Grain sorghum production guide

Material Information

Grain sorghum production guide
Series Title:
Wright, David L
Gorbet, Daniel W ( Daniel Wayne ), 1942-
Florida Cooperative Extension Service
Place of Publication:
Gainesville Fla
Florida Cooperative Extension Service
Publication Date:
Physical Description:
9, 1 p. : ; 28 cm.


Subjects / Keywords:
Sorghum ( lcsh )
Planting ( jstor )
Plants ( jstor )
Crops ( jstor )
government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )


General Note:
Cover title.
General Note:
"3-1.1M-85"--P. 10.
Circular (Florida Cooperative Extension Service) ;
Statement of Responsibility:
D.L. Wright and D.W. Gorbet.

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University of Florida
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20607741 ( OCLC )


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Copyright 2005, Board of Trustees, University
of Florida


Circular 346-B



Production Guide

D. L. Wright and D. W.

AUG 08 s 9S5


Grain Sorghum Production Guide

D. L. Wright and D. W. Gorbet*

Grain sorghum is second only to corn in feed
grain production in the U.S. Florida is a grain defi-
cient state and sorghum may help supply some of
the additional needed grain. Unfavorable weather
patterns have resulted in low corn grain yields and
a hesitancy for growers to produce it under dry-
land conditions. Rising production costs make it
essential to obtain satisfactory yields under a wide
range of conditions. Grain sorghum is a crop that
gives respectable yields even in years of periodic
drought. Sorghum may be planted over a longer
period than other commonly grown agronomic
crops and has moderate to good yield potential.
Grain sorghum is a versatile crop for multicropping
with wheat, and for rotation with soybeans and
may be planted as a single crop in April or in a
double-cropping system after small grains or after
corn under irrigation, and may be planted as late as
August 1. Fertility requirements for grain sorghum
are generally less than for corn.
In Florida, grain sorghum can provide some sup-
ply stability for livestock and poultry and can also
be used for alcohol production. Some varieties
(hybrids) of sorghum are available for use as high
tonnage silage, grazing, and sugar production.
Grain sorghum has produced well after small grain
under no-till conditions. Its main limitation has
been marketing. Grain sorghum may be a favorable
crop to grow if a stable market can be developed to
pay the producer. Its true value as a feed grain is
90 to 100% the value of corn.


Land Preparation- Sorghum may be planted
under conventional, minimum or no-till conditions.
With any planting method, a seedbed should be
adequately prepared to allow good soil-seed con-
tact and uniform seed distribution at the desired
depth. In-row subsoiling may be necessary on
many Coastal Plain soils to prepare the root bed.
The planter needs to be designed so that the subsoil
slot is sufficiently filled so that seeds are not planted
too deep. Sorghum seedlings are much less vigorous
than corn seedlings, and care needs to be taken
against deep placement, especially in cool soils.
Sorghum seed are small and, therefore, have little
stored food reserves and little ability to penetrate
crusted soil. Planting depth should range from 1
inch for clay soils to 11/ inches for sandy soils. Sor-
ghum should not be planted in a rough, cloddy
seedbed. Generally, emergence of a good hybrid

will be about 75% under good soil conditions and
65 to 75% under no-till conditions.

Planting Date

Soil temperatures for planting sorghum should
be near 65 to 700 F (at a depth of three inches
between 8:00 A.M. and 9:00 A.M.) for successful
germination and stand establishment. In Florida,
sorghum can usually be planted without damage
from cool soils or cold weather during the last
week of March or the first week of April. Earlier
plantings subject the slow growing sorghum seed-
lings to stand losses from frosts and competition
from weeds. Plantings can be made over a four
month period from the first of April until the first
week of August, after which there is danger that
sorghum will not mature before frost. For example,
after wheat is harvested a grower may wait several
days for adequate rainfall before planting sorghum
without lowering the yield potential.

