AGRONOMY

UNIVERSITY OF
FLORIDA NOTES
IFAS EXTENSION

April, 2005

IN THIS ISSUE

CORN
Aflatoxin Levels in Corn Grain ................ .......................... 2
Corn Planting Date and Pest Problems ................ ................... 2

COTTON
Strip Till Cotton or Peanut in Fallow Fields ................................. 2

FORAGE
Hay Producers ........................... ..................... ......... 2
Legumes That You Can Use to Overseed Your Pasture .......................... 3

PEANUTS
Peanut Contracts ............... .................................... 3
Planting Late Maturity Peanuts ............... ........................... 4

TOBACCO
Admire for Tobacco ..................................................... 4
Cucumber Mosaic Virus in Tobacco ................ ....................... 5
Tobacco Transition Payment Program ................................... 5

WEED CONTROL
A New 2,4-D Formulation .......
Reason for Herbicide Failure .......
Red Sorrel Biology and Control .....

MISCELLANEOUS
New Publication .................

. . . . . . . . . 5
. . . . . . . . . . 6
. . . . . . . . . . 7
.5 . . . .

. . . 8

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.

Aflatoxin Levels in Corn Grain

Contrary to what one might believe from
observing quality of grain from later planting
dates, late planting corn has less aflatoxin than
early planted corn. Grain quality usually
deteriorates as planting season is extended from
March into April, May and June. However,
aflatoxin usually peaks from April planted corn
for both tropical and temperate corn. This may
be due to the hot, dry conditions, which favor
Aspergillusflavus development, that occur when
corn is silking in late May. Corn planted in May
silks in June or early July when the humidity is
higher and aflatoxin levels are lower in the
grain. Bt (Bacillus ;lin,,, i,,g i ) corn did not
differ that much from non Bt corn but when it
did, it was always lower in aflatoxin than non Bt
corn and was significantly lower in some years.
Tropical corn with the tight shuck coverage did
not lessen the incidence of aflatoxin in the grain
and in one year of a three year study had
significantly more aflatoxin than temperate corn
planted in April. May and June planting dates of
corn exhibited low levels of aflatoxin in both
tropical and temperate corn with or without Bt.
Germplasm is being developed that has some
resistance to aflatoxin development and has been
under investigation at UGA's Tifton campus for
a number of years.

DLW

Corn Planting Date and Pest Problems

Several years of research data with many corn
hybrids has shown that higher fall armyworm
and corn earworm damage occurs with late
planting (May-July). Generally, much less
insect damage occurred on the Bt hybrids than
the non Bt, and it is very apparent in both silage
and grain yield. Little difference is noted in
corn planted in February through early April.
There is also a difference in hybrids in their
response to southern corn rust. Tropical corn
hybrids tested and recommended for Florida
have much less rust than temperate hybrids in
variety trials. This becomes more apparent with
late planting. However, there are differences in
rust tolerance of temperate hybrids and some
temperate hybrids do much better against

southern rust than others with late planting (late
April-June). Always get as much variety trial
information as possible from as many locations
and planting dates as possible before making
hybrid selection decisions.

DLW

Strip Till Cotton or Peanut in Fallow Fields

Questions arise about strip tilling into fields that
have not had crops grown for a few years.
There are usually many hard to control weed
species present including broom sedge and
horseweed as well as other broadleaf weeds.
Soils in these fields are often mellow in the top
few inches due to not being tilled or compacted
by equipment for several years. The question is
often asked if they can plant peanuts and dig
them without a problem. The answer is that
weeds need to be controlled before planting and
2,4-D is often necessary for some of the hard to
control weeds like horseweed and evening
primrose. Glyphosate or other similar materials
can be used to kill many other weeds a few
weeks before planting. The second answer is
that if the strip till rig can move through the field
at planting without dragging plant material and
gouging holes, the peanut plow should not have
a problem at harvest time.

Cotton planting depth is a little more critical
than peanut and the same principle applies as for
peanut, if the strip till rig leaves a smooth
seedbed at planting, there should be no problem
for planting cotton at the proper depth and with
weed control operations later in the season.

DLW

Hay Producers

"Don't get behind on your potassium
application". You might be surprised at the
amount of potassium that is removed from the
soil when hay is harvested and hauled off the
hay field. The table below gives estimates of the
amount of nutrients removed in various hay
crops.

Aflatoxin Levels in Corn Grain

Contrary to what one might believe from
observing quality of grain from later planting
dates, late planting corn has less aflatoxin than
early planted corn. Grain quality usually
deteriorates as planting season is extended from
March into April, May and June. However,
aflatoxin usually peaks from April planted corn
for both tropical and temperate corn. This may
be due to the hot, dry conditions, which favor
Aspergillusflavus development, that occur when
corn is silking in late May. Corn planted in May
silks in June or early July when the humidity is
higher and aflatoxin levels are lower in the
grain. Bt (Bacillus ;lin,,, i,,g i ) corn did not
differ that much from non Bt corn but when it
did, it was always lower in aflatoxin than non Bt
corn and was significantly lower in some years.
Tropical corn with the tight shuck coverage did
not lessen the incidence of aflatoxin in the grain
and in one year of a three year study had
significantly more aflatoxin than temperate corn
planted in April. May and June planting dates of
corn exhibited low levels of aflatoxin in both
tropical and temperate corn with or without Bt.
Germplasm is being developed that has some
resistance to aflatoxin development and has been
under investigation at UGA's Tifton campus for
a number of years.

