For Commercial Use Only
* Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
John T. Woeste, Dean for Extension
SWEET CORN PRODUCTION GUIDE
(Revision of Circular 99C)
The purpose of this guide is to present general
recommendations for the production of sweet
corn in Florida. For details on local application
of these practices, see your county Extension
agent. Additional information on sweet corn pro-
duction can be found in the following publica-
tions: University of Florida Extension Circulars
193, 196, 225 and Experiment Station Bulletin
596 and Circular S-234. Since Extension circulars
are revised from time to time, be sure to obtain
the latest editions.
Many sweet corn hybrids are released each year.
Trials to screen sweet corn varieties for perform-
ance under Florida conditions are conducted each
year by research workers of the Florida Agricul-
tural Experiment Stations. Varieties listed here
are those that performed well in one or more lo-
cations in Florida. Listing of only these varieties
is not meant to imply that other varieties may
not be suitable to Florida, also.
Iobelle (Fla. 104)-Medium size plant of mid-
season maturity. Ear attractive, pale yellow. It is
planted for all season production. Susceptible to
Florigold 106, 106A and 107-Medium size
plants of midseason maturity. Ears yellow and
of very good appearance, but with poor husk
cover under some conditions. Tolerant to leaf
Gold Cup-Medium size plant of midseason
maturity. Yellow. Fair quality. Susceptible to
leaf blights. More suitable for production in Cen-
Silver Queen-Tall plant of midseason maturity.
White, excellent quality. Susceptible to leaf
Wintergreen-Medium plant of midseason ma-
turity. Ear yellow and of fair appearance. Tolerant
to leaf blights.
Carmelcross and Northern Belle-Plant small,
early maturity. Ear yellow and only of fair ap-
pearance. Susceptible to leaf blights.
Other Varieties-Bonanza, Florida Sweet (A
new Florida release in limited supply).
Acreage and Harvest Periods*
Areas in Florida
North & West Florida
North Central Florida
State Total 49,900
*From Florida Agricultural Statistics, Vegetable Sum-
Area Dates Days to Maturity
North Florida March-April 75 to 100
Central Florida August-September "
South Florida August-March "
Spacing and Seeding
28" to 42"
8" to 15"
1" to 2"
5 to 12 Ibs
'Rates can be reduced by a 50 percent or more with pre-
Yields, Costs and Returns*
Range Per Acre (1974-75 Season)
Central Florida (Muck) Lower East Coast (Sand) Everglades (Muck)
Range: From To Range: From To Range: From To
Yield (Crates) 228 361 141 238 168 308
Total growing cost $ 253.31 $ 517.05 $ 316.79 $ 390.53 $147.41 $ 430.79
Total harvesting &
marketing cost 334.01 660.12 288.33 436.20 332.15 636.81
Total crop cost 728.69 1,103.35 605.33 803.33 590.05 1,062.61
Crop sales 974.11 1,535.50 577.78 825.30 651.55 1,036.34
Net return $ 229.50 $ 494.02 ($-110.05) $ 119.54 ($ -44.48) $ 397.65
*From Economic Report 49, March, 1976, Food & Resource Economics Department, University of Florida. (NOTE: Ranges from
low to high are for each item and are not additive in columns.)
For seed that is purchased untreated, treat with
a Thiram fungicide. Thiram is available under
several trade names and should be used as recom-
mended on the label.
Neither yield nor earliness is improved by re-
moving suckers which are normally produced at
the base of the plant.
Timing.-The basic application of fertilizer may
be applied before planting, during planting, short-
ly after planting, or in split applications combining
any two or all three of these. Supplemental fer-
tilizer may be applied whenever needed during the
growing season and especially after heavy, leach-
Soil pH.-Optimum range for sweet corn pro-
duction is between 6.0 and 6.5. Where magnesium
levels are low, use dolomitic limestone.
Micronutrients.-A general guide for adequate
micronutrients in the absence of past experience
or soil test is the addition of 0.3 percent MnO, 0.2
percent CuO, 0.3 percent Fe20s, 0.2 precent ZnO,
and 0.2 percent B20a with the fertilizer. The micro-
nutrients can be obtained from chelates, mixtures
of oxides and sulfates or fritted materials. Grow-
ers should consider the nutrients present in the
fungicides used in the overall management of a
Higher rates are necessary to overcome the ten-
dency of micronutrients to be completed or tied-
up by the organic matter in muck and peat soils
and from high pH on marl soils.
The amount of fertilizer suggested here is suf-
ficient to grow these crops under normal condi-
tions. Most crops will respond to supplemental
applications of nitrate-nitrogen during periods
of cool weather or following heavy rainfall.
