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 Front Cover
 Field corn production
 Back Cover






Group Title: Circular (Florida Cooperative Extension Service) ;, 144E
Title: Field corn production guide
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00055217/00001
 Material Information
Title: Field corn production guide
Series Title: Circular (Florida Cooperative Extension Service)
Physical Description: 18 p. : ; 23 x 10 cm.
Language: English
Creator: Johnson, J. T
University of Florida -- Institute of Food and Agricultural Sciences
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla.
Publication Date: [1974?]
 Subjects
Subject: Corn -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
General Note: Cover title.
General Note: Prepared by J.T. Johnson, D.W. Jones, D.W. Dickson, W.L. Curey, and T.C. Skinner.
General Note: "6-10M-74"--P. 18.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00055217
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 51245779

Table of Contents
    Front Cover
        Page 1
        Page 2
    Field corn production
        Page 3
        Varieties
            Page 3
        Planting dates
            Page 4
        Liming and fertilization
            Page 5
        Forms of nitrogen
            Page 6
        Plant population
            Page 7
        Nematode control
            Page 8
        Insect control
            Page 9
        Weed control
            Page 9
        Harvesting
            Page 10
        Drying and storing
            Page 10
            Page 11
        Control of stored grain pests
            Page 12
            Page 13
        Table 6: Recommended insecticides and rates of application
            Page 14
            Page 15
        Table 7: Herbicides recommended for use on field corn
            Page 16
            Page 17
    Back Cover
        Page 18
Full Text






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FIELD CORN PRODUCTION


Field corn is an important agronomic crop in
Florida with more than 400,000 acres planted in
1973. Approximately 85 percent of the acreage
was harvested for grain with a value of more than
30 million dollars. The remaining acreage was
cut for silage or hogged-off.
Corn production is concentrated on the mineral
soils in the north central and northwest Florida
counties. A small acreage, however, is produced
on the organic soils in central Florida. The min-
eral soils used for corn production vary consider-
ably in texture, organic matter and drainage, and
consequently in their ability to retain and supply
moisture to the growing crop. In many cases low
soil fertility is a limiting factor in corn produc-
tion.
Research results show that corn yields in Flor-
ida can be increased by planting good seed of
adapted hybrids, application of needed quantities
of plant nutrients, spacing plants according to soil
type and improving weed, insect and nematode
control practices.

Varieties
The hybrids recommended have been evaluated
in Florida Agricultural Experiment Station vari-
ety trials for at least two years. Average grain
yields for two years (1972-73) and ratings on
standability, ear quality, husk cover, ear height
and the number of ears per plant are shown in
Table 1. The hybrids listed are recommended for
use throughout Florida.
The yellow hybrids are divided into three matur-
ity groups-full season, mid-season and early
season. The majority of the Florida corn acreage
is planted to full season hybrids. These hybrids
silk from 5 to 10 days later than the early season
hybrids and require more time to fill the ear be-
fore drying down. The full season hybrids gener-
ally have better husk cover and higher ear and
grain quality than the earlier hybrids. Full sea-
son hybrids should be planted if the corn is to be
combined late.
The early season hybrids are suggested for the






FIELD CORN PRODUCTION


Field corn is an important agronomic crop in
Florida with more than 400,000 acres planted in
1973. Approximately 85 percent of the acreage
was harvested for grain with a value of more than
30 million dollars. The remaining acreage was
cut for silage or hogged-off.
Corn production is concentrated on the mineral
soils in the north central and northwest Florida
counties. A small acreage, however, is produced
on the organic soils in central Florida. The min-
eral soils used for corn production vary consider-
ably in texture, organic matter and drainage, and
consequently in their ability to retain and supply
moisture to the growing crop. In many cases low
soil fertility is a limiting factor in corn produc-
tion.
Research results show that corn yields in Flor-
ida can be increased by planting good seed of
adapted hybrids, application of needed quantities
of plant nutrients, spacing plants according to soil
type and improving weed, insect and nematode
control practices.