DLW

Corn Planting Date and Pest Problems

Several years of research data with many corn
hybrids has shown that higher fall armyworm
and corn earworm damage occurs with late
planting (May-July). Generally, much less
insect damage occurred on the Bt hybrids than
the non Bt, and it is very apparent in both silage
and grain yield. Little difference is noted in
corn planted in February through early April.
There is also a difference in hybrids in their
response to southern corn rust. Tropical corn
hybrids tested and recommended for Florida
have much less rust than temperate hybrids in
variety trials. This becomes more apparent with
late planting. However, there are differences in
rust tolerance of temperate hybrids and some
temperate hybrids do much better against

southern rust than others with late planting (late
April-June). Always get as much variety trial
information as possible from as many locations
and planting dates as possible before making
hybrid selection decisions.

DLW

Strip Till Cotton or Peanut in Fallow Fields

Questions arise about strip tilling into fields that
have not had crops grown for a few years.
There are usually many hard to control weed
species present including broom sedge and
horseweed as well as other broadleaf weeds.
Soils in these fields are often mellow in the top
few inches due to not being tilled or compacted
by equipment for several years. The question is
often asked if they can plant peanuts and dig
them without a problem. The answer is that
weeds need to be controlled before planting and
2,4-D is often necessary for some of the hard to
control weeds like horseweed and evening
primrose. Glyphosate or other similar materials
can be used to kill many other weeds a few
weeks before planting. The second answer is
that if the strip till rig can move through the field
at planting without dragging plant material and
gouging holes, the peanut plow should not have
a problem at harvest time.

Cotton planting depth is a little more critical
than peanut and the same principle applies as for
peanut, if the strip till rig leaves a smooth
seedbed at planting, there should be no problem
for planting cotton at the proper depth and with
weed control operations later in the season.

DLW

Hay Producers

"Don't get behind on your potassium
application". You might be surprised at the
amount of potassium that is removed from the
soil when hay is harvested and hauled off the
hay field. The table below gives estimates of the
amount of nutrients removed in various hay
crops.

Aflatoxin Levels in Corn Grain

Contrary to what one might believe from
observing quality of grain from later planting
dates, late planting corn has less aflatoxin than
early planted corn. Grain quality usually
deteriorates as planting season is extended from
March into April, May and June. However,
aflatoxin usually peaks from April planted corn
for both tropical and temperate corn. This may
be due to the hot, dry conditions, which favor
Aspergillusflavus development, that occur when
corn is silking in late May. Corn planted in May
silks in June or early July when the humidity is
higher and aflatoxin levels are lower in the
grain. Bt (Bacillus ;lin,,, i,,g i ) corn did not
differ that much from non Bt corn but when it
did, it was always lower in aflatoxin than non Bt
corn and was significantly lower in some years.
Tropical corn with the tight shuck coverage did
not lessen the incidence of aflatoxin in the grain
and in one year of a three year study had
significantly more aflatoxin than temperate corn
planted in April. May and June planting dates of
corn exhibited low levels of aflatoxin in both
tropical and temperate corn with or without Bt.
Germplasm is being developed that has some
resistance to aflatoxin development and has been
under investigation at UGA's Tifton campus for
a number of years.

DLW

Corn Planting Date and Pest Problems

Several years of research data with many corn
hybrids has shown that higher fall armyworm
and corn earworm damage occurs with late
planting (May-July). Generally, much less
insect damage occurred on the Bt hybrids than
the non Bt, and it is very apparent in both silage
and grain yield. Little difference is noted in
corn planted in February through early April.
There is also a difference in hybrids in their
response to southern corn rust. Tropical corn
hybrids tested and recommended for Florida
have much less rust than temperate hybrids in
variety trials. This becomes more apparent with
late planting. However, there are differences in
rust tolerance of temperate hybrids and some
temperate hybrids do much better against

southern rust than others with late planting (late
April-June). Always get as much variety trial
information as possible from as many locations
and planting dates as possible before making
hybrid selection decisions.

DLW

Strip Till Cotton or Peanut in Fallow Fields

Questions arise about strip tilling into fields that
have not had crops grown for a few years.
There are usually many hard to control weed
species present including broom sedge and
horseweed as well as other broadleaf weeds.
Soils in these fields are often mellow in the top
few inches due to not being tilled or compacted
by equipment for several years. The question is
often asked if they can plant peanuts and dig
them without a problem. The answer is that
weeds need to be controlled before planting and
2,4-D is often necessary for some of the hard to
control weeds like horseweed and evening
primrose. Glyphosate or other similar materials
can be used to kill many other weeds a few
weeks before planting. The second answer is
that if the strip till rig can move through the field
at planting without dragging plant material and
gouging holes, the peanut plow should not have
a problem at harvest time.

Cotton planting depth is a little more critical
than peanut and the same principle applies as for
peanut, if the strip till rig leaves a smooth
seedbed at planting, there should be no problem
for planting cotton at the proper depth and with
weed control operations later in the season.

DLW

Hay Producers

"Don't get behind on your potassium
application". You might be surprised at the
amount of potassium that is removed from the
soil when hay is harvested and hauled off the
hay field. The table below gives estimates of the
amount of nutrients removed in various hay
crops.