Hybrid Selection

Many hybrids tested in Florida have high yield
potential when planted early. Hybrids used in the
southeastern Coastal Plain must have anthracnose
resistance. One of the highest yielding hybrids in
Florida trials for several years has been a bird resist-
ant hybrid which has a brown seedcoat or testa
(caused by high tannin content). However, bird-
resistant types do not have as high a feeding value
as non-bird-resistant types. Brown testa (seedcoat)
grain resist attack by fungi on maturing seeds in
our climate and also repel birds. White testa grain
hybrids are preferred for human food and milling
purposes and red grain is used mostly as livestock
and poultry feed.
The very early-maturing grain sorghum hybrids
are not adapted to our area primarily due to poor
disease resistance. Also, early season hybrids flower
sooner, have fewer leaves, develop smaller heads
and yield less than mid- or full season hybrids. Early
flowering and maturity limits plant size and grain
yield. Choice of maturity group for planting after
corn harvest is limited by days until frost and a
hybrid should be selected accordingly. Planting of
a hybrid earlier in the year should be dependent on
its relative performance, the availability of water
and nutrients, and time of appearance of insects
and diseases. The later maturing, higher yielding
hybrids that mature without encountering unfavor-
able growing conditions, insects, or disease should
be used. Early-maturing hybrids reach mid-bloom
in 50 to 60 days, medium early from 55 to 65
days, medium from 65 to 75 days, medium late

*D. L. Wright is Assistant Professor and Extension Agronomist, North Florida Research and Education Center, Quincy and D. W. Gorbet is
Associate Professor of Agronomy, Gainesville.

from 70 to 80 days, and full season hybrids, from
75 to 80 days depending on planting date and
growing conditions. Most high yielding hybrids in
Florida bloom 60 to 70 days after planting.
The commercial varieties are hybrids or crosses
between two or more parents. These seed cannot
be saved from one year to the next by the grower
and replanted with any expected degree of success.
HYbrid grain sorghums have increased yields a min-
imum of 25% over non-hybrids used before 1955.
However, most of the sweet sorghum varieties for
syrup are not hybrids and seed may be saved from
one year to the next for replanting.
One of the most recent advances in sorghum
breeding has been in developing midge resistant
hybrids. These varieties are new and not completely
proven but should be especially well suited for late
plantings following wheat or corn where midge
problems frequently occur.
Variety yield trials are conducted each year at
Jay, Marianna, and Ona. High yielding adapted
hybrids can be selected from these test results for
different locations.

Plant Populations and Row Width

Grain sorghum planted in 30 inch rows under
non-irrigated condition should have a plant popula-
tion of 45,000 to 70,000 plants per acre (about 2.5
to 4 plants per foot of row). With irrigation, popu-
lations can be increased to 70,000 to 120,000
plants per acre (4 to 7 plants per foot of row).
Row width of grain sorghum should generally be
30 inches or less. The slow developing characteris-
tics of grain sorghum make row widths of 20 inches
desirable when planted late so that a full canopy is
formed to shade row middles more quickly. Lower
plant populations should be used on sandy soils
subjected to periodic drought stress while higher
populations can be used on heavier soils and under

Water Requirements

Sorghum is the main feed grain crop in the warm
subhumid and semi-arid areas of the USA. Most of
the breeding work has been done in west Texas,
Nebraska, and Kansas where water is limiting. Sor-
ghum has been grown where rainfall is as low as 15
inches per year and July temperatures average as
low as 700 F. Because of its high resistance to des-
sication and performance under adverse conditions,
its use has spread into other areas of the country.
It is a valuable cash crop in these areas because of
its dependability under periodic drought stress.

Sorghum can make a crop on less water than
shown in Table 1. The critical period for water is
from the boot stage through the grain fill period, as
with most other crops. Total water requirements
for grain sorghum are almost as high as for corn
but its ability to tolerate short periods of drought
without totally losing the crop make it more attrac-
tive than corn when grown on sandy soils. Water
use for grain sorghum is low during the first four
weeks after emergence (about 0.07 inch per day)
and increases to about 0.25 inch per day from the
boot through the dough stage.

Table 1. Water use by grain sorghum when water is not limiting

Growth Water Use Cumulative
State Each Period Water Use

Emergence to 12" 4 4
12" to Boot 5 9
Boot to dough 9 Most Water Used 18
Dough to maturity 2 20

Grain sorghum planted after wheat in early June
will grow through the summer months (June, July,
and August) when afternoon rains are frequent and
be ready for harvest by mid-September to early
October, a notably dry period good for combining.
April planted grain sorghum may go through
periods of drought in April and May with wet con-
ditions in July at harvest time. Yields will generally
be higher from April than from June plantings if
moisture is adequate. Also plantings made in late
May through late July are more likely to be damaged
by midge and anthracnose.

