Everglades Station Mimeo Report 62-4
CHEMICAL WEED CONTROL FOR VEGETABLE CROPS ON ORGANIC SOILS
OF THE EVERGLADES
J. R. Orsenigo 1/
This is a continuing revision of EES Mimeo Reports 57-6,
59-2, and 60-3. Recommendations and suggestions herein
are based on research conducted by the Everglades Experi-
ment Station and are supplemented by data developed else-
where. See also Florida Agricultural Extension Service
Circular 196. Growers are urged to observe the manufact-
urer's label and precautions for commercial usage of herbi-
cides in vegetable crops.
Although herbicides are valuable tools in commercial production of vegetable
crops they cannot be substituted for good horticultural practice. For best re-
sults in timely, effective and economical weed control in certain vegetables the
following must be observed:' USE THE RIGHT CHEMICAL FOR THE CROP AND WEEDS:
AT THE RIGHT TIME: IN THE RIGHT AMOUNT: IN THE RIGHT WAY AND IN THE RIGHT PACE.
These recommendations and suggestions are intended for grower guidance and
familiarization with herbicides and application methods. The potential of these
methods must be evaluated by the grower in his situation. Initial use of herbi-
cides should be restricted to a limited acreage and the precautions and indica-
tions of the manufacturer's label should be followed carefully.
Generally, band application of herbicides will be most economical since only
part of the total crop land will be sprayed. Whether the sprayer is planter-
mounted, tractor-mounted or trailed the following conditions should be observed:
spraying pressure = 20 to 40 psi; spray volume = 20 to 40 gpa; and flat-fan
herbicide nozzle tips. Good ground coverage is important and most pre-emergence
herbi ides are more effective when applied to a moist soil surface.
Granular formulations of some herbicides will be more convenient than liquid
sprays in some cases. Band application of granules with planter-mounted granular
distributors will make herbicide application economical, simple and timely where
All herbicide rates are expressed on a PER TREATED ACRE basis in terms of
usual commercial formulation. The customary active ingredient content of herbi-
cides mentioned in this report is given in the glossary along with herbicide
nomenclature and terminology. Appended are calibration procedures and illust-
rations of methods of application.
1/ Associate Horticulturist, University of Florida Everglades Experiment Station,
Belle Glade, Florida.
15 September 1961
GREEN BEANS PRE-EMERGENCE BANDED APPLICATION
RECOMMENDED: DINITRO 2 to 3 gal/A Pre-emergence
or 1 gal/A When beans are breaking through ground up to crook stage.
RANDOX 1 gal/A (or granular formulation at 20 lb/A)
VEGADEX 1 gal/A (or granular formulation at 20 lb/A)
SUGGESTED: EPIC 2 to 3 qts/A Incorporated into surface soil.
CABBAGE: DIRECT-SEEDED PRE-EMERGENCE BANDED APPLICATION
RECOMMENDED: RANDOX 4 to 6 qts/A (or granular formulation at 20 lb/A)
VEGADEX 4 to 6 qts/A (or granular formulation at 20 lb/A)
RANDOX + VEGADEX 4 to 6 qts/A Total tank mix of both components.
CELERY: O-ST-TRANSPLANTING BEFORE OR AFTER OVERHEAD IRRIGATION*
.COMMENDED: VEGADEX 4 to 6 qts/A Repeat application cleared up to one month after setting
RANDOX 4 qts/A Repeat application cleared up to 3 weeks after setting
RANDQX + VEGADEX 4 to 6 qts/A Total tank mix of both components; repeat applications
*Broadcast or banded directional sprays before or after overhead irrigation at setting but before
emergence of weed seedlings. Second application may be made to weed-free soil after side-dressing
is worked in. Equivalent active ingredient rates of granules may be used on a limited scale.
LEAFY CROPS: DIRECT-SEEDED PRE-EMERGENCE BANDED OR BROADCAST APPLICATION
(Chinese cabbage, endive, escarole, lettuce, romaine)
SUGGESTED: VEGADEX 2 to 4 qts/A LIMITED ACREAGE ONLY. Varietial tolerances not uniform.
Romaine usually injured.
CIPC 6 ot 12 qts/A LIMITED ACREAGE ONLY under moderate temperature condi-
tions. Usually weed control is inferior to Vegadex.