Varieties
The hybrids recommended have been evaluated
in Florida Agricultural Experiment Station vari-
ety trials for at least two years. Average grain
yields for two years (1972-73) and ratings on
standability, ear quality, husk cover, ear height
and the number of ears per plant are shown in
Table 1. The hybrids listed are recommended for
use throughout Florida.
The yellow hybrids are divided into three matur-
ity groups-full season, mid-season and early
season. The majority of the Florida corn acreage
is planted to full season hybrids. These hybrids
silk from 5 to 10 days later than the early season
hybrids and require more time to fill the ear be-
fore drying down. The full season hybrids gener-
ally have better husk cover and higher ear and
grain quality than the earlier hybrids. Full sea-
son hybrids should be planted if the corn is to be
combined late.
The early season hybrids are suggested for the







early cash grain market and for hogging-off. The
early hybrids have relatively poor husk cover and
should be combined early to preserve grain quality.
Any of these hybrids are suitable for silage
production. The full season hybrids generally
produce larger plants and a higher tonnage of
silage. The early season hybrids produce as much
grain on smaller plants, thus the percentage of
grain in the silage is higher.

TABLE 1. Characteristics of hybrid corn varieties
recommended for Florida





Brand Z W U" 1 -
Full Season Yellow Hybrids
McNair 508 101 88 good good 3.8 1.41
PAG 751 101 68 good good 4.1 1.36
Funks G-5945 100 78 good good 3.9 1.16
Funks G-4949 99 89 good fair 3.9 1.08
Dekalb 1214 99 81 good good 4.0 1.40
Coker 54 95 82 exc good 3.6 1.31
Coker 71 89 79 good good 4.2 1.26
Greenwood 471 89 72 good good 4.4 1.16
Pioneer 3030 87 83 good exc 3.5 1.09
Mid-Season Yellow Hybrids
McCurdy 67-14 98 82 good fair 3.1 1.00
McNair S-338 96 85 fair fair 3.1 1.01
Funks G-4864 95 87 good good 3.4 1.00
Greenwood 95 93 83 good good 3.3 1.16
Greenwood 45 92 83 good fair. 3.1 1.17
Pioneer 3009 92 79 good exc 3.6 1.00
Greenwood 228 91 83 good good 3.4 1.20
Early Season Yellow Hybrids
McNair X-300 94 83 fair good 2.9 1.00
Funks G-4761 92 85 fair fair 2.8 1.05
Dekalb XL-389 91 89 poor poor 3.4 1.01
Pioneer 3369A 90 91 fair fair 2.7 1.02
McNair X-210 90 88 fair good 2.8 ,97
Funks G-5757 89 83 fair poor 2.9 1.04
Mid-Season White Hybrids
Pioneer 511-A 100 69 good good 3.4 1.28
Funks G-795W-1 97 62 good good 3.5 1.22
Coker 814 94 77 good good 4.2 1.31
PAG 653-W 93 72 good good 3.7 1.34

Planting Dates
Plant during the planting season recommended
for the area at times when temperature and soil






moisture conditions are favorable for germination
and growth. Recommended planting dates by
areas are:
Southern Florida Feb. 15- Mar. 15
Central Florida Mar. 1 Mar. 31
Northeastern Mar. 15- Apr. 15
Northwestern Mar. 15- Apr. 15

Liming and Fertilization
Good liming and fertilization programs are es-
sential for good corn yields in Florida. The first
step in developing sound liming and fertilization
programs is to determine the nutrient status of
the soil by means of a soil test. Soil test results
provide the information needed to make accurate
liming and fertilization suggestions.

LIMING-Adding lime to acid soils decreases
soil acidity (reduces pH) and affects the chemical
properties of the soil, making some nutrients more
available while toxicities caused by excessive con-
centrations of other nutrients is reduced. De-
sirable microorganisms grow better in well limed
soil. Calcic limestone supplies the plant nutrient
calcium while dolomitic limestone supplies both
calcium and magnesium.
Corn grows best when the soil pH is 5.5 to 6.5
with minimum CaO and MgO values of 600 and
100 lb/A, respectively. Usually one ton of lime
every third year is sufficient with normal cropping.
When high rates of nitrogen fertilizers are used,
lime will be needed more frequently.
FERTILIZATION-A good corn fertilization
program involves applying the proper kinds and
rates of fertilizer materials at the correct time.
Recommended rates of fertilization are shown in
Table 2.