Fertilizers-Rates and Use
S Supplemental applications
application Actual lbs
actual Ibs/ each
acre application Number of
Soil N-P205-K20 N-P205-K20 applications
Mineral soils' 90-120-120 30-0-15 1 to 4
Mineral soils2 72- 96- 96 30-0-15 1 to 2
Muck & Peat 0-160-180 see3 see3
Marl 54- 72- 72 30-0-15 1 to 2
Rockland 45- 60- 60 30-0-30 1 to 2
'Includes all mineral soils (except marl and rockland)
having a dependable supply of moisture.
2Includes all mineral soils (except marl and rockland)
not having a dependable supply of moisture.
3The amount of fertilizer suggested here is the amount
needed for organic soils low in P205 and K20. When
soil tests show a medium level of P205 in an organic soil,
reduce the amount of P205 suggested here by one-third;
when soil P205 levels are high, reduce by two-thirds. Fol-
low the same suggestions for medium and high levels
On new peat soils, make a broadcast application
of 15 pounds of CuO, 10 pounds of MnO, and 4
pounds of B203 per acre before any crop is
Sweet corn can be severely injured by several
kinds of nematodes. The most serious pests in
Florida sandy soils include sting, stubby-root, awl,
root-knot, lesion and lance nematodes. Those most
severe in organic soils include stubby-root, spiral,
stunt and root-knot nematodes. Soils known to be
heavily infested with these nematodes should be
avoided if possible. Fallow cultivation, crop ro-
tations and flooding may all be used to reduce
populations of pest nematodes.
If sweet corn must be planted in infested soil,
the nematicides listed in the following table may
be used to reduce losses to nematodes. The fumi-
gants must all be used before planting. See labels
for specific instructions for application and wait-
ing periods. The contact nematicides may be ap-
plied in a band over the row at planting time.
The overall rate for the soil fumigants is based
on a 12-inch chisel spacing. The "Gal/acre"
figures for row applications assume use of a
single chisel per row with 36 inches between rows.
Wider spacing between rows will result in use of
less total fumigant per acre and closer spacing
will require more. If two or more chisels are used
per row and they are 12 inches apart, the rate per
chisel should be the same as for overall treatment.
If chisels are closer than 12 inches, reduce the
rate per chisel proportionately. The rate of fumi-
gant applied within the area of the row that is
actually treated should not exceed the maximum
overall rate except as noted for single-chisel row
treatment with D-D and Telone II.
The rates of fumigants listed are for mineral
soils; they should be increased for organic soils
(peat or muck) as noted in label directions.
Rates of non-fumigant materials are given in
pounds of formulation. Mocap 10G should not be
used as a seed furrow treatment. Use the higher
rate of Mocap 10G except where sting nematode
is the only major nematode pest.
Nematicides Overall Row
Fl oz/chisel Fl oz/chisel
per 1000 per 1000
Fumigants Gal/acre linear ft Gal/acre linear ft
D-D 20-25 59-73 9.0-11.0 79-97
Telone II 12-15 35-44 5.3- 6.7 47-58
Dowfume W-86 4.5-6.0 13-18 1.5- 2.0 13-18
Contact Lbs/1000 band/1000
nematicides Lbs/acre sq ft Lbs/acre linear ft
Dasanit 15G 13.5 14.5 oz
Mocap 10G 60 1.5 15-20 1.2-1.5 lbs
Chemical Weed Control
Herbicides-Rates and Uses
Rate: (lbs active
Time of ingredients/acre)2 3 4
Herbicides to crop' Sandy soil Muck soil Remarks
alachlor Preemergence 1% to 2 3
atrazine Preemergence 2 (3) Adequate surface soil moisture is essential
(Several brands) for good results. Has label restriction
on when and what crops can follow
in treated area.
alachlor+ Preemergence 1%+1 2+1% See remarks under atrazine.
CDAA Preemergence (5) 5 More effective on grasses than
(Randox) broadleaf weeds.
CDEC Preemergence 6 4 to 6 More effective on broadleaf
(Vegadex) than grass weeds.
CDAA+CDEC Preemergence (3+3) 3+3
simazine Preemergence (2) See remarks under atrazine.
atrazine Postemergence 2 3 Will control weed seedlings up to 1%
inches tall. See remarks under atrazine.
atrazine & oil Postemergence (1+1 gal) (2+1 gal) Use a non-phytotoxic crop oil plus
emulsifier formulated for use with
atrazine. See remarks under atrazine.
Pre and postemergence.
2,4-D Postemergence (aY to %) (1% to %) Apply directionally to base of crop plants
for small broadleaf weeds. Use amine
formulation. Do not apply air. Some
varieties susceptible to injury. Do not
use after start of ear formation.
'All treatments are "preemergence" to weeds unless stated otherwise under remarks.
2Rates given are on a broadcast basis. If banded applications are used, the amounts will be proportionately less.
3Rates given in parenthesis are suggested for trial purposes only.