Aflatoxin Levels in Corn Grain

Contrary to what one might believe from
observing quality of grain from later planting
dates, late planting corn has less aflatoxin than
early planted corn. Grain quality usually
deteriorates as planting season is extended from
March into April, May and June. However,
aflatoxin usually peaks from April planted corn
for both tropical and temperate corn. This may
be due to the hot, dry conditions, which favor
Aspergillusflavus development, that occur when
corn is silking in late May. Corn planted in May
silks in June or early July when the humidity is
higher and aflatoxin levels are lower in the
grain. Bt (Bacillus ;lin,,, i,,g i ) corn did not
differ that much from non Bt corn but when it
did, it was always lower in aflatoxin than non Bt
corn and was significantly lower in some years.
Tropical corn with the tight shuck coverage did
not lessen the incidence of aflatoxin in the grain
and in one year of a three year study had
significantly more aflatoxin than temperate corn
planted in April. May and June planting dates of
corn exhibited low levels of aflatoxin in both
tropical and temperate corn with or without Bt.
Germplasm is being developed that has some
resistance to aflatoxin development and has been
under investigation at UGA's Tifton campus for
a number of years.

DLW

Corn Planting Date and Pest Problems

Several years of research data with many corn
hybrids has shown that higher fall armyworm
and corn earworm damage occurs with late
planting (May-July). Generally, much less
insect damage occurred on the Bt hybrids than
the non Bt, and it is very apparent in both silage
and grain yield. Little difference is noted in
corn planted in February through early April.
There is also a difference in hybrids in their
response to southern corn rust. Tropical corn
hybrids tested and recommended for Florida
have much less rust than temperate hybrids in
variety trials. This becomes more apparent with
late planting. However, there are differences in
rust tolerance of temperate hybrids and some
temperate hybrids do much better against

southern rust than others with late planting (late
April-June). Always get as much variety trial
information as possible from as many locations
and planting dates as possible before making
hybrid selection decisions.

DLW

Strip Till Cotton or Peanut in Fallow Fields

Questions arise about strip tilling into fields that
have not had crops grown for a few years.
There are usually many hard to control weed
species present including broom sedge and
horseweed as well as other broadleaf weeds.
Soils in these fields are often mellow in the top
few inches due to not being tilled or compacted
by equipment for several years. The question is
often asked if they can plant peanuts and dig
them without a problem. The answer is that
weeds need to be controlled before planting and
2,4-D is often necessary for some of the hard to
control weeds like horseweed and evening
primrose. Glyphosate or other similar materials
can be used to kill many other weeds a few
weeks before planting. The second answer is
that if the strip till rig can move through the field
at planting without dragging plant material and
gouging holes, the peanut plow should not have
a problem at harvest time.

Cotton planting depth is a little more critical
than peanut and the same principle applies as for
peanut, if the strip till rig leaves a smooth
seedbed at planting, there should be no problem
for planting cotton at the proper depth and with
weed control operations later in the season.

DLW

Hay Producers

"Don't get behind on your potassium
application". You might be surprised at the
amount of potassium that is removed from the
soil when hay is harvested and hauled off the
hay field. The table below gives estimates of the
amount of nutrients removed in various hay
crops.

= Source Potash & Phosphate Institute.
SP205 = P x 2.29; P = P205 x 0.43.
K20 = K x 1.2; K = K20 x 0.83

The numbers in the table indicate that these hay
plants remove as much or more potassium
(K20) than nitrogen.

You may not want to add all of the potassium
that is indicated above, if your soil test is
medium or high in potassium. Plants can take
up and use some of the native potassium that is
in the soil. Follow soil test recommendations.

CGC

Legumes That You Can Use to Overseed
Your Pasture

Seed of three commonly used summer annual
legumes are available for planting in 2005.
These are aeschynomene (Aeschynomene
americana), alyceclover and hairy indigo.

These legumes can provide extra protein for
cattle during July, August and September when
pasture grasses may be low in protein.
Aeschynomene is adapted to wet flatwood sites,
and should not be planted on upland sands.
Alyceclover and hairy indigo can be planted on
flatwood sites with good drainage and on upland
sands. They do not like standing water. Since
all three are annuals, they are all susceptible to
establishment failure due to drought. Most

producers wait until the summer rains start
before planting. When overseeding an
established bahiagrass sod, be sure to graze it
short to reduce competition with the legume
seedlings. When legume seedlings are found,
remove the cattle in order to let the legume
plants develop. Start grazing when the legume
plants are 12 to 14 inches in height.

CGC

Peanut Contracts

Contract prices being offered for 2005 peanuts
are generally below those of last year.
Consequently growers need to be careful in the
level of inputs they use for the crop without
risking loss of yield. Be sure to follow a crop,
such as grass, corn, or cotton, that is not
susceptible to the same diseases and nematodes
as peanuts. Use soil tests to determine the
amount of lime, fertilizer, and gypsum that
would be needed for the crop. Select a variety
that produces high yields and has resistance to
the diseases that you expect on your farm.
Confirm with your contractor or expected buyer
as to an acceptable variety. Buy high quality
seed and protect it from damage during
handling, improper storage, or during planting.
Plant at a uniform depth of 1.5 to 2 inches on

Approximate pounds of nutrients removed by various forage crops at specified yield levels when
harvested as hay. 1

Species and assumed hay yield, tons/acre

Bermudagrass Alfalfa Sorghum-Sudan Tall fescue

----6 tons ---- ---- 5 tons ---- ---- 4 tons ---- ---- 3.5 tons ----

Nitrogen 258 280 160 135

Phosphate (P205) 2 60 75 61 65

Potash (K20) 3 288 300 233 185

Magnesium 18 25 24 13

Sulfur 30 25 25 14

= Source Potash & Phosphate Institute.
SP205 = P x 2.29; P = P205 x 0.43.
K20 = K x 1.2; K = K20 x 0.83

The numbers in the table indicate that these hay
plants remove as much or more potassium
(K20) than nitrogen.

