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 Table of Contents
 Determining defoliation timing...
 Peanut harvest timing and...
 Aminopyralid has been register...
 Tropical soda apple or just plain...
 Experimental use permits
 Reasons for crop rotations
 Schedule harvest for cotton and...


FLAG IFAS PALMM UF



Agronomy notes
ALL VOLUMES CITATION SEARCH THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00066352/00061
 Material Information
Title: Agronomy notes
Uniform Title: Agronomy notes (Gainesville, Fl.)
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.
Place of Publication: Gainesville
Creation Date: September 2005
 Subjects
Subjects / Keywords: Crops and soils -- Florida   ( lcsh )
Crop yields -- Florida   ( lcsh )
Agriculture -- Florida   ( lcsh )
Agronomy -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
periodical   ( marcgt )
serial   ( sobekcm )
 Notes
Statement of Responsibility: Florida Cooperative Extension Service, University of Florida, Institute of Food and Agricultural Sciences.
General Note: Description based on: January 1971; title from caption.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000956365
notis - AER9014
System ID: UF00066352:00061

Table of Contents
    Table of Contents
        Page 1
    Determining defoliation timing and defoliation materials in cotton
        Page 2
    Peanut harvest timing and grades
        Page 2
    Aminopyralid has been registered
        Page 3
    Tropical soda apple or just plain 'soda apple'?
        Page 3
    Experimental use permits
        Page 4
        Page 5
        Page 6
        Page 7
    Reasons for crop rotations
        Page 8
    Schedule harvest for cotton and peanut
        Page 9
Full Text





AGRONOMY
UNIVERSITY OF
FLORIDA NOTES
IFAS EXTENSION

September 2005






IN THIS ISSUE


COTTON
Determining Defoliation Timing and Defoliation
M materials in Cotton ..................................... ........ 2

PEANUTS
Peanut Harvest Timing and Grades .................................... 2

WEED CONTROL
Aminopyralid Has Been Registered ................................... 3
Tropical Soda Apple or Just Plain 'Soda Apple'? ......................... 3

MISCELLANEOUS
Experimental Use Permits .................................. ...... 4
Reasons for Crop Rotation ............... ........................ 8
Scheduling Harvest for Cotton and Peanut ............................. 9





The Institute of Food and Agricultural Sciences (IFAS) is an Equal Employment Opportunity Affirmative Action Employer authorized to
provide research, educational information and other services only to individuals and institutions that function without regard to race, color,
sex, age, handicap or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension
Office. Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / Larry Arrington, Interim
Dean.









Determining Defoliation Timing and
Defoliation Materials in Cotton

Defoliation timing is often based on percent
open bolls, nodes above cracked boll
(NACB) or heat unit accumulation after
cutout. Generally, once the NACB reaches
4 or if 60 to 70 percent of bolls are open,
cotton should be defoliated to prevent
quality loss from weathering.

There are many defoliants to choose from
and selecting the correct one can be
difficult. What works in one year may not
be very successful in another year due to
weather conditions, crop conditions or both.
Harvest aids can be classified as having
either a herbicidal or hormonal mode of
action. Herbicidal defoliants include
materials such as Def, Folex, Harvade and
Aim. Hormonal types include Dropp,
Leafless, Finish and Ginstar. Boll openers
are hormonal types that contain ethephon
and include materials such as Prep and
Cotton Quik. Since year to year variations
can alter the usefulness of either a hormonal
or herbicidal defoliant, a tank mix of the two
often achieve the most consistent results.
The most common program for Florida is to
use an herbicide defoliant along with a boll
opener 10-14 days before harvest.