4Use minimum of 20 gallons of water per acre for ground application or 5 gallons per acre for aerial application.
Application of Insecticides and Fungicides
The amount per acre of insecticides and fungi-
cides recommended under "Insect Control" and
"Disease Control" is for full-grown crops and
should be reduced proportionately for smaller
plants. "Minimum Days to Harvest" means the
minimum number of days that must elapse~be-
tween last foliar application and harvest. If the
dosages recommended are exceeded, the minimum
days listed may not be applicable and a longer
interval should be allowed.
The amount of spray or dust required for ade-
quate coverage varies according to size of the
plants. Generally, 50 to 150 gallons of spray or
20 to 35 pounds of dust are sufficient for good
coverage. Pressure in spraying should not exceed
PRECAUTIONS: All pesticides should be used
with extreme caution. Read the label and follow
recommendations on crop use, dosage and time
lapse required between last application and har-
vest. Study suggestions for safety and follow
Insecticides-Rates and Use
feeding in bud2
Mevinphos (Phosdrin) 2E
Gardona 75% WP
Methomyl (Lannate, Nudrin) 90% SP
Methomyl (Lannate, Nudrin) 1.8 EC
Parathion-methyl parathion 6-3E
Silk-Fly3 Parathion 4E 5
Earworms4 Gardona 75% WP 2/3-1 lb* NTL
Methomyl (Lannate, Nudrin) 90% SP A lb* NTL
Methomyl (Lannate, Nudrin) 1.8 EC 1-2 pts NTL
Parathion-methyl parathion 6-3E pt* 5
Carbaryl (Sevin) 80% WP 2' lbs* NTL
Corn Stem Weevil5 Gardona 75% WP 1% lbs NTL
Methomyl (Lannate, Nudrin) 90% SP '% lb NTL
Cutworms See footnote #6 below.
Wireworms See footnote #7 below.
Lesser Cornstalk See footnote #8 below.
% pt plus
*These amounts should be mixed in 50 gallons of water and applied to one acre.
**NTL-No time limit.
***Other formulations may be registered and available.
1Aphid and Spider Mites-Infestation of these pests may become heavy enough to require control measures in some areas of the
2Fall Armyworms and Corn Earworms Feeding in the Corn Bud-Spray weekly or more often, depending on severity of infestation.
For cleanup of budworms and fall armyworms, a routine application of insecticides should be made between the appearance of the
tassel and appearance of silks. Direct the spray from above and from each side of the plant to the upper leaves to thoroughly wet
and run down into the bud-whorl. Spray pressure should not be excessively high; 150 pounds per square inch or lower is prefer-
able. There should not be any fog coming from the nozzles.
3Silk-Fly-Check for adult silk-flies just before and during silking.
_ 4Earworms-For control, timing and good coverage are essential. Treatments must be started when the silks first appear and con-
S tinued until all the silks are dry or brown. Additional applications may be needed where renewed silk growth occurs after normal
browning. Applications of one of the recommended insecticides will give control when applied at 48-hour intervals to sweet corn
silking during October through March. During the rest of the year, apply one of the recommended insecticides every 24 hours.
The amounts of insecticides recommended in the preceding table should be mixed with 50 gallons of water and applied to one
acre. The dust must be applied at 25 to 30 pounds per acre. Dusts or sprays should be directed to thoroughly cover the silks.
5Corn Stem Weevil-Treatments must be started when the first seedlings emerge from the soil and continued every four days or
two times a week for six applications or until corn stem is /2-inch or more in diameter. Sprays must be directed to the lower
stem and the adjoining soil. Use overhead nozzles to apply 50 gallons per acre until the foliage begins to form a canopy that
prevents the spray from reaching the ground and lower stem. Then add a nozzle to each side of the row and increase the rate to
100 gallons per acre. Cultivation should be as infrequent as possible during this spray schedule and should precede a spray appli-
cation. Preemergence chemical weed control (See Extension Circular 196) and delay of the first cultivation until after the final
corn stem weevil spray has resulted in better corn stem weevil control. The corn stem weevil has been recognized as a pest only
in the Everglades.
"Cutworms-Apply toxaphene, or chlordane at 2 pounds active ingredient (5 pounds of 40 percent WP or 20 pounds of 10 percent
dust or granules) per acre to the soil surface before planting if cutworms are know to be present. Do not disturb soil for three
to five days. A 21 percent toxaphene or 2 percent chlordane or 5 percent Dylox bait can be used as above at 20 to 40 pounds
per acre. If cutworm damage to young plants is noted, baits should be used at once. Regular applications of insecticides recom-
mended for control of foliage insects will prevent the establishment of cutworms. A home-made bait can be prepared by thoroughly
mixing 5 pounds of 40 percent chlordane WP or 6 pounds of 40 percent toxaphene WP with 100 pounds of wheat bran. Moisten
bait slightly with water and apply in the late afternoon. Use freshly mixed baits.