You may not want to add all of the potassium
that is indicated above, if your soil test is
medium or high in potassium. Plants can take
up and use some of the native potassium that is
in the soil. Follow soil test recommendations.

CGC

Legumes That You Can Use to Overseed
Your Pasture

Seed of three commonly used summer annual
legumes are available for planting in 2005.
These are aeschynomene (Aeschynomene
americana), alyceclover and hairy indigo.

These legumes can provide extra protein for
cattle during July, August and September when
pasture grasses may be low in protein.
Aeschynomene is adapted to wet flatwood sites,
and should not be planted on upland sands.
Alyceclover and hairy indigo can be planted on
flatwood sites with good drainage and on upland
sands. They do not like standing water. Since
all three are annuals, they are all susceptible to
establishment failure due to drought. Most

producers wait until the summer rains start
before planting. When overseeding an
established bahiagrass sod, be sure to graze it
short to reduce competition with the legume
seedlings. When legume seedlings are found,
remove the cattle in order to let the legume
plants develop. Start grazing when the legume
plants are 12 to 14 inches in height.

CGC

Peanut Contracts

Contract prices being offered for 2005 peanuts
are generally below those of last year.
Consequently growers need to be careful in the
level of inputs they use for the crop without
risking loss of yield. Be sure to follow a crop,
such as grass, corn, or cotton, that is not
susceptible to the same diseases and nematodes
as peanuts. Use soil tests to determine the
amount of lime, fertilizer, and gypsum that
would be needed for the crop. Select a variety
that produces high yields and has resistance to
the diseases that you expect on your farm.
Confirm with your contractor or expected buyer
as to an acceptable variety. Buy high quality
seed and protect it from damage during
handling, improper storage, or during planting.
Plant at a uniform depth of 1.5 to 2 inches on

Approximate pounds of nutrients removed by various forage crops at specified yield levels when
harvested as hay. 1

Species and assumed hay yield, tons/acre

Bermudagrass Alfalfa Sorghum-Sudan Tall fescue

----6 tons ---- ---- 5 tons ---- ---- 4 tons ---- ---- 3.5 tons ----

Nitrogen 258 280 160 135

Phosphate (P205) 2 60 75 61 65

Potash (K20) 3 288 300 233 185

Magnesium 18 25 24 13

Sulfur 30 25 25 14

heavy soils and 2 to 3 inches on sands when soil
temperatures and moisture are favorable for
rapid germination and emergence. If tomato
spotted wilt virus is a threat in your area, be sure
to follow as many of the techniques as you can
for reducing losses to the disease. Know the
expected weed problems and plan to use
herbicides that will provide effective and
efficient weed control. Plan a disease control
program that provides application techniques
and timing that may provide for reduced costs,
while still keeping disease losses at a minimum.
Scout fields for insects, diseases, and weeds in
order to select products and timing of
application for best results. Use the hull-scrape
or peanut profile maturity method to predict the
optimum date to dig the peanuts. Use care to dig
and combine the peanuts to prevent excessive
losses in the field. Start drying the peanuts as
soon as possible after combining.

EBW

Planting Late Maturity Peanuts

Those peanut varieties considered to be late
maturity generally require 2 to 3 weeks longer to
mature, when planting at the same time, than the
more popular medium maturity varieties, such as
Georgia Green. The major advantage of the late
maturity varieties is that they have higher levels
of resistance to the major peanut diseases than
earlier maturity varieties, and currently are the
only varieties with significant resistance to leaf
spot. These varieties also have the highest levels
of resistance among all varieties to tomato
spotted wilt virus (TSWV), and with resistance
to white mold, rust, CBR, and other diseases.
Not only does this greater disease resistance
reduce losses to disease and therefore increase
the chance for a profit due to higher yields, but it
can also allow reduced costs of production as
fewer fungicide applications for prevention of
leaf spot would be required. Four fungicide
applications to the late maturity varieties grown
in a good rotation can provide as much leaf spot
protection as the 7 to 8 applications needed for

medium maturity varieties grown under the same
rotation. Despite these advantages the late
maturing varieties have had only limited
acceptance thus far by growers. Much of the
reluctance to grow these varieties has been due
to instances of poor germination and low vigor
during the early stages of growth, especially
with early planting. In many other instances
there were no problems with germination and
vigor. While all of the factors that contribute to
the germination and vigor problems are not
known, there are a number of practices that can
improve the chances for a successful crop. First
plant only good quality seed with a high
germination test score. Seed that were harvested
at full maturity, dried to 8 percent moisture, and
stored properly are believed to be especially
important to getting a good stand. A second
practice would be to plant in late April or early
May when soil moisture and temperatures are
conducive to rapid emergence and stand
establishment. Peanuts planted at this time
should mature in late September or early
October. Earlier planting could result in poor
germination and slow early growth, while later
planting would create a risk of getting full
maturity in the fall. Since these varieties require
150 or more days after planting to reach
maturity, a late May planting might not be
mature until late October or later. If cool and
dry weather occurs in October, maturity is
slowed and lower grades and yields may be
obtained.