Fertility Requirements
Crops have different nutritional requirements
for different yield potentials. The fertilizer pro-
gram should depend upon the type of cropping
sequence being followed, and whether multiple or
single cropping is done. All fertilizer programs
should be based on soil test results to maximize
potential for economic returns. A realistic yield
goal for non-irrigated grain sorghum in Florida is
70 to 120 bushels per acre. Although grain sor-
ghum hybrids have the potential to produce 150 to
200 bushels per acre, moisture limitations and
other environmental factors, usually reduce yields
to less than 50% of this potential. Fertilization of
P & K for grain sorghum based on soil tests of the
University of Florida is shown in Table 2. Nitrogen
is taken up in large amounts during the period of
rapid vegetative growth and during grain develop-
ment. Phosphorus uptake is high during early

growth and during grain development. Potassium
uptake is high during early growth and during grain
development. POtassium uptake is highest during
the vegetative growth period preceding heading.
Zinc and manganese are probably the most limiting
micronutrients in sorghum in the southeastern U.S.
Sorghum may need an application of 2 to 3 pounds
per acre of each nutrient where soil test levels are
less than 3 ppm for Zn and 12 ppm for Mn.
If nitrogen is adequate for vegetative growth,
but is limiting during grain formation, yield is re-
duced very little but the protein content of the
grain is usually reduced. Where more than adequate
amounts of nitrogen are available during grain for-
mation, endosperm protein may be exceptionally
high (12+%). Rates of nitrogen for grain sorghum
under dryland conditions should not normally ex-
ceed 120 pounds per acre applied in split applica-
tions (Table 3). Higher rates of nitrogen can be
used under irrigated conditions where yields are
expected to be higher.

Table 2. Rate of P205 and K20 fertilization of grain sorghum based
on soil tests (IFAS Extension Soil Testing, Meblich 1 extractable).
Yield goal is 120 bu/acre. Nitrogen fertilization rates of 120 Ibs

Element Soil Test Rating
v. low low medium high v. high

---------------pounds per acre-----------
Phosphorus 125 100 50 25 0

Potassium 125 100 50 25 0

1All P and K and 30 pounds of N are applied at planting. 120 Ibs of
N are sidedressed about 30 days after planting.

Table 3. Sorghum yields with different nigrogen and moisture
supply (New Mexico)

Nitrogen Low High
applied Rainfall Rainfall

Ibs/A ---------bu/A---------
50 75 78
100 80 93
150 74 121
200 66 156

Nitrogen deficiency in grain sorghum may limit
yields more than any other nutrient. Deficiency
symptoms appear as light green leaves and yellowing
from the bottom leaves up. Plants having adequate
N as well as other nutrients are also more drought

tolerant than those deficient in N. The grain head
paniclee) of sorghum develops early during plant
growth stages and (30 Ibs N/acre) must be applied
at planting to insure a high yield potential. The
remainder of the N (90-100 Ibs N/acre) should be
applied about days after emergence or by the time
the crop is 8 to 12 inches tall. By the time sorghum
heads emerge, approximately 60 days after plant-
ing, the plants have taken up almost 70% of their
total N needs. If sorghum shows need of additional
N at heading, an application of 30 to 40 Ibs N/A,
may be beneficial. If wheat or other small grain is
grown as the first crop in a multicropping system,
and heavy fertilizer applications were made, sor-
ghum may need only nitrogen and low levels of
other nutrients for high yields.
Phosphorus and potash may be applied in a band
2 to 4 inches from the row at planting or 6 to 8
inches below the seed so that the sorghum crop
will have access to high amounts of fertilizer even
with a limited root system without damage to the
seedling. If soil tests indicate medium to high
amounts of phosphorus, all of the phosphorus may
be broadcast on the small grain crop for both the
small grain and grain sorghum. With low to medium
soil test values, each crop should be fertilized indi-
vidually with the phosphorus being banded near
the row.
Starter fertilizer has been shown to be beneficial
for sorghum yields when planting in cold soils in
late March or early April. Surface applied preemer-
gence herbicide activity on sorghum is sometimes
poor and starter fertilizer helps sorghum outgrow
the weeds. Several experiments in the southeastern
U.S. on grain sorghum have shown twice as much
vegetative growth and 7 to 10 days earlier maturity
than those without starter fertilizer. Starter fertili-
zers (usually 10-34-0 as a liquid or 18-46-0 as a
granular, but could be 10-20-0 or others) are gen-
erally applied at a rate of 70 to 100 Ibs/A near the
row in a band or below the seed. Care should be
taken when using potassium or nitrogen fertilizers
in the furrow because germination can be reduced.
The percentage of nutrients taken up in different
periods is shown in Table 4.