PREPLANT-All the phosphorus (PO2s) and
potassium (K20) and about 25 percent of the
nitrogen (N) may be broadcast and disk-incorpo-
rated or plowed down not more than two to three
weeks prior to planting. It is important not to
apply mixed fertilizers too long before planting
since some leaching loss of nitrogen and potassium
can occur with heavy rainfall.
5







AT PLANTING-It is not necessary to band
any mixed fertilizer by the row at planting if ade-
quate quantities were broadcast before planting.
If some fertilizer is banded, place the bands three
inches to the side and three inches below the seed.
Not more than 50 percent of the mixed fertilizer
should be banded to avoid the possibility of "fer-
tilizer burn."
SIDEDRESSING-Nitrogen, 96 to 144 pounds
per acre, should be applied as a sidedress applica-
tion when the plants are about 2 feet high unless
anhydrous ammonia is used as the nitrogen source.
Anhydrous ammonia can be plowed down before
planting, applied just after planting or at the first
cultivation. The rate of sidedress nitrogen will
vary with plant populations.

TABLE 2. Recommendations for Fertilization of Field
Corn Without Aid of Soil Test Results
Recommended Rates
of Application
Texture of Plants Per Pounds Per Acre of:
Surface Soil Acre N P,0O K,0
Sand and1 10,000 128 64 96
light loamy 12,500 160 80 120
sand 15,000 192 96 144
Heavy loamy sand' 10,000 128 96 96
and sandy loam 12,500 160 120 120
15,000 192 144 144
Organic2 20,000 0 96 128
soils
1 If zinc deficiency is likely to occur, the mixed fertilizer
should contain enough zinc sulfate to supply four pounds
of ZnO per acre. Minor element deficiencies can be
prevented by applying a complete fritted trace element
mixture every third year.
2 Copper oxide should be applied annually at the rate of
five pounds per acre.

Forms of Nitrogen
Either liquid or dry nitrogen formulations are
suitable for sidedressing corn. Most liquid nitro-
gen solutions are composed of either ammonium
nitrate or ammonium nitrate + urea in water solu-
tion. Care should be exercised during application
since both dry and liquid formulations of nitrogen
will cause leaf damage if applied to the foliage.
Nitrogen formulations that contain urea may
not be as effective as other nitrogen sources when







applied to the soil surface under some conditions.
Unless urea is incorporated into the soil by culti-
vation or leached into the root zone by rainfall
soon after application, up to 1/3 of the nitrogen
in urea can be lost as ammonia gas by action of
the urease enzyme. This problem does not occur
with other nitrogen sources.

Plant Population
Plant populations should be based on the ability
of the soil to supply and retain moisture during
the growing season and on the maturity of the
corn hybrid planted. The early and mid-season
hybrids produce smaller plants than the full sea-
son hybrids and should be planted at higher pop-
ulations as indicated in Table 3.
Irrigation can be an important corn production
tool. When moisture can be supplied as needed
throughout the growing season, 18,000 to 22,000
plants per acre is suggested.

TABLE 3. Recommended Plant Populations for Soils
with Different Moisture Conditions
Soil Moisture Suggested Plant Populations
Holding Capacity Plants/Acre
Full Season Early and Mid-
Hybrids Season Hybrids
Low 10,000 12,500
Medium 12,500 15,500
High 15,000 18,500
Very High 20,000 25,000
(organic soils)


TABLE 4. Guide for Determining Proper Plant Spacing
in Rows of Various Widths
Row Width (inches)
28 30 32 34 36 38 40
Plants/Acre1 Kernel Spacing in Drill (Inches)
10,000 20.1 18.8 17.7 16.6 15.7 14.9 14.1
12,500 16.1 15.1 14.1 13.3 12.5 11.9 11.3
15,000 13.4 12.5 11.7 11.1 10.5 9.9 9.4
18,000 11.2 10.5 9.8 9.2 8.7 8.3 7.8
20,000 10.1 9.4 8.8 8.3 7.8 7.4 7.1
25,000 8.1 7.5 7.1 6.6 6.3 5.9 5.6

1 Assuming that the final plant population will be 90 per-
cent of the planting rate, these kernel spacings are calcu-
lated to over-plant by 10 percent.