D.L. Wright

Peanut Harvest Timing and Grades

One of the most critical parts of growing
peanuts is timing harvest to achieve
maximum grade and yield. Peanut grade
can tell a grower several things. Grading
begins by taking a measurement directly out
of the drying wagon. One test is for foreign
matter (FM), which denotes the amount of
plant material, rocks, or soil that is in a load
of peanut. FM is increased by digging when


soils are too wet or dry, or when peanuts
vines have not properly cured. FM can be
mitigated by adjusting the peanut combine
to blow more or less air to help reduce the
trash when harvesting. Another test is to
determine percent loose shelled kernels
(LSK), or the percent of peanuts that have
been shelled during the harvest process. A
high LSK may be due to high picker speed,
picker fingers being set too aggressively, or
too much air flow in the picker resulting in
rough handling within the machine.

Another sample is taken and shelled to
determine total sound mature kernels
(TSMK), sound splits (SS), other kernels
(OK), extra large kernels (ELK) and
damaged kernels (DK) on a percentage
basis. TSMK is the percent of peanuts that
are determined to be mature, while SS is the
percentage of seeds that are good, but split.
An OK value refers to the percentage of
kernels that may be immature or have other
defects. ELK refers to the percentage of
peanuts that ride over a certain screen size,
and are preferred by manufacturers for
candy production. Certain peanuts have a
tendency to have larger seed than others, but
growers are seldom paid for a high ELK
percentage. DK are kernels that are
damaged due to disease, insects or other
factors. Although all these values
contribute, overall grading is based mostly
on total TSMK values.

Digging peanuts too early can often result in
lower grades that range in the 60's and low
70's. Lower peanut grades also occur after a
drought during pegging. This is often
referred to as "two" crops of peanuts, with
one set early and one set later when
moisture returns. This makes it very
difficult to determine when to dig since you
would have some very mature peanuts along
with some very immature peanuts that were
set later. In irrigated peanuts, it is usually
easier to









Determining Defoliation Timing and
Defoliation Materials in Cotton

Defoliation timing is often based on percent
open bolls, nodes above cracked boll
(NACB) or heat unit accumulation after
cutout. Generally, once the NACB reaches
4 or if 60 to 70 percent of bolls are open,
cotton should be defoliated to prevent
quality loss from weathering.

There are many defoliants to choose from
and selecting the correct one can be
difficult. What works in one year may not
be very successful in another year due to
weather conditions, crop conditions or both.
Harvest aids can be classified as having
either a herbicidal or hormonal mode of
action. Herbicidal defoliants include
materials such as Def, Folex, Harvade and
Aim. Hormonal types include Dropp,
Leafless, Finish and Ginstar. Boll openers
are hormonal types that contain ethephon
and include materials such as Prep and
Cotton Quik. Since year to year variations
can alter the usefulness of either a hormonal
or herbicidal defoliant, a tank mix of the two
often achieve the most consistent results.
The most common program for Florida is to
use an herbicide defoliant along with a boll
opener 10-14 days before harvest.

D.L. Wright

Peanut Harvest Timing and Grades

One of the most critical parts of growing
peanuts is timing harvest to achieve
maximum grade and yield. Peanut grade
can tell a grower several things. Grading
begins by taking a measurement directly out
of the drying wagon. One test is for foreign
matter (FM), which denotes the amount of
plant material, rocks, or soil that is in a load
of peanut. FM is increased by digging when


soils are too wet or dry, or when peanuts
vines have not properly cured. FM can be
mitigated by adjusting the peanut combine
to blow more or less air to help reduce the
trash when harvesting. Another test is to
determine percent loose shelled kernels
(LSK), or the percent of peanuts that have
been shelled during the harvest process. A
high LSK may be due to high picker speed,
picker fingers being set too aggressively, or
too much air flow in the picker resulting in
rough handling within the machine.

Another sample is taken and shelled to
determine total sound mature kernels
(TSMK), sound splits (SS), other kernels
(OK), extra large kernels (ELK) and
damaged kernels (DK) on a percentage
basis. TSMK is the percent of peanuts that
are determined to be mature, while SS is the
percentage of seeds that are good, but split.
An OK value refers to the percentage of
kernels that may be immature or have other
defects. ELK refers to the percentage of
peanuts that ride over a certain screen size,
and are preferred by manufacturers for
candy production. Certain peanuts have a
tendency to have larger seed than others, but
growers are seldom paid for a high ELK
percentage. DK are kernels that are
damaged due to disease, insects or other
factors. Although all these values
contribute, overall grading is based mostly
on total TSMK values.