Table 4. Percent nutrient uptake in each period by grain sorghum
(New Mexico)

Nutrient Weeks after Emergence

0-3 3-6 6-9 9-12 12 maturity
------------% Uptake-------------
N 5 33 32 15 15
P205 3 23 34 26 14
K20 7 40 33 15 5

Weed Control

Probably the weakest link in grain sorghum pro-
duction in the Southeast is grass control. Although
sorghum's growth habit and nutrient requirements
are much like corn, many of the herbicides available
for corn cannot be used on grain sorghum. The
limited herbicides and application methods available
for grain sorghum make the weed control program
critical. Early weed control in sorghum is essential
for high yields. Under no-till conditions, weeds
present at planting must be controlled or they may
exceed growth of the sorghum, requiring use of
shield post-directed spray application as the only
means of weed control.
Broadleaf weeds can be controlled in sorghum
by use of 2, 4-D or other labeled broadleaf material.
However, it can cause some injury to the plant by
inhibiting root development, causing brittle stalks,
leaf curling, height variability, and reducing yields.
Applications of 2, 4-D are less likely to injure sor-
ghum when it is from 4 to 10 inches tall than at
other stages.
Atrazine with oil has been applied over the top
of sorghum when sorghum is in the three-leaf stage
(Table 5). Other herbicides are available for pre-
emergence application as published yearly in
"Weeds in the Sunshine". Activity of these surface
applied herbicides is dependent on water to activate
them in the top inches of the soil. Post-directed
spray equipment is an excellent way to control
weeds in sorghum at the earliest possible stage to
prevent further yield reduction. Cultivations may
be used in conventional plantings where row spac-
ings permit.
With continuous no-tillage systems, low soil pH
can be critical to herbicide activity from continuous
surface applications of N fertilizers. A soil pH of
5.5 or lower in the top 2 inches of soil can drastically
reduce the effectiveness of herbicides.

Insect Control

A number of insects can cause economic yield
loss to grain sorghum. Of these, there are five that
may be considered as major pests. They include the
lesser cornstalk borer, fall armyworm, corn ear-
worm, sorghum webworm, and sorghum midge.
Other pests that can cause problems are cutworms,
aphids, grasshoppers, chinch bugs, and stink bugs.
The lesser cornstalk borer is primarily a pest on
sorghum seedlings less than 10 inches tall. However,
the lesser cornstalk borer can also damage larger
plants. This pest is a particularly severe problem in
soybeans following small grains and on sandy and/
or dry soils.

The fall armyworm and corn earworm can feed
both in the whorls of young plants and on the
developing grain in sorghum heads. In the whorl
stage, these pests are very difficult to control. If
insecticide applications are needed, they should be
made by ground equipment with nozzles directed
into the whorl delivering 25+ GPA at low pressure.
Sorghum can tolerate considerable vegetative
loss (25 35%) without significantly affecting grain
In addition to the fall armyworm and the corn
earworm, the sorghum webworm also feeds in the
head. It causes sporadic problems on grain sorghum,
particularly late in the season. (August October).
The sorghum midge is a very small fly that is
usually more difficult to detect than the other
insects mentioned and can cause heavy damage to
grain sorghum. Grain sorghum can be attacked by
the midge during flowering. Under normal growing
conditions, this period usually lasts 10 to 15 days.
During this period, heads should be checked for
adult midge every 2-3 days. When the midge popu-
lation averages Vs to 1 midge/head, treatment is
Many insect problems on grain sorghum can be
reduced or eliminated entirely by planting early.
Early-planted grain sorghum can be harvested before
high populations of the major insect pests are pres-
ent in mid-to late summer. Hybrid selection may
also aid in reducing insect pest problems. Generally
the open-head hybrids allow better penetration of
insecticides resulting in better control and better
field drying than on hybrids with compact heads.
Infestations of these pests vary from season to
season and from one field to another so it is impor-
tant to check fields regularly and apply control
measures only when necessary. Current recommen-
dations for control of insect pests may be found in
"Sorghum Insect Control" Entomology Report
#68. Control measures for many common sorghum
insects are shown in Table 6.
Many of the same nematodes that reduce yields
in corn and other grass crops will reduce grain sor-
ghum yields. Sorghum has been grown on a limited
basis in Florida and little nematicide yield response
information is available. Sorghum makes an excel-
lent crop to use in rotation with soybeans or other
broadleaf crops. Nematicides currently recom-
mended are shown in Table 7.