Nematode Control
Plant parasitic nematodes can cause significant
yield losses in corn in Florida. Nematodes feed
on plant roots, thus decreasing the plant's ability
to take up necessary plant nutrients and water.
Symptoms of nematode damage in field corn in-
clude growth reduction, thin stands, premature
wilting in dry weather and nutrient-deficiency
symptoms. Corn yields are lowered in direct rela-
tionship to the level of nematode infestation and
the amount of root injury. Typically, the pattern
of damage will appear in irregularly shaped pock-
ets greatly varied in size.
Two of the more important nematodes that at-
tack field corn are the sting and stubby root nema-
todes. These two nematodes are frequently found
in the light sandy soils of central and northern
Florida. Damage from sting nematodes can be
severe, particularly to young seedlings. It may
attack the germinating seed at the root tip pre-
venting its emergence, or it may stop the growth
of nearly all of the newly developing roots. Plants
may stand in the field for weeks without increas-
ing much in size. Other nematodes known to be
pathogens of corn include root-knot and lesion
nematodes.
Recent research has shown that sting nematodes
can, be economically controlled on field corn by
using nematicides. Results of experiments con-
ducted over a two year (1972-73) period in a
grower field near Alachua, Florida, showed that
corn treated with a nematicide produced 77 per-
cent more grain in 1972 and 46 percent more grain
in 1973 than untreated corn.

Application of Nematicides on Corn
Nematicides should be applied at planting with
a nematicide-insecticide applicator. Apply the
nematicide in a band approximately 12 inches wide
just in front of the planter shoe. If disk-openers,
shovels or sweeps are used to open a seed furrow,
the material should be placed behind the furrow
opener. Placing the nematicide in the seed fur-
row in contact with the seed is not recommended
since some phytotoxicity to the corn seedlings can
occur, particularly with Mocap 10G.
Treatment is suggested if corn is planted in a







field known or suspected to be infested with sting
or stubby root nematodes. Soil samples can be
used in diagnosing a nematode problem on field
corn. Contact the county Extension agent for de-
tails.
The nematicides listed in Table 5 are recom-
mended for use at the indicated rates of applica-
tion.

TABLE 5. Recommended Nematicides and Rates of
Application
Rate/1000 Linear Ft.
Rate/Acre in in 12-inch Band
Nematicidel 12-inch Band (Any Row Spacing)
40-inch Rows
Dasanit 15G 13.5 lbs. 14.5 oz.
Dasanit 6SC 1.3 pts. 1.6 fl. oz.
Furadan 10G 20 lbs. 1.5 lbs.
Mocap 10G 20 lbs. 1.5 lbs.
1 G= granular formulation, SC = spray concentrate formu-
lation.

Insect Control
Soil-borne insects, such as lesser cornstalk bor-
ers, wireworms and white grubs, can reduce yields
of field corn by feeding on developing seedlings,
causing stand reductions or making the plants
more susceptible to invasion by secondary disease
organisms. These insects may be controlled with
the insecticides listed in Table 6.
Control measures for other insects, cutworms,
budworms and aphids are also given. Generally
it is not economically practical to control these
insects with insecticides.

Weed Control
Weed control is essential for economical pro-
duction of field corn. Good rotations, adequate
cultivation, and proper use of herbicides will re-
duce weed problems.
Herbicides are effective and economical produc-
tion tools when properly used. First, identify the
weed problem and then select the herbicide pro-
gram to best control the weed problem. Season-
long weed control may require a program of more







field known or suspected to be infested with sting
or stubby root nematodes. Soil samples can be
used in diagnosing a nematode problem on field
corn. Contact the county Extension agent for de-
tails.
The nematicides listed in Table 5 are recom-
mended for use at the indicated rates of applica-
tion.