EBW

Admire for Tobacco

The use of the systemic insecticide Admire in
the transplant water for tobacco has been shown
to reduce the incidence of tomato spotted wilt
virus (TSWV) in addition to control of aphids.
The reduced TSWV is not believed due to
control ofthrips, the insect that transmits
TSWV, but rather to a suppressing of the
symptoms of the disease. Generally the level of
TSWV suppression with Admire is considered
to be about 50 percent of the untreated. Admire
will normally provide aphid control until

heavy soils and 2 to 3 inches on sands when soil
temperatures and moisture are favorable for
rapid germination and emergence. If tomato
spotted wilt virus is a threat in your area, be sure
to follow as many of the techniques as you can
for reducing losses to the disease. Know the
expected weed problems and plan to use
herbicides that will provide effective and
efficient weed control. Plan a disease control
program that provides application techniques
and timing that may provide for reduced costs,
while still keeping disease losses at a minimum.
Scout fields for insects, diseases, and weeds in
order to select products and timing of
application for best results. Use the hull-scrape
or peanut profile maturity method to predict the
optimum date to dig the peanuts. Use care to dig
and combine the peanuts to prevent excessive
losses in the field. Start drying the peanuts as
soon as possible after combining.

EBW

Planting Late Maturity Peanuts

Those peanut varieties considered to be late
maturity generally require 2 to 3 weeks longer to
mature, when planting at the same time, than the
more popular medium maturity varieties, such as
Georgia Green. The major advantage of the late
maturity varieties is that they have higher levels
of resistance to the major peanut diseases than
earlier maturity varieties, and currently are the
only varieties with significant resistance to leaf
spot. These varieties also have the highest levels
of resistance among all varieties to tomato
spotted wilt virus (TSWV), and with resistance
to white mold, rust, CBR, and other diseases.
Not only does this greater disease resistance
reduce losses to disease and therefore increase
the chance for a profit due to higher yields, but it
can also allow reduced costs of production as
fewer fungicide applications for prevention of
leaf spot would be required. Four fungicide
applications to the late maturity varieties grown
in a good rotation can provide as much leaf spot
protection as the 7 to 8 applications needed for

medium maturity varieties grown under the same
rotation. Despite these advantages the late
maturing varieties have had only limited
acceptance thus far by growers. Much of the
reluctance to grow these varieties has been due
to instances of poor germination and low vigor
during the early stages of growth, especially
with early planting. In many other instances
there were no problems with germination and
vigor. While all of the factors that contribute to
the germination and vigor problems are not
known, there are a number of practices that can
improve the chances for a successful crop. First
plant only good quality seed with a high
germination test score. Seed that were harvested
at full maturity, dried to 8 percent moisture, and
stored properly are believed to be especially
important to getting a good stand. A second
practice would be to plant in late April or early
May when soil moisture and temperatures are
conducive to rapid emergence and stand
establishment. Peanuts planted at this time
should mature in late September or early
October. Earlier planting could result in poor
germination and slow early growth, while later
planting would create a risk of getting full
maturity in the fall. Since these varieties require
150 or more days after planting to reach
maturity, a late May planting might not be
mature until late October or later. If cool and
dry weather occurs in October, maturity is
slowed and lower grades and yields may be
obtained.

EBW

Admire for Tobacco

The use of the systemic insecticide Admire in
the transplant water for tobacco has been shown
to reduce the incidence of tomato spotted wilt
virus (TSWV) in addition to control of aphids.
The reduced TSWV is not believed due to
control ofthrips, the insect that transmits
TSWV, but rather to a suppressing of the
symptoms of the disease. Generally the level of
TSWV suppression with Admire is considered
to be about 50 percent of the untreated. Admire
will normally provide aphid control until

flowering, at which time the insect usually
becomes a minor problem. Flea beetles and
other insects are also controlled by Admire.

EBW

Cucumber Mosaic Virus in Tobacco

Cucumber mosaic virus (CMV) was identified
recently in a Florida tobacco plant bed. This
virus is spread by aphids and has been severe in
a few locations in recent years, but has not been
a common problem in most fields. However the
2004 infections were more widespread than in
the past, indicating that there could be many
more sites available for early infection in 2005.
There are a number of known cultivated plants
and weeds that serve as a host to CMV, and
perhaps many others that have not yet been
identified as hosts. It is possible that there will
be more cases reported over the next few
weeks.

EBW

Tobacco Transition Payment Program

The Tobacco Transition Payment Program
(TTPP) is the USDA's Farm Service Agency
(FSA) plan to provide payments to tobacco
quota holders and producers as a result of the
legislation commonly called the "Tobacco
Buyout" that was passed in October. To obtain
payments, eligible participants should sign
contracts at their local USDA Service Center by
June 17, 2005. If a producer grew tobacco in
more than one county, a contract must be signed
in each county. An eligible quota holder is one
that had a tobacco allotment assigned to his or
her farm on October 22, 2004, which is the date
the legislation became law. An eligible
producer is an owner, operator, landlord, tenant,
or sharecropper that shared in the risk of
growing tobacco in 2002, 2003, or 2004. Quota
owners will receive a total $7 per pound of basic
quota that was assigned to the farm in 2002,
with the payments being made annually for 10
years. Producer payments are for a total of $3
per pound of the 2002 effective quota, again
with the payments being in 10 equal payments
for 10 years. If there are multiple producers,

each share will be based on the information in
the form FSA-578, Report of Acreage, for each
of the three years, 2002, 2003, and 2004.
Producers may change the share percentages,
however all producers must agree with the
division. Lump-sum payments will not be paid
by FSA, but a participant may enter into an
agreement with a private party to receive a lump
sum in exchange for the annual payments. The
participant would need to sign a contract at the
FSA office to assign payments to the private
party. Further information can be obtained at the
FSA website: http://www.fsa.usda.gov/tobacco
or from the local FSA office.