Digging peanuts too early can often result in
lower grades that range in the 60's and low
70's. Lower peanut grades also occur after a
drought during pegging. This is often
referred to as "two" crops of peanuts, with
one set early and one set later when
moisture returns. This makes it very
difficult to determine when to dig since you
would have some very mature peanuts along
with some very immature peanuts that were
set later. In irrigated peanuts, it is usually
easier to









determine proper digging date since
moisture can be supplied for a continuous
set of peanuts. However, other factors like
disease control and weather conditions can
affect digging date and yield. Vines should
be kept disease free as much as possible
since healthy vines will retain mature
peanuts better than dying, diseased vines.

Grades in the mid 70's are considered good
and often reflect that the grower properly
timed the digging. Digging peanuts a week
early or late can reduce yield by 500 lb/A,
costing the grower approximately $90, as
well as reducing grade by several points.
Improved grading of the crop also translates
into more income. A well timed harvest, or
properly set picker, can easily result in a
grade increase from 69 and 75 and a
produce a net gain by $25/ton. The key for
high yields and profit is to keep vines
healthy and dig on time.

D.L. Wright and H.E. Jowers

Aminopyralid Has Been Registered

Dow AgroSciences has received registration
for their first aminopyralid brand herbicide -
Milestone.

The U.S. Environmental Protection Agency
accepted the registration application for
Milestone herbicide on August 10, 2005.
Registration was received 14 months after
the original submission to the EPA, which is
less than half the time this process usually
requires. The rapid review and acceptance
was due to the toxicology profile of
aminopyralid, as well as for the fact that
aminopyralid controls several key weeds
(tropical soda apple, Canada thistle, and
knapweed, among others). Aminopyralid
will be sold as Milestone herbicide (2 lb
ae/gal) for control of invasive and noxious


broadleaf weeds in pastures, IVM,
roadsides, and other non-crop areas.
Registration in the state of Florida is
pending, but expected to occur quickly.

Another product to watch for is Forefront.
Forefront is a pre-mix product containing
aminopyralid + 2,4-D. In the near future,
this herbicide will also receive registration
and reach the marketplace.

Information on the use patterns and weed
control spectrum of these two products will
be provided in coming months.

J.A. Ferrell

Tropical Soda Apple or Just Plain 'Soda
Apple'?

Every now and then, you might see a plant
that looks much like tropical soda apple
(TSA), but something just does not look
right. Then you see the ripe fruit, and its
red, not the customary yellow or mottled
green like that of TSA. Most ranchers agree
that they have seen this red-fruited 'soda
apple' all their lives. In fact, there are two
soda apples in the state, TSA and just plain
'soda apple', or cockroach berry. For
simplicity, I will refer to the red-fruited soda
apple as cockroach berry in the rest of this
article. Both plants are native to South
America and are members of the nightshade
family.









determine proper digging date since
moisture can be supplied for a continuous
set of peanuts. However, other factors like
disease control and weather conditions can
affect digging date and yield. Vines should
be kept disease free as much as possible
since healthy vines will retain mature
peanuts better than dying, diseased vines.

Grades in the mid 70's are considered good
and often reflect that the grower properly
timed the digging. Digging peanuts a week
early or late can reduce yield by 500 lb/A,
costing the grower approximately $90, as
well as reducing grade by several points.
Improved grading of the crop also translates
into more income. A well timed harvest, or
properly set picker, can easily result in a
grade increase from 69 and 75 and a
produce a net gain by $25/ton. The key for
high yields and profit is to keep vines
healthy and dig on time.

D.L. Wright and H.E. Jowers

Aminopyralid Has Been Registered

Dow AgroSciences has received registration
for their first aminopyralid brand herbicide -
Milestone.