TABLE 5. Recommended Nematicides and Rates of
Application
Rate/1000 Linear Ft.
Rate/Acre in in 12-inch Band
Nematicidel 12-inch Band (Any Row Spacing)
40-inch Rows
Dasanit 15G 13.5 lbs. 14.5 oz.
Dasanit 6SC 1.3 pts. 1.6 fl. oz.
Furadan 10G 20 lbs. 1.5 lbs.
Mocap 10G 20 lbs. 1.5 lbs.
1 G= granular formulation, SC = spray concentrate formu-
lation.

Insect Control
Soil-borne insects, such as lesser cornstalk bor-
ers, wireworms and white grubs, can reduce yields
of field corn by feeding on developing seedlings,
causing stand reductions or making the plants
more susceptible to invasion by secondary disease
organisms. These insects may be controlled with
the insecticides listed in Table 6.
Control measures for other insects, cutworms,
budworms and aphids are also given. Generally
it is not economically practical to control these
insects with insecticides.

Weed Control
Weed control is essential for economical pro-
duction of field corn. Good rotations, adequate
cultivation, and proper use of herbicides will re-
duce weed problems.
Herbicides are effective and economical produc-
tion tools when properly used. First, identify the
weed problem and then select the herbicide pro-
gram to best control the weed problem. Season-
long weed control may require a program of more







than one herbicide, applied more than one time
and supplemented by timely cultivation to achieve
broad spectrum control. Properly timed post-
directed herbicides are usually necessary for late
season weed control in corn. Herbicides recom-
mended for use on field corn are shown in table 7.
Harvesting
Corn should not be combined until the grain is
physiologically mature. Most hybrids are mature
after the grain has dropped to 30% moisture. Al-
though harvesting at high grain moisture con-
tents, above 25%, reduces losses due to stalk and
root lodging and late season weed problems, the
grain will require extensive drying for safe stor-
age. Generally, harvesting corn when the grain
moisture content is between 17 and 24% is the
best compromise between harvesting losses and
drying costs.
Faulty combine adjustments can be a source of
considerable grain loss during harvest. One ear
per 25 feet of row or 60 kernels in a 40 by 40 inch
square represent a 3 bushel per acre loss. Follow
manufacturers recommendations for combine ad-
justments and adjust operating speed to prevail-
ing conditions.
Drying and Storing
Excess moisture is one of the greatest threats
to the safe storage of corn in Florida. For periods
of long storage (four months or longer), the safe
moisture level for shelled corn is 13%. The equi-
librium moisture content of shelled corn at 770 F
and 90% relative humidity is 19%. Since Florida's
climate is such that hardly a 24-hour period passes
without the relative humidity exceeding 90%, it
is easy to understand why storage of corn in Flor-
ida can be a problem.
Normally, moisture tends to migrate from the
center of the corn mass to the surface. This is
why spoilage is first noticed at the top of the stor-
age bid and at the side walls. Even though the
corn is at the correct moisture level when placed
in storage, it is certain that all the corn will not
remain at this level and provisions should be made
for removing excess moisture as it occurs.
The type of drying system selected will depend
upon several factors, such as (1) the total volume
10







than one herbicide, applied more than one time
and supplemented by timely cultivation to achieve
broad spectrum control. Properly timed post-
directed herbicides are usually necessary for late
season weed control in corn. Herbicides recom-
mended for use on field corn are shown in table 7.
Harvesting
Corn should not be combined until the grain is
physiologically mature. Most hybrids are mature
after the grain has dropped to 30% moisture. Al-
though harvesting at high grain moisture con-
tents, above 25%, reduces losses due to stalk and
root lodging and late season weed problems, the
grain will require extensive drying for safe stor-
age. Generally, harvesting corn when the grain
moisture content is between 17 and 24% is the
best compromise between harvesting losses and
drying costs.
Faulty combine adjustments can be a source of
considerable grain loss during harvest. One ear
per 25 feet of row or 60 kernels in a 40 by 40 inch
square represent a 3 bushel per acre loss. Follow
manufacturers recommendations for combine ad-
justments and adjust operating speed to prevail-
ing conditions.
Drying and Storing
Excess moisture is one of the greatest threats
to the safe storage of corn in Florida. For periods
of long storage (four months or longer), the safe
moisture level for shelled corn is 13%. The equi-
librium moisture content of shelled corn at 770 F
and 90% relative humidity is 19%. Since Florida's
climate is such that hardly a 24-hour period passes
without the relative humidity exceeding 90%, it
is easy to understand why storage of corn in Flor-
ida can be a problem.
Normally, moisture tends to migrate from the
center of the corn mass to the surface. This is
why spoilage is first noticed at the top of the stor-
age bid and at the side walls. Even though the
corn is at the correct moisture level when placed
in storage, it is certain that all the corn will not
remain at this level and provisions should be made
for removing excess moisture as it occurs.
The type of drying system selected will depend
upon several factors, such as (1) the total volume
10