EBW

A New 2,4-D Formulation

Amine and ester formulations of 2,4-D are
common and have been available for many
years. Recently, Helena Chemical Company has
developed and released, 'Unison', an acid
formulation of 2,4-D. In the past, practical use
of acid formulations of phenoxy herbicides was
limited due to water insolubility and formulation
problems. Helena has overcome these issues by
developing a system to dissolve insoluble auxin
acid in a water dispersible surfactant system.
The benefits of this technology are very low
volatility, low odor, 100% water solubility, and
100% liquid fertilizer compatibility.

Preliminary research indicates that when
comparing equal lbs acid equivalent, the acid
formulation has greater herbicidal activity than
amine formulations and is similar in activity to
ester formulations. It is important to note that
Unison is formulated at 1.74 lbs 2,4-D acid per
gallon, while most standard amine and ester
formulations contain 3.8 lbs 2,4-D acid per
gallon. Unlike some ester formulations, the acid
formulation of 2,4-D (Unison) complies with
Florida's Organo-Auxin Herbicide Rule.
Compared to standard 2,4-D formulations, there
is likely to be increased cost associated with this
new technology; however, it may be feasible to
use Unison when volatility and odor issues are
of concern.

flowering, at which time the insect usually
becomes a minor problem. Flea beetles and
other insects are also controlled by Admire.

EBW

Cucumber Mosaic Virus in Tobacco

Cucumber mosaic virus (CMV) was identified
recently in a Florida tobacco plant bed. This
virus is spread by aphids and has been severe in
a few locations in recent years, but has not been
a common problem in most fields. However the
2004 infections were more widespread than in
the past, indicating that there could be many
more sites available for early infection in 2005.
There are a number of known cultivated plants
and weeds that serve as a host to CMV, and
perhaps many others that have not yet been
identified as hosts. It is possible that there will
be more cases reported over the next few
weeks.

EBW

Tobacco Transition Payment Program

The Tobacco Transition Payment Program
(TTPP) is the USDA's Farm Service Agency
(FSA) plan to provide payments to tobacco
quota holders and producers as a result of the
legislation commonly called the "Tobacco
Buyout" that was passed in October. To obtain
payments, eligible participants should sign
contracts at their local USDA Service Center by
June 17, 2005. If a producer grew tobacco in
more than one county, a contract must be signed
in each county. An eligible quota holder is one
that had a tobacco allotment assigned to his or
her farm on October 22, 2004, which is the date
the legislation became law. An eligible
producer is an owner, operator, landlord, tenant,
or sharecropper that shared in the risk of
growing tobacco in 2002, 2003, or 2004. Quota
owners will receive a total $7 per pound of basic
quota that was assigned to the farm in 2002,
with the payments being made annually for 10
years. Producer payments are for a total of $3
per pound of the 2002 effective quota, again
with the payments being in 10 equal payments
for 10 years. If there are multiple producers,

each share will be based on the information in
the form FSA-578, Report of Acreage, for each
of the three years, 2002, 2003, and 2004.
Producers may change the share percentages,
however all producers must agree with the
division. Lump-sum payments will not be paid
by FSA, but a participant may enter into an
agreement with a private party to receive a lump
sum in exchange for the annual payments. The
participant would need to sign a contract at the
FSA office to assign payments to the private
party. Further information can be obtained at the
FSA website: http://www.fsa.usda.gov/tobacco
or from the local FSA office.

EBW

A New 2,4-D Formulation

Amine and ester formulations of 2,4-D are
common and have been available for many
years. Recently, Helena Chemical Company has
developed and released, 'Unison', an acid
formulation of 2,4-D. In the past, practical use
of acid formulations of phenoxy herbicides was
limited due to water insolubility and formulation
problems. Helena has overcome these issues by
developing a system to dissolve insoluble auxin
acid in a water dispersible surfactant system.
The benefits of this technology are very low
volatility, low odor, 100% water solubility, and
100% liquid fertilizer compatibility.

Preliminary research indicates that when
comparing equal lbs acid equivalent, the acid
formulation has greater herbicidal activity than
amine formulations and is similar in activity to
ester formulations. It is important to note that
Unison is formulated at 1.74 lbs 2,4-D acid per
gallon, while most standard amine and ester
formulations contain 3.8 lbs 2,4-D acid per
gallon. Unlike some ester formulations, the acid
formulation of 2,4-D (Unison) complies with
Florida's Organo-Auxin Herbicide Rule.
Compared to standard 2,4-D formulations, there
is likely to be increased cost associated with this
new technology; however, it may be feasible to
use Unison when volatility and odor issues are
of concern.

flowering, at which time the insect usually
becomes a minor problem. Flea beetles and
other insects are also controlled by Admire.

EBW

Cucumber Mosaic Virus in Tobacco

Cucumber mosaic virus (CMV) was identified
recently in a Florida tobacco plant bed. This
virus is spread by aphids and has been severe in
a few locations in recent years, but has not been
a common problem in most fields. However the
2004 infections were more widespread than in
the past, indicating that there could be many
more sites available for early infection in 2005.
There are a number of known cultivated plants
and weeds that serve as a host to CMV, and
perhaps many others that have not yet been
identified as hosts. It is possible that there will
be more cases reported over the next few
weeks.