The U.S. Environmental Protection Agency
accepted the registration application for
Milestone herbicide on August 10, 2005.
Registration was received 14 months after
the original submission to the EPA, which is
less than half the time this process usually
requires. The rapid review and acceptance
was due to the toxicology profile of
aminopyralid, as well as for the fact that
aminopyralid controls several key weeds
(tropical soda apple, Canada thistle, and
knapweed, among others). Aminopyralid
will be sold as Milestone herbicide (2 lb
ae/gal) for control of invasive and noxious


broadleaf weeds in pastures, IVM,
roadsides, and other non-crop areas.
Registration in the state of Florida is
pending, but expected to occur quickly.

Another product to watch for is Forefront.
Forefront is a pre-mix product containing
aminopyralid + 2,4-D. In the near future,
this herbicide will also receive registration
and reach the marketplace.

Information on the use patterns and weed
control spectrum of these two products will
be provided in coming months.

J.A. Ferrell

Tropical Soda Apple or Just Plain 'Soda
Apple'?

Every now and then, you might see a plant
that looks much like tropical soda apple
(TSA), but something just does not look
right. Then you see the ripe fruit, and its
red, not the customary yellow or mottled
green like that of TSA. Most ranchers agree
that they have seen this red-fruited 'soda
apple' all their lives. In fact, there are two
soda apples in the state, TSA and just plain
'soda apple', or cockroach berry. For
simplicity, I will refer to the red-fruited soda
apple as cockroach berry in the rest of this
article. Both plants are native to South
America and are members of the nightshade
family.









Cockroach berry (Solanum capsicoides) is
an annual or short-lived perennial. In south
Florida, it likely survives as a perennial.
Cockroach berry can grow to heights of
approximately 3 feet, with numerous
prickles on stems, petioles, leaves and veins.
Leaves are as wide as they are long, may or
may not be lobed, and have a waxy
appearance. Upon inspection of the leaf,
scattered 1'/-inch long hairs can be seen.
Like TSA, cockroach berry is covered in
prickles on the stems, petioles, and both
sides of the leaves. The fruit is about the
size of a cherry tomato fruit, but are solid
green when immature and bright red at
maturity. The seeds are flat with a paper-
like wing that is a little less than 1/16 of an
inch wide, with the seed being a little
smaller than 1/8 of an inch in diameter.

TSA (Solanum viarum), as most of you
know, is a perennial plant that can grow
quite tall (up to 6 feet tall). TSA leaves
appear somewhat fuzzy due to glandular
hairs on the leaf surface. These glandular
hairs are found throughout the plant. If you
can touch the stem and leaves, while
avoiding the sharp prickles and spines, you
will be left with a sticky substance on your
hands. The fruit of TSA are a mottled green
when they are immature. The fruits are
yellow when ripe and emit a somewhat
sweet smell. The seeds inside the fruit are
brown and all seeds are covered with a
sticky, mucous-like substance.

A third plant, called sticky nightshade
(Solanum sisymbriifolium), also has red fruit
when mature. However, the leaves of this
plant are much more deeply lobed than
either cockroach berry or TSA.
Additionally, sticky nightshade leaves are
substantially longer than they are wide.
This plant is also armed with prickles, but
not as numerous as TSA or cockroach berry.


Cockroach berry and TSA, indeed, are quite
similar in appearance. Why is cockroach
berry then not the nuisance that TSA is?
Although not confirmed, it appears that
cockroach berry does not produce as many
seeds per fruit as TSA. Additionally, it is
not known if wildlife consume the fruits of
cockroach berry as they do TSA. Consider
also that TSA is a perennial, while
cockroach berry is considered an annual in
most environments. In most cases, seeing a
cockroach berry or sticky nightshade plant is
quite rare relative to finding a TSA plant. If
your pasture is infested with a large
population of cockroach berry, it is likely
that it can be controlled with the same
herbicides as TSA. Remedy at 2 pints per
acre has been the standard treatment for
TSA. Now, Milestone (aminopyralid), a
new herbicide that will be available in 2006,
will likely become the new standard for
TSA control at 5 to 7 fluid ounces per acre.