of grain to be dried and capacity of the drying
equipment; (2) whether the corn is to be sold or
stored; and (3) degree of automation desired and
relationship of production locations) to drying
and/or storage facilities. Based on these factors
a bin drying system, portable batch drier or a
continuous flow drier may be selected. In most
cases a continuous flow drier will cost more initial-
ly and will be less efficient in relation to fuel
burned per bushel of corn dried than either of the
other type driers.
Corn harvested with more than 17% moisture
should be dried with heated air. Remove the grain
from the dryer at 16-17% moisture and place it in
aerated storage bins. With proper operation of
the aeration system, the moisture content of the
corn can safely be reduced to 15.5% for short term
storage or 13% for long term storage. Corn har-
vested at 17% moisture normally can be handled
in storage without the use of heat. It is impor-
tant to give strict attention to the operation of
the aeration system. When heat is used to dry
high moisture corn, optimum fuel efficiency will
be obtained if the temperature of the drying air
is not raised more than 20 degrees above the out-
side air temperature.
There is a tendency for corn-filled bins to sweat
on the inside, especially in winter. This condition
occurs when the temperature inside the bin is 15
degrees or more higher than the outside tempera-
ture. A good rule of thumb is to operate the
aeration fans whenever the outside temperature
is 10 or more degrees cooler than the corn tem-
perature. If moisture removal is desired, operate
the fans when the relative humidity of the outside
air is 65% or less. Operating the fans on a clear
day following a cold front is ideal. The direction
of air flow for aeration should be downward so
that warm moisture-laden air will be exhausted to
the outside, preventing condensation on the inside
of the roof which may fall back on the corn
causing spoilage.
The aeration fan should have a capacity of 1/4
to 1/2 cfm per bushel capacity of the bin. The
fan should deliver this volume of air at the max-
imum static pressure (S.P.) developed by the
stored corn. (This normally will be 1 to 3 inches






S.P. depending upon size of bin, moisture content
and depth of corn.) Aeration fans may be oper-
ated by a humidistat, thermostat, time clock or
combination of these controls. The poorest pos-
sible fan control is manual operation. It is too easy
to forget to turn the fan on or to turn it off
when it is running.
If a batch drying bin is used for corn storage
the drying fan may be used for aeration. Oper-
ating the fan two to three hours or longer, two
to three times per week on clear days when the
relative humidity is below 65 % is suggested. High
volumes of air moving upward through grain gen-
erally do not cause moisture to accumulate in the
top layers of grain.
The operator should have a moisture tester and
grain probe. All points of the bin should be
checked weekly (never over a month) for hot
spots and moisture build-up. If hot spots or
moisture spots are found, turn on the fans im-
mediately.
Control of Stored Grain Pests
Store properly dried grain in clean rat-proof
bins that easily can be made air-tight to permit
fumigation for control of insect pests.
To reduce insect population before storing grain,
clean bins thoroughly and spray walls, floors, and
ceilings to the point of "run off" (2 gallons per
1,000 square feet) with one of the following: 1
pint of 57 percent malathion EC (premium grade),
or 1 quart of 25 percent methoxychlor EC, or 1
pound of 50 percent methoxychlor WP in 3 gallons
of water.
If grain is not to be fumigated apply a protect-
ant and thoroughly mix it with the grain as it is
placed in the storage bins. Use one of the follow-
ing treatments: synergized pyrethrum (0.06 per-
cent pyrethrins, 1.0 percent piperonyl butoxide)
at the rate of 10 pounds per 100 bushels; malathi-
on dust (1 percent "premium grade" malathion in
special wheat flour dilutent) at the rate of 6
pounds per 100 bushels; or malathion spray (1
pint of 57 percent "premium grade" malathion
liquid concentrate in 5 gallons of water at the rate
of 1/2 gallon per 100 bushels.
Protective sprays and dusts applied to un-
shucked corn will suppress spread of weevils from
12







