. di- or
trimethanolamine, di- or tri-
ethanolamine), etc.
low-volatile esters.......--------------.......................................isooctyl, butoxyethanol, propyl-
eneglycol-butylether, etc.
volatile esters..............----------------................... methyl, ethyl, isopropyl, butyl,
etc.
granular --... ..................----------- salts or esters impregnated on
granules or pellets of clay
and other materials
water-in-oil "invert"..-----....... --......... --.............ester formulations which make
viscous emulsions with fuel
oil and water

ABBREVIATIONS USED

gpa gallons per acre
lb/A pounds of active ingredient or acid equivalent per surface acre
ppmv parts per million by volume. This final concentration of herbi-
cide formulation in the treated body of water is usually ex-
pressed in gallons of formulation per million gallons of water.
See calculations on page 15.
ppmw parts per million by weight. This final concentration of herbi-
cide in the treated body of water is usually expressed in pounds
of active ingredient or acid equivalent per million pounds of
water. See calculations on page 15.
v/v proportions by volume
psi pressure in pounds per square inch




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