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Title: Chemical weed control guide for Florida vegetable crops.
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Title: Chemical weed control guide for Florida vegetable crops.
Series Title: Chemical weed control guide for Florida vegetable crops.
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Publisher: Agricultural Extension Service
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Table of Contents
    Front Cover
        Front Cover
    Main
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
Full Text


Circular 196


April 1959


COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 80, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and
United States Iepartment of Agriculture. Cooperating
M. O. Watkins, Director










Chemical Weed Control Guide for

Florida Vegetable Crops

(Prepared in cooperation with workers of
the Florida Agricultural Experiment Stations)









*


AGRICULTURAL EXTENSION SERVICE
GAINESVILLE, FLORIDA






INTRODUCTION
Weed control by use of chemicals in vegetable
production is a relatively new agricultural prac-
tice. It offers great promise as a means of
reducing production costs in the growing of
vegetables by cutting down on hand labor and
number of cultivations. Generally, the chemicals
listed here have been tested less thoroughly than
is desired under the soil and climatic conditions
in Florida. For that reason, the grower is warned
to proceed with caution in introducing new chemi-
cal weed control practices on any of his vegetable
crops.
It is the purpose of this guide to assemble, in
brief form, the information that is available on
chemical weed control for commercial production
of vegetables in Florida. More detailed informa-
tion can be found in Special Report, ARS 22-46,
May 1958, of the Agricultural Research Service
of the USDA, "Suggested Guide for Chemical
Control of Weeds". Printed literature for each
chemical is generally available from the manu-
facturer. Contact your county agricultural agent
for more detailed information.

DEFINITION OF TERMS
1. Band application-an application of spray or
dust to a continuous restricted area, such as in
or along a crop row rather than over the entire
field area.
2. Directed application directionallyy) post-
emergence application of spray or dust aimed at
the soil or weeds at the base of the plants to
avoid crop contact and injury.
3. Herbicide-a chemical used for killing or in-
hibiting the growth of plants.
4. Pre-planting treatment- any treatment
made before the crop is planted.
5. Pre-emergence treatment any treatment
made after a crop is planted but before it emerges.
6. Post-emergence treatment any treatment
made after the crop plants emerge.






.7. Rate-usually refers to the amount of active
ingredient (such as 2,4-D acid equivalent) applied
to a unit area (such as one acre), regardless of
the concentration of the chemical in the commer-
cial product.
8. Selective herbicide -a compound that is
more toxic to one plant than to another.
9. Spray drift--the movement of airborne
spray particles from point of application to ad-
jacent areas.
10. Weed-a plant growing where it is not de-
sired.
11. Crop-a plant growing where it is desired.
12. Weed control-the process of inhibiting
weed growth and limiting weed infestations so
that crops can be grown profitably or other op-
erations can be conducted efficiently.

PRECAUTIONARY MEASURES
1. Read the label.
a. Many weed control chemicals are poison-
ous and are potentially dangerous to
man and animal. Follow safety precau-
tions given by the manufacturer.
b. Be sure the chemical is approved for use
on the crop you are treating. Follow
rate and time schedule on the label as
approved by the Food and Drug Ad-
ministration. Do not use chemicals that
do not have such approval.
2. Test new chemicals on a limited scale.
a. Before you attempt wide-scale use of
any new weed control chemical, test it
on a small scale for one or more seasons
until you are fully convinced of its value
and thoroughly familiar with its use.

GENERAL RULES
Rule 1- Know Your Weeds.
The various species of grasses and broadlea
weeds differ considerably in susceptibility to a





specific herbicide. Weeds are killed most readily
during the period of germination or during the
early stages of growth.
Rule 2 Know Your Chemicals.
Familiarize yourself with the following before
using a new herbicide:
(a) Potential hazards to handlers.
(b) Degree of susceptibility of each crop.
(c) Resistance of each weed.
(d) Restrictions on rates, timing and crops
for which approved.
(e) Any peculiarities specific to each herbi-
cide.

SOIL PREPARATION AND CARE
For pre-emergence weed control it is especially
important that you properly prepare the seed-
bed before you treat it with herbicides. It should
be free of crop residue, firm and smooth for best
results.
After the herbicide is applied, do not disturb
the treated soil unless otherwise specified for a
certain chemical. Exercise care in cultivation to
prevent untreated soil from being moved to a
treated area.

EQUIPMENT FOR SPRAYING
Application equipment must be suited for spray-
ing. Many types of sprayers can be used pro-
vided they have good agitation in the tank and
have pump capacity to deliver the necessary gal-
lonage per acre. When using wettable powders,
good agitation is especially important.
The boom and nozzles should be designed for
easy adjustment. Nozzle tips delivering a fan-
type spray pattern are generally used for applica-
tion of herbicides. Nozzle tips (and strainers)
should deliver the desired fan pattern and also
be suited to pump capacity and tractor speed.
Check with your equipment dealer to avoid guess-
work in selecting proper nozzles.