ear to ear, but will not control weevils within the
,unshucked ears.
Fumigation kills the insects present at time of
treatment, but does not provide protection against
reinfestation. For proper fumigation, bins must
be air-tight, and the temperature should be higher
than 70 F. Openly constructed storage struc-
tures should be lined with builders' paper before
grain is stored.
Immediately after filling of the storage facility
has been completed, level the surface of the grain,
close tightly all floor and wall vents, apply with a
sprinkler can or sprayer, one of the mixtures listed
below, spread a tarpaulin or plastic cover over the
surface after fumigant is applied, seal the door
and attach "DANGER" sign. After 72 hours,
open the door and vents and air the grain thor-
oughly.

Gals./1,000 Bushels of Grain
Fumigant Wooden Bins Steel Bins
1 part carbon
tetrachloride plus 3 parts
ethylene dichloride 8 6
4 parts carbon
tetrachloride plus 1 part
carbon disulfide 6 5

These and similar mixtures (one of which is a 60-35-5
mixture of carbon tetrachloride, ethylene dichloride and
ethylene dibromide) are available under various trade
names.

Another recommended fumigant is methyl bro-
mide, at the rate of 2 pounds per 1,000 cubic feet
of grain. To apply methyl bromide, place a pan or
other receptacle on the surface of the grain at the
center of bin, put the outer end of the tubing of
the applicator in the- receptacle and extend the
tubing to the outside of the bin, place an open
crate or other frame over the receptacle, spread a
plastic cover over the frame and grain surface,
seal door, release gas by use of the special appli-
cator, and attach "DANGER" sign. After 72
hours, open the door and vents and air the grain
thoroughly.
These fumigants are poisonous to man and
other warm-blooded animals. Read the label care-
fully, follow instructions and observe precautions.






TABLE 6. Recommended Insecticides and Rates of Application

Insects Material Amount/Acre Remarks


Budworms
Armyworms,
Corn Earworms


80% carbaryl WP
parathion 4E plus
toxaphene 8E
parathion + methyl
parathion 6-3E


1% lbs.
Y2 pt. plus
1% pts.

pt.


Apply to plant whorls. Spray should be directed to the upper leaves
to thoroughly wet and run down into the bud whorl. Control not recom-
mended unless more than 10% of the field is infested at tasseling.


40% chlordane WP
40% toxaphene WP
or
10% chlordane G
10% toxaphene G
2% chlordane B
5% Dylox B
21/2% toxaphene B


5 lbs.
5 lbs.

20 lbs.
20 lbs.
20-30 lbs.
20 lbs.
20-30 lbs.


Apply to soil surface before planting. Do not disturb for 3-5 days.





Use baits when damage appears.


Aphids m
pr


alathion 5E
irathion 4E


11/2 pts.
'/ pt.


Usually do not require control measures.


Cutworms


Wireworms, 14% diazinon G 28-42 lbs. If need for control is indicated use lower dosage on mineral soils
White Grubs 10% parathion G 20-50 lbs. higher on organic soils. Broadcast evenly over the soil surface two
to three weeks prior to planting and disc upper 6 inches of soil.






TABLE 6. Continued

Insects Material Amount/Acre Remarks
White-Fringed 10% chlordane G 50 lb. (Broad- Broadcast when preparing soil for planting and work into upper 3-4"
Beetles cast) of soil. May be applied alone or mixed with fertilizer.
10% chlordane G 20 lb. (Row)

Lesser Cornstalk 15% Dasanit G 13.5 lbs. Apply in a 12-inch band over the row in front of the press wheel at
Borers 10% Furadan G 20 lbs. planting time. No effective control measure after plants emerge.