Disease control in sorghum is accomplished
mainly by use of resistant hybrids, crop rotation,
bottom plowing, clean cultivation, chemical seed

treatment, and by insect control, which decreases
injury sites for plants to become infected. Several
common sorghum diseases are anthracnose, grey
leaf spot, mosaic, bacterial stripe and others. These
diseases are reduced by using newer resistant
Sorghum seed not treated with fungicides may
rot, or seedlings may damp off or remain unthrifty.
Seedlings of grain sorghum are not very vigorous,
so most seeds are treated before being sold to the
public. Where good quality treated seeds may ger-
minate 85% of the amount planted, 50 to 70% of
untreated seeds may germinate. Care should be
taken to buy only fungicide treated seeds.


Most of the grain sorghum hybrids have been
developed for yield, shortness, head drying, and
threshability. Grain sorghum is physiologically
mature when the most immature seed reach about
35% moisture and can be satisfactorily combined
when the grain moisture is 20 to 25%. Harvesting
at high moisture results in cracked grain or un-
threshed heads. More trash may be found in com-
bined grain sorghum than any other harvested grain.
Many green stems from the grain heads may be har-
vested with the seed. This trash can increase mois-
ture in the seed by 2 to 3% in the time that sor-
ghum is being transported from the field to the
dryer. Therefore, the combine should be adjusted
so that all the grain is threshed and separated from
the head with minimum cracking and as little trash
is left in the grain as possible. Usually combine
adjustments are made so that most of the grain is
threshed from the head with some cracking of the
grain. Excessive cracking or too many unthreshed
seed should be corrected. Field drying to 15%
moisture is possible in a dry fall but early harvest is
usually critical due to mold growth and shattering
as the grain dries down. If sorghum is to be stored,
it should be dried down to 11 to 12% moisture like
other grains.

Ratoon Cropping

Ratoon cropping means harvesting more than
once from a single planting of a crop. Grain sor-
ghum can be ratoon cropped in the southeastern
United States by planting in April and harvesting in
late July to 25% grain moisture. After harvest the
sorghum is cultivated or sprayed to control weeds,
sidedressed with 60 to 80 pounds of N, and cut to
a height of 4 to 6 inches with a sicklebar mower. A
rotary mower can be used, but it shatters the stem
more than the sicklebar mower and may result in

reduced stands. Regrowth of new shoots or tillers
come from basal buds on the remaining part of the
stem at ground level. Normally the forage yield of
the second crop will be about 75% of the first crop
and grain yields range from 30 to 70% of the first
grain crop. This method of cropping makes for an
inexpensive second crop of grain, even though
grain yields may not be very high. Insects are usually
much more severe on the second crop, increasing
the need for close scouting.
After the grain is harvested, the stem and leaf
portions can be harvested for forage as long as
applied pesticide labels do not prohibit such use.