B.A. Sellers

Experimental Use Permits

Experimental use of pesticides refers to
formal research efforts conducted to
scientifically assess the pest control
potential of a registered pesticide or an
experimental pesticide. Experimental
pesticides include:

unregistered pesticides,

unregistered uses of registered
pesticides, and

pesticides or pesticide uses being
evaluated under an Experimental Use
Permit issued by the U.S. Environmental
Protection Agency (EPA) or by the
Florida Department of Agriculture and
Consumer Services (FDACS).









Compounds exempted from registration by
Section 25(b) of the Federal Insecticide
Fungicide and Rodenticide Act (FIFRA) are
not considered experimental pesticides.

The EPA may grant an Experimental Use
Permit (EUP) to researchers wishing to
gather data necessary to grant registration
under Section 3 of FIFRA for

a pesticide not registered with the
Agency, or
a new use of a registered pesticide (i.e.,
one not previously approved).

The EPA has determined an EUP is not
required when:

experimental work is limited to
laboratory or greenhouse tests, and
the researcher neither intends nor
confers pest control benefit to those
conducting it.

For limited replicated field (or other) tests,
conducted only to determine a chemical's
pesticidal potential, its toxicity, or other
properties, in which the persons conducting
the test do not expect to receive any benefit
in pest control from its use, the EPA has
determined that an EUP is not required for:

1. Land use The cumulative area
treated per site, per crop, per
experimental compound is less than 10
terrestrial acres (up to 250 acres for
pheromones), provided:

When testing for more than one
target pest occurs at the same time
and in the same locality, the 10-acre
limitation must encompass all of the
target pests.


Food or feed crops involved in or
affected by the tests (including crops
subsequently grown on this land, if
such crops may reasonably be
expected to contain residues of the
compound) must be destroyed or
consumed only by experimental
animals, unless an appropriate
tolerance or exemption from a
tolerance has been established.

2. Aquatic use Tests involving use of a
particular experimental compound are
conducted on a total of not more than
one surface-acre of water, provided:

When testing for multiple target pest
species occurs at the same time and
in the same locality, the one surface-
acre limitation encompasses all
target pest species.

The waters involved in or affected
by the tests will not be used for
irrigation, drinking water supplies or
body-contact recreational activities.

The tests may not be conducted in
waters which contain or affect any
fish, shellfish, other animals, or
plants taken for recreation or feed
unless an appropriate tolerance or
exemption from a tolerance has been
established.

3. Animal treatments Tests are
conducted only on experimental
animals. No animals receiving test
treatments may be used in food or feed
unless an appropriate tolerance or
exemption from a tolerance has been
established.









Important note Termiticides and
experimental pesticide applications in
structures do not fall under the land-use
exemption stipulations of federal and state
regulations. If unsure whether proposed
work is covered by the exemptions
described, contact FDACS.

FDACS adopted and upholds the federal
regulations that stipulate the conditions for
land use, aquatic use, and animal treatments
for which no experimental use permit is
required. These conditions are described
above.

Florida's adoption of the federal EUP
regulations notwithstanding, FDACS
imposes state-specific requirements for EUP
work that involves either unregistered
pesticides or unregistered uses of a
registered pesticide. There are three
circumstances where FDACS imposes
additional, state-specific requirements on
EUP work:

1. Research conducted in Florida under a
federal EUP must also be covered by a
state-issued EUP or EUP exemption.
The FDACS letter issuing the EUP (or
exemption) will reflect any additional
requirements (a copy may be obtained
from the EUP permit holder or
FDACS).

2. Where there is no federal or state-
specific EUP, and experimental uses of
pesticides are evaluated in small
replicated studies under the federal
land-use exemptions described above,
FDACS must be notified of
experimental trials conducted on
cumulative areas equal to or greater
than 1 acre but less than 10 acres, per
site, per crop, per experimental
compound. This notification must be


provided within 60 days of the
initiation of the trial and must include
the:

Name of the experimental compound
and its EPA registration number if
federally registered.