Restrictions and Limitations
" carbaryl (Sevin), no time limitations; Dasanit, do not apply to plant foliage; Furadan (carbofuran), do not apply to plant foliage; mala-
thion, do not apply within 5 days of harvest or forage use; parathion, do not apply within 12 days of harvest or cutting for forage; toxa-
phene, do not feed treated forage to dairy animals or animals being finished for slaughter; trichlorfon (Dylox), do not use corn for food,
feed, or ensilage within 40 days of treatment.






TABLE 7. Herbicides Recommended for Use on Field Corn
Rate lb/A* Weeds Controlled
Herbicide Active Ingredient and Remarks


Preplant:
butylate (Sutan +)**


butylate (Sutan +)
+
atrazine (AAtrex)

Preemergence:
atrazine (AAtrex)



alachlor (Lasso)


alachlor (Lasso)
+
atrazine (AAtrex)


4



3 + 1.0



2-3



2-3



1.5 + 1.5


Annual grasses, some broadleaved weeds, nutsedge and Texas Panicum
are controlled. Incorporate immediately after application to a depth
of 3 to 4 inches.
Good broad spectrum control of annual grasses and broadleaf weeds.
Incorporate immediately after application to a depth of 3 to 4 inches.



Good broadleaf weed control but less effective on grasses. Lower rate
on light sandy soils. Under dry conditions a shallow cultivation may
improve control. Do not plant treated fields to crops other than corn
during the same season.
Provides good control of annual grasses and certain broadleaved
weeds. Use the lower rates on light sandy soils. Best results are
when rainfall occurs within 4-6 days after application.
Good broadspectrum control of annual grasses and broadleaved weeds.
The spectrum of weeds controlled is increased over either component
alone. See weeds controlled and remarks for each herbicide.






TABLE 7. Continued

Rate Ib/A* Weeds Controlled
Herbicide Active Ingredient and Remarks
cyanazine (Bladex) 2-3 Good control of annual grasses and broadleaved weeds. Best results
are when rainfall occurs within 4-6 days. Corn, soybeans or small
grains may be planted in rotation.


Postemergence:
2, 4-D Amine
(many tradenames)


Ametryn (Evik)



linuron (Lorox)


0.5



1.0 1.5



.75 1.5


Controls broadleaved weeds; cocklebur, pigweed, ragweed, morning-
glory and coffeeweed. Apply as directed spray to the base of the
corn plant, to minimize injury, after corn reaches 12 inches in height.
Avoid spray drift to near-by sensitive crops.
Good control of grasses and broadleaf weeds. Most effective if weeds
are less than 6" tall. Apply as a directed spray after the smallest
corn is at least 12" tall. DO NOT spray over top of corn. Add a
surfactant such as X-77 or DuPont WK.
Most grasses and broadleaved weeds up to 5 inches tall are controlled.
Apply as a directed spray after corn is 15 inches tall. Use lower
rate for 2-inch weeds and higher rate for 5-inch weeds. DO NOT
spray over top of corn. Use 1 pt. Surfactant WK for each 25 gal.
of spray mixture.


* Rates given on a broadcast basis. If a band treatment is used, reduce the rate proportionally. For example, if AAtrex is banded over
the row (12" band) in rows 36" apart, the rate used will be % of the rate indicated in the table.
** The common name of each herbicide is followed by the trade name in parenthesis.








Use of trade names in this publication is solely for the
purpose of providing specific information. It is not a
guarantee or warranty of products named and does not
signify approval to the exclusion of others if suitable
composition.




This guide was prepared by J. T. Johnson, Assistant
Agronomist; D. W. Jones, Agronomist; D. W. Dickson, As-
sistant Nematologist; W. L. Currey, Weed Specialist; J. R.
Strayer, Associate Entomologist; and T. C. Skinner,
Agricultural Engineer.


Single copies free to residents of Florida. Bulk rates
available upon request. Please submit details on
request to Chairman, Editorial Department, Institute
of Food and Agricultural Sciences, University of
Florida, Gainesville, Florida 32611.


6-10M-74







COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June'30, 1914)
Cooperative Extension Service, IFAS, University of Florida
and United States Department of Agriculture, Cooperating
Joe N. Busby, Dean


This public document was promulgated at an
annual cost of $754.82, or $.0754 per copy to
inform Florida ranchers and growers of field
corn production.




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