There is an important relationship between grain
temperature and moisture content and the time
grain can be held in storage before mold develop-
ment and insect activity become a problem. The
temperature range associated with these problems
is often prevalent during sorghum harvest in Florida,
unless the sorghum is planted late and harvested
after frost in December.
Several types of equipment are available for dry-
ing grains. Sorghum dries slower than corn and the
volume of grain sorghum that can be dried in each
batch is less than for corn. Most existing drying
facilities will have been set up for corn, and the
same method of drying may be used for grain sor-
ghum. The drying time for grain sorghum should
be the same as for corn but with 1/4 to 1/3 less
grain being dried each time. Where trash is excep-
tionally heavy in sorghum, decrease the grain load
by 40% of that used for corn.
When drying sorghum for seed, as in the case of
sweet sorghum, the temperature should be 1000F
or less. However, no commercial hybrid of grain
sorghum should be saved for seed. Where sorghum
is to be used for feed, temperature of 1400F can
be used for batch-in-bin systems using 10 to 25
cubic feet of air flow per minute per bushel (cfm/bu).
Temperatures to 2000F may be used in batch or
continuous flow dryers with 100 to 200 cfm/bu air
flow. Drying of grain in deep layers should be
avoided as moisture may condense in the top layer
resulting in molding.
Trash in grain sorghum can be a fire hazard dur-
ing drying and causes increased resistance to air
movement. Dryers should be inspected both before
and after drying a batch to make sure that no areas
are clogged that could result in a fire. Dryers should
not be run unattended for long periods of time. All
air intake areas can be covered with a screen not
finer than 1/ inch mest to keep trash from being
carried through the flame. Grain sorghum seed is

Table 5. Weed control in sorghum.1

Trade name and Common name and
rate of commercial rate of active ingredient
product per acre per acre Remarks

Dual 8E
(1.5-2.0 pts)
(2.5-3.0 qts)
(several formulations)
(1.5 pts)
(2.0 qts)
(several formulations)
Igran 80W
(2.5 Ibs)
Dual BE
(1.5 pts)

(1.5-2.0 Ibs)
2.5-3.0 Ibs)
(2.0 Ib)
(1.5 Ibs)

Use on Concep-treated seed.2 If seed Is not properly treated with Concep, injury will occur. Good control of many
grass and certain small seeded broadleaf weeds.
Use on Screen-treated seed.3 If seed is not properly treated with Screen, injury will occur. Good control of many
grass and certain smell seed broadleaf weeds.
For control of broadleaf weeds. Apply at planting before crop or weed emerge. Do not use on sand, or loamy sand
See comments for each herbicide above.

(2.0 Ibs)

(1.0 Ib)
(2.0 Ibs)
(1.5 Ibs)

See comments for propezine above.

See comments for each herbicide above.

(1.5 Ibs)

Aatrex or Atrazine
(several formulations)

2, 4-D
Several brands
(.5 pt)
Lorox 50 WP
(1-2 Ibs)
Lorox 4L
(1-2 pts)
Lorox + 2, 4-D
Ortho Paraquat
CL or Gramozone
(1-2 pts)

(1.2 Ibs)

(1.2 Ibs)

2, 4-D
(.5 Ib)
(.25 Ib)
(.5-1 Ibs)

(.25-.5 Ib)

Apply after sorghum reaches the 3-leaf stage and before broadleaf weeds are 4 inches tall. For ground applications
add emulsifiable oil at 1-gal per acre or oil concentrates at 1-qt per acre. Do not use on sand or loamy sand. Do not
graze or feed forage for 21 days following applications.
Broadleaf weeds. Broadcast after sorghum is 6-10" tall. If sorghum is taller than 10", use drop nozzles to direct
spray toward base of plant. Do not treat sorghum in boot, tassel, or soft dough stage. Avoid drift.
Broadleaf weeds. Apply 10-25 days after sorghum emergence. Application later than 25 days may reduce yields.
Do not graze or feed treated sorghum, forage or silage prior to mature grain stage. Avoid drift.
Grass and broadleaf weeds. Apply as a directed spray when sorghum is a minimum of 12 inches tall and weeds are
no more than 4 inches tall. Do not allow spray to contact upper sorghum leaves or whorl. Add surfactant WK at 2
qts per 100 gel of spray. Do not graze or feed plants to livestock within 3 months after application.

Tank-mix for improved broadleaf weed control. See rates and remarks for each herbicide above.
Grass and broadleaf weeds. Apply as a directed spray when sorghum is a minimum of 12 inches tall and weeds are
less than 3 Inches tall. Do not spray higher than 3 inches on sorghum plant. Add Ortho X-77 surfactant at 1 qt per
100 gal of spray.