NOTE: "RECOMMENDED" and "SUGGESTED" are defined at the top of page 4.
ONIONS: DIRECT SEEDED OR SETS: PRE- AND POST- EMERGENCE BANDED APPLICATION
RECO1MENDED: RANDOX 6 qts/A* Use directed sprays post-emergence in weed-free onions.
CIPC 6 qts/A* Use directed sprays post-emergence in weed-free onions.
RANDOX + CIPC 6 + 6 qts/A* Tank mix.
Equivalent active ingredient rates of granular formulations may be band-applied in emerged onions. If
liquids are to be sprayed in emerged onions treatments should be withheld until plants are at least
6 inches tall.
SWEET CORN: IRE-EMERGENCE BANDED APPLICATION (use shallow planting furrow).
RECOMMENDED: ATRAZINE 5 Ib/A* Requires good soil moisture or rainfall.
DINITRO 3 to 4 gal/A Requires good soil moisture or light rainfall.
RANDOX 4 to 6 qts/A*
SIMAZINE 5 Ib/A* Requires good soil moisture or rainfall.
2,4-D amine 1 to 2 qts/A Short-period weed control.
VEGADEX 4 to 6 qts/A*
RANDOX + VEGADEX 4 to 6 qts/A* Total tank mix of both components.
*Equivalent active ingredient rates of granular formulations may be used.
SUGGESTED: EPTC 2 to 3 qts/A Incorporated into surface soil for grass and nutsedge
SWEET CORN: 'OST-EMERGENCE DRILL APPLICATION
EMMOCER NDED: DINITRO 2 to 4 qts/A
2,4-D amine 1/2 to 3/4 qt/A
ATRAZINE 3 to 4 Ib/A
overall oanaea at 2 to 4 leai stage; airectional to -- in.
Overall banded up to spike stage; directional to plants
12 inches and taller until lay-by. DO NOT APPLY TO
Directional sprays on small grass and broadleaf weeds
up until 3 weeks after planting.
NOTE: Usually, pre-emergence herbicides are effective only against germinating weed seed and very small weed
seedlings ordinarily, these chemicals will not control emerged weeds. Land should be freshly prepared,
seeded and promptly sprayed with herbicides. Operations are facilitated by planter-mounted equipment.
Randox + Vegadex mixtures are recommended for best control of annual grass and broadleaf weeds. Use
half-and-half for mixed weed populations; increase Randox rate for fields where grasses predominate
and increase Vegadex rate in mixture where broadleaf weeds are more serious. Do not exceed total tank
mix rates given.
NOTE: "RECOMMENDED" and "SUGGESTED" are defined at the top of page 4.
RECOMMENDED herbicidal treatments (chemical, rate and manner of application)
are those legally acceptable and considered generally reliable for commercial
production when used as specified. Growers without prior herbicide-use exper-
ience should confine initial applications to a limited acreage.
SUGGESTED herbicidal treatments represent promising materials which have not
been tested fully locally or those which do not have current label clearance
for the crops indicated. Growers may wish to utilize these on a very limited
WEED CONTROL ALONG MATERIAL DITCHES IN VEGETABLE FIELDS:
Pre-emergence to weeds:
RANDOX nt 3 to 4 qts/A PLUS VEGADEX at 3 to 4 qts/A: Apply in water
after planting but before weed seedlings emerge.
Post-emergence to small annual weeds:
RANDOX at 3 to 4 qts/A PLUS VEGADEX at 3 to 4 qts/A: Apply in 40
gpa of undiluted mineral spirits.
2-chloro-4-ethylamino-6-isopropylamino-s-triazine. As Geigy
"Atrazine 80W" 80% wettable powder or "Atrazine 8G" 8% granules.
isopropyl N-(3-chlorophenyl) carbamate. As 4 Ib/gal. emulsi-
fiable concentrate by Columbia-Southern, Diamond, Fasco, General,
Ortho and others and as 20% granules by Fasco, Woolfolk and others.
DNBP, alkanolamine salts of dintro-O-sec-butyl phenol. In 3 lb/
gal. emulsifiable concentrate as Dow "Premerge" or Standard Agri-
cultural Chemicals "Sinox PE".
ethyl N, I-di-n-propylthiolcarbamate. Stauffer's "Eptam 6E", a
6 lb/gal. emulsifiable concentrate.