Name and mailing address of the
experimental compound's
manufacturer.

Activity of the compound (e.g.,
insecticide, herbicide, fungicide,
etc.)

Amount of experimental compound
used.

Total area treated including the
number of replicate applications.

Name of crop treated.Location of the
treated area.

Agency and contact person
responsible for the experimental use
study.

3. State-specific EUPs (where there is no
federal EUP). FDACS may issue a
state-specific experimental use permit
to:

Any person for the purpose of
gathering data necessary to support
FIFRA section 24(c) registrations.

Any agricultural research agency or
educational institution conducting
experimental use work within
Florida for any purpose not directly
intended to result in the registration
of a specific pesticide product.









Florida-specific EUPs are assigned a Florida
EUP number. These permits are issued with
an authorization letter that outlines the
requirements and restrictions for the Florida
EUP. In such cases, FDACS-approved EUP
labeling must be followed.
Somewhat relatedly, two additional points
merit mention:

Experimental use of aldicarb in Florida
must be authorized by the EPA or
FDACS.

FDACS should be consulted prior to
initiating experimentation involving
registered pesticides subject to
regulation under Florida's Organo-
Auxin Herbicide Rule.

UF/IFAS Policy on Experimental Uses of
Pesticides (this section applies only to those
employed by UF/IFAS)

1. Use of a pesticide under an EUP must
be consistent with the terms of the
EUP, including any additional
restrictions imposed by FDACS, and
the experimental protocol.

2. All food or feed derived from a
pesticide's experimental use must be
destroyed or fed only to experimental
animals for testing purposes, unless an
appropriate tolerance or an exemption
from a tolerance has been specifically
granted for residues of pesticide on the
food or feed crop(s).

3. An experimental pesticide may be
used only in accordance with its
experimental use permit or any
federally registered use permitted by
its labeling. If an experimental
pesticide does not have federally
registered uses, at the study's


conclusion, return any excess compound
to its original provider.

Pesticide Research and Demonstrations on
Non-UF/IFAS Property

Often, research or demonstration efforts
involving pesticide use require a site where
a particular target pest is present. To meet
this criterion, such work is sometimes
conducted on non-UF/IFAS property.
Whenever non-UF/IFAS property becomes a
site for pesticide-related research or
demonstration, UF/IFAS employees must
fully inform the property owner, cooperator,
or other party responsible for the land, about
the research or demonstration project's
pesticide chemical subjectss, its work
activity schedule, and its land use
requirements. The following policies
address these:

1. The project leader shall provide copies
of the research or demonstration plot
plans to the property owner,
cooperator, or other party responsible
for the non-UF/IFAS land.

2. The project leader shall inform the
property owner, cooperator, or other
party responsible for the non-UF/IFAS
land, if there will be crop destruction
requirements, grazing restrictions, or
crop rotation restrictions associated
with the research or demonstration
plots. He or she shall obtain a signed
agreement of understanding that the
property owner, cooperator, or other
party responsible for the non-UF/IFAS
land has received this information.
Copies of the signed agreement shall
be kept by the project leader and the
UF/IFAS unit and provided to the
property owner, cooperator, or other
party responsible for the non-UF/IFAS
land.









3. If the research or demonstration
project entails applying registered
pesticides to crop plants produced on a
farm, nursery, or greenhouse, the
project leader shall provide Worker
Protection Standard (WPS)
information about these pesticides to
the property owner, cooperator, or
other party responsible for the non-
UF/IFAS land. The project leader shall
ensure pesticide-specific WPS
information is provided before each
application of any registered pesticide
on the non-UF/IFAS land. The intent
is to both fulfill the federal rule and
make certain the property owner,
collaborator, or other party responsible
for the non-UF/IFAS establishment
can take appropriate measures to
properly notify his or her employees
about the upcoming pesticide
application. Accordingly, the project
leader shall provide:

The specific location and description
of the crop plants that are to be
treated with a pesticide.