STeem, D. H., W. L. Currey, and B. J. Brecke. 1983. Weed control in sorghum In "Weeds in the Sunshine" A-83-8.
2Concep, manufactured by Ciba-Geigy Corp., is a seed protectant which Is applied to sorghum seed to minimize injury when the herbicide Dual is used on sorghum for weed control.
3Screen, manufactured by Monsanto, is a seed protectant which is applied to sorghum seed to minimize injury when the herbicide Lasso is used on sorghum for weed control.

Table 6. Insect control in sorghum.

Insect Insecticide Rate/A Min. Days to Harvest

carbaryl (Sevin) 80 WP
chlorpyrifos (Lorsban) 15G
chlorpyrifos (Lorsban) 4 E
diazinon AG 500
diazinon 14G
(do not apply directly to the seed furrow
as reduction of sorghum seed germination
may occur)

methomyl (Lannate, Nudrin) 1.8 L
methomyl (Lannate, Nudrin) 90 SP
mevinphos (Phosdrin) 4 E
parathion 4 E

2% Ibs.
8 oz/1000 row ft.
1-2 pts.
2-4 qts.
14-28 Ibs.

21 for grain no limit for forage

1 pt. 30, > 1 pt. 60
broadcast preplant incorp.
preplant incorp.

1-2 pts.
.-% Ibs.
1 pt.
%-1 pt.

carbaryl (Sevin) 80 WP
chlorpyrifos (Lorsban) 4E
parathion 4E

carbaryl (Sevin) 80 WP
chlorpyrifos (Lorsban) 4E
methomyl (Lannate, Nudrin) 90 SP
methomyl (Lannate, Nudrin) 1.8 L
mevinphos (Phosdrin) 4E
parathion 4E

1 %-2y lbs.
1-2 pts.
%-1 pt.

1%/-2% Ibs.
1-2 pts.
%-Yg Ibs.
1-2 pts.
%-1 pt.
%-1 pt.

21 for grain no limit for forage
1 pt. 30, > 2 pt. 60

21 for grain no limit for forage
1 pt. 30, > 1 pt. 60


lesser cornstalk borer

sorghum midge

chlorpyrifos (Lorsban) 4 E
dimethoate (Cygon) 4 EC
malathion 91% ULV tech.

chlorpyrifos (Lorsban) 15 G
chlorpyrifos (Lorsban) 4 E
diazinon 14 G

carbaryl (Sevin) 80 WP
diazinon AG 500
(Ethion) 4 E

%-1 pt.
1 pt.
8 fl. oz.

4-12 oz./1000 row ft.
1-2 pts.
7-14 Ibs.

1 7/8 Ibs.
%-1 pt.
%-1 pt.

1 pt. 30, > 1 pt. 60
10 inch band at planting

21 for grain no limit for forage
7 grain-forage may be fed immediately to livestock



fall armyworms


_*I corn earworm


Table 6. Insect control in sorghum.

Insect Insecticide Rate/A Min. Days to Harvest

malathion 91% ULV tech. 8-12 fl. oz. 7 grain sorghum only
methomyl (Lannate, Nudrin) 1.8 L 1-2 pts. 14
methomyl (Lannate, Nudrin) 90 SP %-%/ Ibs. 14
dimethoate (Cygon, Defend) 4 EC -% pts. 28 Apply during bloom period in 2-10 gal. water/A
carbophenothion (Trithion) 4 E Y pt. Do not graze or cut for forage within 21 days
chlorpyrifos (Lannate) 4 E % pt. 30
parathion 4 E 1-2 pts. 12

sorghum webworm methomyl (Lannate, Nudrin) 1.8L 2 pts. 14
methomyl (Lannate, Nudrin) 90 SP / lb. 3
chlorpyrifos (Lorsban) 4 E 2 pts. 60
parathion 4 E %-1 pt. 12

stink bugs carbaryl (Sevin) 80 WP 1%-22 Ibs. 21 for grain no limit for forage
parathion 4 E 1-1% pts. 12

webworms carbaryl (Sevin) 80 WP 11-2% Ibs. 21 for grain no limit for forage
mevinphos (Phosdrin) 4 E %-1 pt. 3

Cautions: Often under certain climatic conditions and on some varieties of grain sorghum organophosphate chemicals may cause leaf discoloration.
Organophosphorous pesticides recommended in this publication: parathion, Phosdrin, trithion, ethion, demethoate, malathion, diazinon.