EBW

Tobacco Transition Payment Program

The Tobacco Transition Payment Program
(TTPP) is the USDA's Farm Service Agency
(FSA) plan to provide payments to tobacco
quota holders and producers as a result of the
legislation commonly called the "Tobacco
Buyout" that was passed in October. To obtain
payments, eligible participants should sign
contracts at their local USDA Service Center by
June 17, 2005. If a producer grew tobacco in
more than one county, a contract must be signed
in each county. An eligible quota holder is one
that had a tobacco allotment assigned to his or
her farm on October 22, 2004, which is the date
the legislation became law. An eligible
producer is an owner, operator, landlord, tenant,
or sharecropper that shared in the risk of
growing tobacco in 2002, 2003, or 2004. Quota
owners will receive a total $7 per pound of basic
quota that was assigned to the farm in 2002,
with the payments being made annually for 10
years. Producer payments are for a total of $3
per pound of the 2002 effective quota, again
with the payments being in 10 equal payments
for 10 years. If there are multiple producers,

each share will be based on the information in
the form FSA-578, Report of Acreage, for each
of the three years, 2002, 2003, and 2004.
Producers may change the share percentages,
however all producers must agree with the
division. Lump-sum payments will not be paid
by FSA, but a participant may enter into an
agreement with a private party to receive a lump
sum in exchange for the annual payments. The
participant would need to sign a contract at the
FSA office to assign payments to the private
party. Further information can be obtained at the
FSA website: http://www.fsa.usda.gov/tobacco
or from the local FSA office.

EBW

A New 2,4-D Formulation

Amine and ester formulations of 2,4-D are
common and have been available for many
years. Recently, Helena Chemical Company has
developed and released, 'Unison', an acid
formulation of 2,4-D. In the past, practical use
of acid formulations of phenoxy herbicides was
limited due to water insolubility and formulation
problems. Helena has overcome these issues by
developing a system to dissolve insoluble auxin
acid in a water dispersible surfactant system.
The benefits of this technology are very low
volatility, low odor, 100% water solubility, and
100% liquid fertilizer compatibility.

Preliminary research indicates that when
comparing equal lbs acid equivalent, the acid
formulation has greater herbicidal activity than
amine formulations and is similar in activity to
ester formulations. It is important to note that
Unison is formulated at 1.74 lbs 2,4-D acid per
gallon, while most standard amine and ester
formulations contain 3.8 lbs 2,4-D acid per
gallon. Unlike some ester formulations, the acid
formulation of 2,4-D (Unison) complies with
Florida's Organo-Auxin Herbicide Rule.
Compared to standard 2,4-D formulations, there
is likely to be increased cost associated with this
new technology; however, it may be feasible to
use Unison when volatility and odor issues are
of concern.

For more information on the Florida Organo-
Auxin Herbicide Rule please refer to University
of Florida EDIS document SS-AGR-12 at
http://edis.ifas.ufl.edu

CRR

Reason for Herbicide Failure

Herbicide technology has improved dramatically
over the past 25 years. These products are now
safer and more effective than ever before.
However, herbicide failure is still a relatively
common occurrence. For example, have you
ever sprayed a herbicide fully expecting a
certain outcome, only to receive marginal levels
of control? Do your neighbors brag on
herbicides that you can't seem to make work on
your farm? Although herbicides seem to work
almost by magic, there are many factors that
impact herbicide effectiveness. Below are a few
of the more common scenarios.

Improper sprayer calibration: Many of our
herbicides are now applied at rates as low as a
few ounces per acre, rather than pounds per acre
as was common in the past. Considering these
low application rates, small discrepancies in
sprayer calibration can result in large differences
in amount of herbicide applied. For example, if
your target sprayer output is 15 gallons per acre,
but your actual output is 10 gallons, your
application rate of Cadre will reduced from
1.44 oz/A to 0.96 oz/A. Although Cadre
applied at 0.96 oz/A will still control a number
of weed species, other weeds such as hairy
indigo, large momingglory, Florida beggarweed,
and bristly starbur will not likely be controlled.
On the other hand, sprayer output that is greater
than expected will result in applying herbicides
at elevated rates. This will often lead to greater
herbicide cost and possible crop injury due to
improper application. Considering that the
sprayer calibration process requires little time to
perform, it is important to routinely check your
sprayer output to ensure that herbicide
application rates are not less, or more, than
required.

Drought at time of application: Postemergence
herbicides work by penetrating into the leaf and
then inhibiting some essential process within the
plant that eventually leads to plant death.
During periods of dry weather, plants will begin
to grow slowly and the leaves harden off in an
attempt to conserve water. This hardening off
process makes it much more difficult for
postemergence herbicides to enter the plant and
large portion of the chemical will dry on the leaf
surface without ever entering the plant.
Reduced herbicide uptake, of course, leads to
reduced levels of weed control. Conversely,
plants growing in areas of adequate soil moisture
are succulent, rapidly growing, and herbicide
penetration into the leaf is rapid and much more
effective. Therefore, applying herbicides in
times of hot, dry weather can be the reason for
herbicide failure. If possible, delaying herbicide
applications until the weeds are actively growing
can often lead to much greater levels of weed
control.

Adjuvants: The purpose of adjuvants (non-ionic
surfactants, crop oils, etc) is to improve
herbicide uptake into plant leaves. Non-ionic
surfactants work primarily by making the spray
droplet flatten out on the leaf surface, decreasing
evaporation time, and decreasing the potential
for the spray droplet to runoff the leaf. Crop oils
have many of the same properties as surfactants,
but they also help dissolve leaf surfaces and can
dramatically increase herbicide penetration into
the leaf. Omitting the proper adjuvant from the
spray tank can dramatically reduce the
effectiveness of many herbicides such as
Classic, Cadre, and Select.

Although there are several choices in the
adjuvant market, there are a few simple
guidelines to follow. Any non-ionic surfactant
that contains greater than 80% active ingredient
will work fine, generally, regardless of the brand
or price. However, some products will contain
surfactants, compatibility agents, buffering
agents, anti-drift agents, etc., all in one jug. But,
herbicide labels rarely, if ever, require the
addition of these products and their usage may

prove to be more costly and less effective.
Bottom line using the proper high quality
adjuvant at the proper rate can mean the
difference between excellent and mediocre weed
control.