The time and date the pesticide is
scheduled to be applied.

The trade name of the pesticide
product, its EPA registration
number, and the common name(s) of
its active ingredientss.

The restricted-entry interval for the
pesticide.

Whether the pesticide labeling
requires both treated-area posting
and oral notification.

Any other product-specific
requirements on the pesticide
labeling concerning protection of


workers and other persons during or
after applications.

4. The project leader shall also provide a
copy of an MSDS to the property
owner, cooperator or other responsible
party for each pesticide used on the
non-UF/IFAS land.

Additional Information

Pesticide Registrations:
Florida Department of Agriculture and
Consumer Services
Bureau of Pesticides
3125 Conner Blvd., (L-29)
Tallahassee, FL 32399-1650

F. Fishel

Reasons for Crop Rotation

Crop rotation is an important cultural
practice that has been shown to reduce the
effects of crop pests (disease, nematode,
insects, and weeds). In many cases, low
value crops are the only alternative for
rotating with high cash value crops like
peanuts. In other cases, good profitability is
possible, but crop rotation is not used due to
logistical problems (fencing, etc) or other
costs associated with production.

Extensive crop rotation research has been
conducted for most cropping systems and
the impacts of such rotations on pests have
been documented. Tomato spotted wilt
virus has become the main driving force
behind peanut variety selection and planting
date. After that, leaf spot is usually the most
critical aspect of peanut management that
must be considered. Leaf spot control is
usually accomplished with the use of a
chemical program, but there is much data
showing that rotation with cotton or corn
can










reduce the amount and severity of the
disease. Recent data shows that rotations
with bahiagrass can reduce leaf spot even
further while boosting peanut yields. In one
study, peanut yield was 19% higher after 2
years of corn and 41% higher after 2 years
of bahiagrass. Data from Georgia indicated
that growers often use shorter rotations
under pivots due to the large capital
investments required for irrigation systems.
However, when compared to continuous
peanut production with irrigation, a one,
two, and three year rotation under the pivot
resulted in a 7, 36, and 34% yield increase.
Under these same three rotation intervals,
peanut yield increased by 11, 25, and 28%
without irrigation compared to peanut grown
continuously without irrigation. Rotations
work, produce more profit, and reduce the
amount of management needed and capital
inputs.

D.L. Wright

Scheduling Harvest for Cotton and
Peanut

September is a critical time for growers in
the Southeast. Most of the heavy rains from
the summer are over and growers start
harvesting the crops that they sweated over


all spring and summer. However, the Deep
South has a tradition of harvesting peanuts
ahead of cotton. Even when cotton is ready
to defoliate, peanuts take precedent. Since
growers often make good yields with this
system of priority, timely harvest cotton has
not been as urgent as is necessary.

Southeast cotton quality has dramatically
decreased in recent years. Timely
defoliation and harvest is critical to keeping
the quality high and can make a difference
in market price. Late season hurricanes can
cause tremendous losses in lint and quality,
so some of growers will finish harvesting in
December knowing that quality has already
suffered. However, timely harvest is just as
important for cotton as it is for peanuts and
both should be managed to harvest on time.

D.L. Wright


The use of trade names does not constitute a guarantee or warrant of products named and does not signify approval to the exclusion of similar
products.
Prepared by: J.M. Bennett, Chairman; M.B. Adjei, Forage Agronomist (mbadjei@ifas.ufl.edu); J.A. Ferrell, Extension Agronomist
(jaferrell@ifas.ufl.edu); F.M. Fishel, Pesticide Coordinator (weeddr@ifas.ufl.edu); C.R. Rainbolt, Extension Agronomist
(crrainbolt@ifas.ufl.edu); B.A. Sellers, Extension Agronomist (sellersb@ifas.ufl.edu); E.B. Whitty, Extension Agronomist
(ebw@ifas.ufl.edu); D.L. Wright, Extension Agronomist (dlw@ifas.ufl.edu).