CALIBRATION OF SPRAYER
Calibration of the sprayer is an important fac-
tor in successful weed control. Unless the proper
amount of herbicide is applied in the proper way,
the operation may be a total failure.
Before each specific job, adjust the sprayer,
clean the screens and calibrate the sprayer in the
field on the tractor that will be used with it. For
overall soil coverage, adjust the boom so that
spray nozzle coverage overlaps one third at ground
level for pre-emergence spraying or at the tops
of growing weeds.
For band application, adjust height of boom
for the width of band desired. Usually, 8- to 12-
inch bands are used. Calibrate for the actual area
sprayed, not for the total acres in the field. For
example, only one fourth of the surface area is
sprayed if a 12-inch band application is used on a
48-inch row. Assuming a suggested rate of 6
pounds of a certain chemical per crop acre for
overall application, the above would require only
1.5 pounds of actual material.
One method of checking the rate of applica-
tion is as follows: Fill the tank with water, then
run the sprayer for 660 feet at the speed and
pressure to be used in actual operation, then re-'
fill tank with a measured amount of water to
determine gallons of solution used. Measure width
of actual area sprayed. For band application,
this is equal to the sum of the widths of all the
bands. Then calculate as follows:
Gallons used X 66
= gallons per acre
Width of sprayed area in ft.
24 ft.
= 33 gallons per acre*
12 gal. X 66
Any change in tractor speed, pressure setting,
nozzle size or band width changes the rate of
application and recalibration will be necessary.

*This amount of spray will cover one acre overall.
In the case of spraying 12" bands over rows 48" apart
(one fourth of the actual area), 33 gallons should cover
four acres. When preparing the spray, add the amount
of chemical recommended for one acre to the tank and
bring the volume up to 33 gallons with water.





CLEANING THE SPRAYER
It is almost impossible to clean a sprayer that
has been used for spraying herbicides. Hormone-
type weed killers cannot be removed completely
from wooden tanks or corroded metals parts.
Never use this equipment for other purposes, such
as application of insecticides, fungicides and liquid
fertilizers. Never allow the spray solution to
remain in the tank for long periods.
If it is absolutely necessary to use herbicide
equipment for other spraying purposes, try the
following cleaning procedures, although none is
completely safe and the sprayer can be used only
with considerable risk of damaging crops that are
sprayed with it.
1. Use soap or detergent for removing non-hor-
mone type weed killers.
2. Hormone-type weed killers, such as 2,4-D,
require chemical cleaning.
A. To remove water-soluble salt formula-
tions, use one of the following in 100
gallons of water:
(1) 1 gal. of household ammonia.
(2) 5 lbs. sodium carbonate (sal soda).
(3) 2 Ibs. sodium hydroxide (lye).
B. To remove oil-soluble emulsion formula-
tions, use either one of the following in
95 gallons of water:
(1) 2 lbs. sodium hydroxide (lye).
(2) 5 lbs. sodium carbonate (sal soda)
plus 5 gals. of kerosene and 1 lb. of
detergent.
Allow these solutions to stand in the sprayer
t least two hours, then drain out through boom
nd nozzles and rinse thoroughly with water. Re-
.ill the tank with water, then drain and flush be-
fore using again.
If sprayer has been used for copper spraying,
lo not use for DNBP until after it has been
leaned with 1 gallon of vinegar in 100 gallons of
water. Allow the cleaning solution to stand in
the tank, pump, hose and boom for two hours;
hen drain and rinse thoroughly with water.
7





COMMON AND TRADE NAMES OF SOME
HERBICIDES


Common Name
allyl alcohol
CDAA
CDEC
chloropicrin
CIPC


6. dalapon
7. DMTT

8. DNBP (alkanola-
mine salts)
9. EPTC
10. methyl bromide
11. NPA (sodium salt)
12. simazin
18. SMDC

14. mineral spirits
15. TCA (sodium salt)

16. 2,4-D (amine
salts)


Trade Name*
A-A Weed Seed Killer
Randox
Vegedex
Larvacide
Chloro-IPC (several
brands)
Dowpon
Mylone (several
brands)
Premerge, Sinox PE

Eptam
MC-2, Pestmaster
Alanap-3
Simazine
VPM Soil Fumigant,-
Vapam
several brands
Sodium TCA (several
brands)
2,4-D amine (several
brands)


HERBICIDES FOR VEGETABLE CROPS
The following weed control treatments have
performed well in Florida experiments or on com-
mercial farms and are suggested for grower trial.
Always check the container label for recent
changes regarding crops and rates approved by
the U.S. Department of Agriculture and the Food
and Drug Administration. Treatments listed in
bold type have been tested thoroughly; under
usual growing conditions they should give satis-
factory results. Those in light face type have
*The listing of specific trade names here does not
constitute endorsement of these products in preference
to others containing the same active chemical ingredi-
ents.






not been thoroughly tested and are, therefore,
only suggested for trial purposes.
The lower rates suggested are for the sandy
soils and the higher rates listed are for the
muck and peat soils.
Chemical rates of all herbicides, except for
soil fumigants, are given in terms of their active
ingredients as stated on the container labels. Ex-
cept for mineral spirits, all of these should be
mixed with water before being applied as sprays.
The rates of the soil fumigants allyl alcohol,
methyl bromide, DMTT, and SMDC are stated in
terms of their commercial formulations. These
materials are applied alone or as water drenches;
not as sprays.