CDAA, a-chloro-N,N-diallylacetamide. Monsanto's 4 lb/gal "Randox"
or 20% "Randox Granular".
2-chloro-4,6-bis(ethylamino)-s-triazine. Geigy as "Simazine 80W"
80% wettable powder or "Simazine 4G" 4% granules.
amine salts of 2,4-dichlorophenoxyacetic acid. As 4 Ib/gal.
formulations available from many suppliers.
CDEC, 2-chloroallyl diethyldithiocarbamate. Monsanto's 4 lb/gal
"Vegadex" or 20% "Vegadex Granular"
Band application using the herbicide in a narrow, continuous strip in, over
or along the crop row rather than over the entire field area.
Broadcast application using the herbicide over an entire field or area.
Contact herbicide an herbicide that kills principally by direct contact with
plant tissue rather than by translocation within the plant.
Directed application using an herbicide in a restricted location such as the
crop row or bed at the base of plants to avoid wetting plant
Overall application applying an herbicide from directly above a plant.
Post-emergence treatment applications made after crop plants emerge. Treat-
ments may also be specified as post-emergence to weed growth or
both crop and weeds.
Pre-emergence treatment applications made after a crop is planted but before
its emergence above ground. Treatments may be specified pre-
emergence to weeds. Usually, pre-emergence treatments in vege-
table crops are made before crop or weeds emergence. Contact
pre-emergence is a treatment made to kill weeds after they emerge
but before the crop comes up. Residual pre-emergence is a treat-
ment which kills weeds as their seed germinate or as they emerge,
either before or after crop come-up.
Pre-planting treatment application before a crop is planted.
Pre-transplanting treatment application before setting the transplant crop.
Post-transplanting treatment application after the crop has been field-set.
BASIC SPRAYING EQUIPMENT:
Herbicide tank with by-pass return for agitation.
Foot and/or line strainer.
Pump (Nylon roller or vane pump of about 6 gpm generally
satisfactory and economical).
Pressure regulator and gauge.
Quick-acting shut-off valve.
Hose and fittings (one-half inch satisfactory).
For most herbicide spraying in crops pressures in the range 20 to
40 psi are satisfactory and herbicides should be applied in about 20 to 40 gpa
of water. Any combination of tractor speed and nozzle tips to accomplish these
pressures and deliveries should be effective. Generally, spray drift is mini-
mized by low pressures and the larger nozzles which deliver coarse spray.
CALIBRATION: GENERAL PROCEDURE:
Initial calibration of a spray outfit may be accomplished easily
by the following procedure.
1. Adjust nozzles, spraying pressure and tractor speed as they
are to be operated in the field.
2. Fill herbicide tank completely with water.
3. With tractor operating as in number (1) above, spray water
over a measured course of several hundred yards in a fitted field.
4. Determine amount of water required to refill tank to replace
that sprayed over measured course.
5. Calculate area sprayed: Width of bands or boom spread-times
6. From 4 and 5 calculate quantity of water applied per acre.
7. Rate of application per acre can be decreased by: using
smaller nozzle tips, less pressure or faster tractor speed.
8. Rate of application per acre can be increased by: larger
nozzle tips, higher pressures or slower tractor speed.
9. When calibration is completed add desired quantity of herbi-
cide per acre to amount of water applied per acre by the spray unit.
10. Keep a running check on calibration by occasional testing and
by records of amount of herbicide used to treat each block of crops.
SPRAYER CALIBRATION TABLE FOR BAND-SPRAYING OF HERBICIDES:
This table will help determine sprayer output in gallons per acre
on a banded-spray basis.
TO USE: have sprayer equipped with proper nozzle tips and with
tips, tractor speed and spraying pressure adjusted as to be
operated in the field.
Then, drive unit in field and collect spray liquid discharged
by one or more nozzle tips over a distance of 300 feet. Several
tips collected separately and averaged are better than one.
Measure the liquid sprayed BY ONE TIP IN OUNCES. Locate this
figure in left column of table and read directly the gallons
per acre rate under the band-width column which applies to the
unit. Examples are below table.
Volume of spray
1 tip in 300 ft.
pt. or 8 oz.
1 pt. or 16 oz.