Table 7. Nematode control for sorghum.

Ounces/1000 ft Approximate pounds of product
Product of row per acre for various row spacings

36" 30" 24" 20"
Furadan 10G 12.0 10.0 13.1 16.3 19.6
Furadan 15G 8.0 7.3 8.7 10.9 13.1
Counter 15G 8-16 7.3-14.5 8.7-17.4 10.9-21.8 13.1-26.0

Warning do not assume that nematicides which have been successfully used on field corn can automatically be used successfully on sorghum.
For instance, sorghum is extremely sensitive to Mocap residues, even though Mocap may be used safely and effectively on corn.

usually cleaned by sifting the grain through a screen
or sieve, leaving the trash on top. Most cleaners are
designed to retain the seed and drop the fines.
Extreme caution should be taken when holding
high moisture grain ahead of the dryer. When grain
moisture is near 25% and grain temperature 800 to
900F, heating and mold problems may occur rapidly.
Air circulation is much less in grain sorghum than
in corn and heat builds up rapidly.


Grain dried to 11 or 12% and stored in metal
bins can spoil due to moisture migration, insects
and mold. Moisture migration is caused by grain
and air cooling near the sides of the bins. Cool air
is heavier than warm air and falls to the bottom of
the bin forcing warm air up through the middle of
the grain. When the warm air meets the cool air at
the top of the bin, condensation occurs leaving
moisture on the top center layer of grain. This is
where mold and insects can be a problem. This
moisture migration and molding can be eliminated
with aeration by drawing the cool air down through
the grain, discharging the warm moist air outside
and reversing the natural trend of warm air rising.
Fans should not be operated when fog, rain, and
high humidity exist. In late fall and winter, fans
can be operated during the day when humidity is
below 60%.
If fans are set up to aerate grain by forcing air
upwards, higher air volumes are necessary than
with downward aeration, forcing warm air com-
pletely out of the grain. Periodic inspection of the
grain is necessary for proper aeration and to prevent
spoilage and insect damage.
Sorghum can also be stored as high moisture
grain (+25%) in an oxygen-limiting container and
utilized in that manner. This eliminates the need
for drying but requires specialized equipment for
storing and handling.

Utilization of Grain Sorghum

The entire plant of grain sorghum can be utilized.
If no pesticides have been applied to the sorghurii
plant that prohibit grazing or utilization of the for-
age for silage, green chop, or hay, it may be har-
vested in this manner after combining the grain.

When grain sorghum is planted late and harvested
near frost, cattle should be kept off the stubble 5
to 7 days after a hard killing frost to avoid prussic
acid poisoning.
Sorghums are classified into different groups
according to their use. Table 8 shows how they are
generally used.
Nutrient composition of corn and sorghum plants
are similar. However, corn has a higher grain con-
tent and, therefore, slightly higher levels of crude
protein and a lower content of crude fiber than
sorghum forage. When cutting sorghum for silage,
the protein content is higher at the soft dough
stage with maximum tonnage at the hard dough

Table 8. Sorghum classification and use.

Type of Green chop
Sorghum Pasture or hay Silage Syrup Grain

Johnsongrass X X
Sudangrass X X X
and Sudangrass
Sorghum-Sudan X X X
grass hybrids
Sweet sorghum X X
Forage sorghums X X X
Combine type
Grain sorghum X X X

Generally kernels of grain sorghum varieties are
larger and have a higher starch content than those
of forage or syrup varieties. However, dry weather
can decrease seed size, increase protein conten,
and lower starch content of all varieties.
Forage sorghums are more desirable for silage
than grain sorghum types due to the higher sugar
content of stems and higher dry matter production.
Quality of feed from sorghym depends on whether
the grain (high quality), silage (medium quality), or
stubble (low quality) has been harvested.
Grain sorghum is a crop to be considered for
grain in multicropping programs because of its
adaptability of being planted with other crops and
its resistance to yield decreases with periods of

Fu5 E fir!".

This publication was produced at a cost of $727.73, or 66.2 cents per copy, to instruct Florida farmers in improved
sorghum production. 3-1.1M-85

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residents from County Extension Offices. Information on bulk rates or copies for out-of-state purchasers Is available from
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