Tank mixes: Tank mixing different herbicides is
a simple way to broaden the weed control
spectrum of any single herbicide. This is a
common practice in peanut weed control with
combinations such as Gramoxone + Basagran or
Cadre + 2,4-DB. Although tank mixing is
important in some situations, it is easy to get
carried away and add too many
herbicides/fungicides to the spray tank in an
attempt to control any conceivable pest. These
"Witch's Brew" combinations of herbicides can
often result in incompatibility in the spray tank
(herbicides may begin to fall out of solution) or,
more commonly, they result in herbicide
antagonism (reduces effectiveness). It is
important to note that not all herbicides work
well together. For example, Basagran is a good
herbicide that works well in peanut for broadleaf
weed control. However, the addition of
Basagran to Select, a commonly used grass
herbicide, can result in reduced grass control.
These products can be successfully used
together, but the application rate of Select
should be increased to compensate for the
antagonism of Basagran.

If you plan to tank mix different herbicides,
keep the combinations as simple as possible.
The addition of three or four herbicides and/or
fungicides to a single spray tank can often result
in antagonism and reduced herbicide
effectiveness. It is important to note that both
Select and Cadre are easily antagonized by many
different herbicides/fungicide combinations.

Conclusion: The herbicides we are currently
using in crop production are powerful and
highly effective, but they are not immune to
failure. Although the scenarios listed above are
some commonly observed reasons for lack of
herbicide performance, there are other situations
that affect weed control as well. Regardless,
being attentive to the environment and reading

the product label can dramatically improve your
chances of success.

JAF

Red Sorrel Biology and Control

We often see red when we look at our financial
situations, but we can also see red in our
pastures and along our roadsides right now. The
reddish hue we see is from a plant that is
currently flowering and setting seed. This plant
is commonly known as red sorrel, but other
common names include: sheep sorrel, sour-
grass, Indian cane, field sorrel, horse sorrel, sour
weed, red-top sorrel, cow sorrel, red-weed, and
mountain sorrel. Another common pasture
weed, curly dock, also has this characteristic
reddish hue, but this plant is a simple perennial
and spread is primarily by seed.

Red sorrel has a creeping root system and
spreads aggressively by underground roots and
rhizomes. The stem is somewhat woody at the
base of the plant and plant height ranges from
/2-foot to 2 feet tall, with little to no branching.
Lower-leaf blades are somewhat arrow-shaped
with one to two basal lobes. Upper leaves are
more slender and sometimes without these basal
lobes. Plants are dioecious (either male or
female), with male plants having orange-yellow
flowers and female plants with red-orange
flowers. Only female plants produce seed and
seed can remain viable for extended periods.
However, spread by seed is less extensive than
by the creeping rootstock.

Red sorrel is native to Europe, but it has become
adapted throughout the U.S. and southern
Canada. Presence of red sorrel in a pasture may
indicate low pH as this plant thrives under acidic
conditions, but it has adapted to other conditions
as well. Therefore, presence of the weed in a
pasture that has not been limed in many years
may necessitate a soil test.

Red sorrel control can be achieved with several
herbicides labeled for pastures. These
herbicides include Cimmaron, Banvel,

Weedmaster, Remedy, and Crossbow. Refer to
the latest recommendations (EDIS publication:
SS-AGR-08, Weed Management in Pastures and
Rangeland -2005) for specific rates and
precautions. Care should be taken to avoid
forage injury. Cimmaron should not be applied
to Pensacola bahiagrass and some injury could
be observed on other bahiagrass cultivars at
Cimmaron rates greater than 0.3 oz/acre.
Weedmaster contains 2,4-D and should not be
applied to limpograss pastures. Since red sorrel
is setting seed right now, it would be best to wait
until next year to spray a herbicide. Make a note
of the infested areas of your pasture and apply
your herbicide next January or February before
stem elongation begins.

BAS

New Publication

A new publication "Alfalfa The high-quality
hay for horses" can be obtained from the
following web site, www.alfalfa.org. A copy
can be down loaded and printed or hard copies
can be purchased. Although sponsored by the
"National Alfalfa Alliance"which promotes the
sale of alfalfa hay, the publication was written
by qualified university faculty and contains
valuable information about the use of alfalfa in a
horse's diet.

For example: 'NI thf The excess protein in
alfalfa hay will damage the kidneys. Reality:
Normal healthy horses can metabolize and
excrete the extra protein in alfalfa hay without
damaging their kidneys. However, horses
consuming high-protein diets may drink more
water and produce more urine as part of the
normal excretion process. All horses should
have access to clean water at all times."

CGC

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, C. G. Chambliss, Extension Agronomist; J.A. Ferrell, Extension
Agronomist, Curtis R. Rainbolt, Extenison Weed Agronomist; B.A. Sellers, Extension Weed Agronomist, E. B. Whitty, Extension
Agronomist, D. L. Wright, Extension Agronomist.

	Table of Contents
	Aflatoxin levels in corn grain
	Corn planting date and pest...
	Strip till cotton or peanut in...
	Hay producers
	Legumes that you can use to overseed...
	peanut contracts
	Planting late maturity peanuts
	Admire for tobacco
	Cucumber mosaic virus in tobac...
	Tobacco transition payment...
	A new 2, 4-D formulation
	Reason for herbicide failure
	Red sorrel biology and control
	New publication