1 qt. or 32 oz.
GALLONS PER ACRE APPLIED AT BAND WIDTH OF:
9" 12" 15" 18"
NOTE: If two nozzle tips are used per row the value for one tip will have to
be doubled to give the correct gallons per acre total. If two tips are
used it would be desirable to calibrate unit to discharge in the area
above the dotted line in the table.
Example: 1 nozzle per row: a sprayer is set-up with one tip. spraying 12 inch
bands on the row. When run down the field at operating speed and
pressure a nozzle tip discharges 26 ounces of solution in 300 feet.
The gallons per acre rate is found in the 12" column opposite 26 ounces:
Example: 2 nozzles per row: a sprayer is set-up with 2 nozzle tips per row
and covers a 15" band. When run down the field at operating pressure
and speed ONE (1) nozzle tip discharges 16 ounces in 300 feet. As
indicated in the 15" band column opposite 16 ounces the nozzle is
spraying at 14.5 gallons per acre. However, since two tips are used
to spray this area the actual rate is TWICE 14.5 or 29 gallons per acre.
CALIBRATION OF GRANULAR BAND APPLICATORS:
1. Adjust delivery openings on applicator unit(s) at estimated or
approximate setting and fill hopper with granules to be applied.
2. Set tractor or unit speed as it will be operated in the field.
3. Operate the unit over a measured distance of several hundred
yards in a freshly prepared seedbed. Collect the granules discharged over
this course with pails or buckets under the delivery openings (remove
delivery tubes if necessary).
4. Accurately weigh the amount of chemical delivered by each outlet;
units should be set or adjusted to deliver identical amounts.
5. Calculate the area that would have been treated over the course:
multiply individual band width in feet by number of rows by distance covered
in feet. This value equals the area of the measured, treated course in
6. From #4 and #5 calculate the amount of granules applied per acre
Pounds per acre = 43560 x pounds granules applied over course(4)
area of measured course in square feet (#5)
This value is pounds per acre (ib/A) of granular formulation applied.
To determine amount of active ingredient applied multiply pounds per
acre by percent active ingredient and divide by 100 as follows:
Pounds per acre active = lb/A granules from above x 5% active
7. Rate of application is increased by wider delivery openings.
8. Rate of application is decreased by narrower delivery openings.
9. Complete calibration by repeatedly adjusting and testing unit
until desired quantity of granules is delivered. All individual delivery
spouts should have the same output.
10. Keep a running check on calibration by occasional testing and by
records of amount of herbicide used to treat each block of crops.
Example: A granular chemical applicator treats 1 ft. bands on 5 crop
rows (5 rows x 1 ft. = 5 ft. treated). When driven over a distance of
870 ft. each of the five openings delivered 4/10 pound of herbicide
(5 rows x 4/10 pound = 2 pounds) at the setting used.
Pounds per acre 4=3560 sq. ft. x 2 pounds granules 20 b/A granules
Punds per acre 5 ft. x 870 ft.
If the active ingredient concentration of the granules was 20%, the
rate of active material applied per acre was:
Pounds per acre = 20 Ib/A granules x 20% = 4 Ib/A active
active ingredient 100
HERBICIDE APPLICATION METHODS: BROADCAST SPRAYING:
.- -. ... oo
Pre-emergence overall Post emergence overall
USE "FAN-TYPE" TIPS WITH 1/4 TO 1/3
NOZZLE PATTERN OVERLAP TO OBTAIN
UNIFORM COVERAGE. "FAN-TYPE" TIPS ,-
HAVE AN ELLIPTICAL SPRAY DENSITY
PATTERN AND MUST OVERLAP FOR
UNIFORMITY. AN EXAMPLE OF THIS
TYPE TIP IS "TEE-JET" SERIES *
*(series 6500, 7300 and similar tips
of other manufacturers are also
HERBICIDE APPLICATION METHODS: BAND SPRAYING'
.. ..boom or
USE "PRE-EMERGENCE FAN-TYPE" TIPS SUCH AS
"TEE-JET" 8000 E SERIES. THE SPRAY
PATTERN OF THIS "FAN-TYPE" TTP HAS
UNIFORM SPRAY DENSITY ACROSS FAN
PATTERN. SATISFACTORY BAND WIDTH
8 to 12 INCHES.
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