(NOTE: Chlordane may possibly become unavailable or be taken off the market within the year. However, it is presently avail-
able and legal to use. If such action takes place, use one of the alternative insecticides recommended for the pest in question.)
TWireworms--Apply parathion or diazinon at 2 pounds active ingredient per acre on mineral soils; on organic soils apply para-
thion at 5 pounds or diazinon at 4 pounds active ingredient per acre. Distribute evenly over the soil surface 2 to 3 weeks before
planting and immediately mix into the upper 6 inches of soil. Dyfonate at 4 lbs. ai/acre has controlled wireworms on organic
8Lesser Cornstalk Borer-In the Everglades area apply parathion, using a wetting agent or detergent in the spray water to help
wet the soil and the webbing. Make first application broadcast (covering rows and middles) just before crop emerges, using 1
pint of parathion 4E per acre. Make second application as soon as crop emerges and before cultivation, using 1 pint of parathion
4E per acre. Higher gallonage (up to 300 per acre) of more dilute coarse sprays at about 100 pounds pressure may be more ef-
fective. The lesser cornstalk borer is an erratic pest with outbreaks during dry periods; it is doubtful that routine control meas-
ures would be profitable.
PRECAUTIONS: Read pesticide labels thoroughly before opening container, and observe all safety precautions. Dispose of empty
containers promptly and safely. Information is given on recommended pesticides and minimum days between last application
and harvest. There will be changes and cancellations; therefore, the grower is urged to keep abreast of developments through
county agents, experiment stations and industry representatives.
Northern Leaf Blight (Helminthosporium turci-
cum)-When weather is warm and humid, fre-
quent fungicide sprays are necessary for disease
control. Suggested fungicides are:
Spray to harvest
Maneb 80% 11/ lbs, or NTL*
Polyram 80% 11/2-2 Ibs, or 1* **
Zineb 70% 2 lbs, or NTL***
Dithane M-45 1% lbs, or 7
Manzate 200 1 z lbs, or 7
Bravo 75W 11/2-2 lbs, or 14****
Bravo 6F ll/-2pts/A 14****
Difolatan 4F % to 2 pts (by air) 5****
*Do not feed treated foliage to livestock.
**Use restricted to Florida. Do not use on sweet corn
***Do not feed forage or husks to dairy animals or ani-
mals being finished for slaughter.
****Do not apply to sweet corn for processing. Do not
graze treated fields. Do not ensile or use treated corn
for feed or forage.
Any of the materials properly applied once or
twice weekly, depending on weather and disease
conditions and locations, will give economic con-
trol. Forecasting systems which reduce the num-
ber of spray applications directed at Helmintho-
sporium turcicum are available for the Belle Glade
area. For crops in the "whorl stage" of growth,
the sprayer should have two nozzles over the row
in addition to the side nozzles required for com-
plete coverage of unfurled leaves. Maneb, Man-
zate 200, Dithane M-45, and zineb should also
give satisfactory control of corn rust. Where it
is practical, use Helminthosporium resistant
Southern Leaf Blight (Helminthosporium may-
dis)-See control given for Northern leaf blight.
Rust (Puccinia sorghi)-Use zineb as given for
Northern leaf blight.
Bacterial diseases (bacterial leaf blight, stalk
rot and basal ear rot) (Pseudomonas alboprecipi-
tans and P. andropogonis)-No practical control
measures are known. It has been observed that
these diseases often spread from ditch banks to-
ward the center of fields. Thus, control of
grasses, which act as host plants, may aid in re-
ducingThse verityl-fthis problem.
Harvesting and Handling
Quality of sweet corn starts to deteriorate
immediately after harvest. Time lapse between
harvest and precooling (removal of field heat)
should be kept to a minimum to conserve quality.
Sweet corn should be harvested at the proper
stage of maturity, rapidly cooled to 320 to 40F
and maintained in that temperature range until
consumed. Since these temperatures are seldom
attained with existing precooling facilities, top-
icing during shipping is highly desirable.
The use of trade names in this publication is solely
for the purpose of providing specific information. It is not
a guarantee or warranty of the products named and does
not signify that they are recommended to the exclusion
of others of similar composition.
Prepared by: James Montelaro
Acknowledgements: The author wishes to express his
sincere thanks to the many faculty members of the In-
stitute of Food & Agricultural Sciences who made many
helpful suggestions in the preparation of this circular.
Special contributions were made by:
R. K. Showalter-Harvesting and Handling
J. E. Brogdon and F. A. Johnson-Insect Control
R. S. Mullin and T. A. Kucharek-Disease Control
R. A. Dunn-Nematode Control
S. R. Kostewicz-Weed Control