BEANS
Pre-emergence:
CDAA-4 to 6 lbs./acre on sand or muck
CDEC-4 to 6 lbs./acre on sand or muck
DNBP-6 to 9 Ibs./acre on sand or muck
EPTC-2 to 4 lbs./acre on sand (stirred into
soil over seedbed)
Post-emergence (up to crook stage)
DNBP-3 Ibs./acre on muck

BEETS
Pre-emergence:
CDEC-4 to 6 lbs./acre on sand or muck
TCA-15 to 20 lbs./acre on muck
TCA-8 to 12 lbs./acre on sand
EPTC-2 to 4 lbs./acre on sand

CABBAGE, CAULIFLOWER, BROCCOLI,
COLLARDS AND KALE
Pre-emergence:
CDEC-4 to 6 lbs./acre on sand or muck
TCA-15 lbs./acre on muck (for grass)
CDAA-4 to 6 Ibs./acre on muck
Post-emergence:
CDEC--4 lbs./acre on muck (24 hours after
emergence)






CANTALOUPES
Pre-emergence:
NPA-3 to 4 lbs./acre on sand
Post-emergence:
NPA-3 to 4 lbs./acre on sand

CUCUMBERS
Pre-emergence:
NPA-3 lbs./acre on sand

CARROTS AND PARSLEY
Pre-emergence:
CIPC-10 to 12 lbs./acre on muck (during cool
weather)
Post-emergence:
CIPC-6 lbs./acre on weed-free muck soil
Mineral spirits-50 to 80 gals./acre at 3-leaf
stage
CIPC-4 lbs. in 30 gals. mineral spirits/acre on
muck
CELERY
Pre-seeding in seedbeds*-weeds, nematodes, and
diseases:
Cloropicrin-1.3 pints (2.3 Ibs.) per 100 sq. ft.
Methyl bromide-2 lbs. per 100 sq. ft.
DMTT-300 lbs./acre mixed in soil
SMDC-75 gals./acre drench
Pre-seeding in seedbeds-weeds only:
Allyl alcohol-40 gals./acre drench
Methyl bromide-1 to 2 lbs./100 sq. ft.
DMTT-80 to 160 lbs./acre as a drench on much
Post-transplanting:
CDEC-4 to 6 lbs./acre on sand or muck
CDAA-3 to 4 lbs./acre on sand
CIPC-10 lbs./acre on muck in cool weather
Mineral spirits-25 to 40 gals./acre on muck,
applied directionally
CDEC or CIPC-4 lbs. in 40 gals., mineral spir
its/acre on muck
*These treatments may be used also in the production
of transplants for certain other vegetable crops. Checl
the label before using for any crop.
10






ENDIVE (ESCAROLE AND CHICORY)
Pre-emergence:
CDEC-4 lbs./acre on sand or muck

LETTUCE
Pre-emergence:
CDEC-3 to 4 lbs./acre on muck or sand

ONION (seed and sets)
Pre-emergence:
CIPC-10 to 12 lbs./acre on muck
CIPC-4 to 6 lbs./ on sand
CDAA-4 to 6 lbs./acre on sand or muck
Post-emergence:
CIPC-10 to 12 lbs. (pelletized) /acre on muck
CIPC-4 to 6 lbs. (pelletized)/acre on sand

PEAS, ENGLISH
Pre-emergence:
CDAA-4 to 6 lbs./acre on sand or muck
DNBP-6 to 9 lbs./acre on sand or muck

POTATOES
Pre-emergence:
DNBP-3 lbs./acre on sand
Dalapon-5 to 10 lbs./acre on sand

SWEET CORN
Pre-emergence:
CDAA-4 to 6 lbs./acre on sand or muck
CDEC-4 to 6 lbs./acre on sand or muck
DNBP-6 to 12 lbs./acre on sand or muck
2,4-D-1.5 lbs./acre on muck
Simazin-2 to 3 lbs./acre on sand or muck
EPTC-2 to 4 lbs./acre on sand (stirred into
soil over seedbed)
Post-emergence:
DNBP-3 lbs./acre on muck at 2 to 3 leaf stage
2,4-D-% to lbs./acre at 1-inch stage on
sand or muck






/z to % lbs./acre at 12-inch to lay-by
on sand or muck
(don't use on early varieties)
Simazin-1 to 2 lbs./acre to lay-by on sand and
muck

WATERMELONS
Pre-emergence:
NPA-3 to 4 lbs./acre on sand
Post-emergence:
NPA-3 to 4 lbs./acre at lay-by on sand




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