PLANT & SOIL SCIENCES FACT SHEET TOB-4-05
Alternative Sucker Control Methods
By Gary Palmer, Extension Tobacco Specialist
Sucker control in
Local systemic products include Prime+, Butralin,
and Flupro. Their mode of
control is localized to leaf axillary areas where contact is made with
actively growing sucker buds. Like
the fatty alcohols, they must come in contact with each sucker bud to be
effective. They do not burn
the sucker, but control sucker growth by stopping cell division in the
Local systemic products include Prime+, Butralin, and Flupro. Their mode of control is localized to leaf axillary areas where contact is made with actively growing sucker buds. Like the fatty alcohols, they must come in contact with each sucker bud to be effective. They do not burn the sucker, but control sucker growth by stopping cell division in the developing bud.
For jug applications or backpack sprayers, mix 2.5
fl oz per gallon and apply at approximately ½ to
⅔ fl oz per plant depending on crop the 20 to 25 psi range
not to exceed 30 psi. height.
Excessive spray mix that puddles on the ground below the plant
can have an adverse effect on the cover crop following the tobacco.
For tractor mounted or high clearance sprayers, applications can
be made using drop lines, over-the top using a three nozzle arrangement
or a straight boom with the same 2% solution. Each method has pros and
(Picture 2) generally provide the best control and consist of a line
running from the spray boom with a spray trigger and a coarse spray
nozzle that can be operated by a worker walking behind the sprayer.
The application rate should be between ½ and ⅔ fl oz per
plant but care must be used to prevent excess chemical from reaching the
ground to avoid cover crop injury. This
method provides more direct sucker contact and generally provides better
control, but is labor intensive and requires a slower pace to
accommodate workers. Practice
may be required for workers to become accustomed to the appropriate rate
of application. On tall
tobacco, missed suckers can be common in the top of the plant, but
misses are less common than in other methods.
nozzle arrangement has reduced labor requirements, requiring a spray
operator only, and provides the second best control.
Control, however, is dependent on good alignment of the spray
boom with the tobacco rows. This
method will provide better results on crops with uniform row spacing
particularly if that row spacing is similar to the spray boom nozzle
spacing. Solid cone
nozzles provide the best coverage and should be arranged so that a
higher spray volume nozzle is over the row and lower volume nozzles are
dropped slightly and directed toward the plant on either side of the
row. Nozzles such as
TG-5’s can be used over the row with TG-3’s direct toward the plant.
However, should the directed nozzles fall over the top of a row anywhere
along the boom, control may be reduced on those plants that get a reduce
amount of spray material. A
slight misalignment can result in a few misses in the tops of plants and
may require hand labor for removal and re-treatment of missed plants
using the jug or backpack method.
boom method provides more uniform coverage and is less dependent on
uniform rows, but may not provide the same level of control as the three
nozzle arrangement. The
straight boom has coarse nozzles spaced 19 to 20 inches apart for the
length of the boom. The boom
should be positioned approximately 18 inches above the crop.
Either TG-5 or TG-3 nozzles can be used for the entire length but
not both. Use TG-3’s for
tractor mount sprayers and for high clearance sprayers used on more
hilly terrain where traveling speeds are in the 2 ½ to 3 ½ mph range.
For high clearance sprayer on flatter ground where speed can be
increased to 4 to 5 mph, use TG-5’s or equivalent.
Re-treatment using the jug or backpack method may be necessary
where escapes occur. Treat
only the area where the sucker developed to prevent excessive residue in
the rest of the plant. Cover
crop damage should be less of a problem even though some of the chemical
may reach the ground.
The local systemic type sucker control chemicals
offer some benefits over MH-containing products other than reduced MH
residue. They provide
extended control which
can last for 5 to 7 weeks after application depending on weather,
growing conditions and crop requirements.
Rain occurring within 2 hour may reduce control.
Top leaves longer than eight inches treated with Prime+ or
Butralin tend to spread more than in plants treated with MH.
However, leaves less than eight inches in length could be
distorted by application of a local systemic.
Cured leaf color is usually darker than in plants treated with MH
since Prime+, Butralin, or Flupro cause bronzing in the tops of burley
plants unlike MH.
concerns do exist when using a local systemic for sucker control.
Escapes or missed suckers can grow uncontrolled if not addressed.
Escapes must be removed and re-treated.
Ground suckers will begin to grow again once the plant is topped.
Ground suckers too large for coverage by chemical rundown may
grow unchecked. Crops with
excessive ground sucker development may not be ideal candidates for a
Prime+, Butralin, or Flupro spray program.
Excessive spray volume can damage cover crops and a conscious
effort must be made to apply the correct amount to achieve complete
rundown that contacts each leaf axil without excess spray material
reaching the ground. Symptoms
of Prime+, Butralin or Flupro carryover in a cover crop includes a
reduced stand, purple leaves on grasses, and nubby roots on affected
fatty alcohols are a true contact type chemical that must contact the
small sucker bud causing a contact burn (Picture 3) which controls
sucker growth temporarily. Fatty
alcohols are marketed by several manufacturers and labels should be
followed closely for the specific product chosen.
Application can be made with either handheld, backpack, or power
driven equipment such as tractor mounted or high clearance sprayers.
Rates may vary but generally are in the range of 3 to 4% in volume.
A rate of 3% initially may provide better crop safety, but can be
followed by 4% later.
Pressure should be in the 20 to 25 psi not to exceed 30 psi.
The three nozzle arrangement over each row is recommended for
power driven equipment with a coarse nozzle such as a TG-5 or similar
nozzle over the row and two coarse nozzles such as TG-3 or similar
nozzles on a short drop on either side of the row directed in toward the
plant. Crops with irregular
row spacing may result in reduced control if the spray boom does not
align well with each row of plants.
Application of too little of the fatty alcohol could result in
reduced control while excessive rates can cause leaf damage.
Agitation before and during application is necessary to reduce
potential burn. Avoid
application during the middle of the day in hot weather to reduce leaf
burn. If the temperature
exceeds 90o F, leaf drop can occur.
Applications should not be made to tobacco that is wet from
rainfall or dew to avoid reduction in control.
Fatty alcohols can be applied either prior to or after topping. Any suckers longer than one inch should be removed prior to application in either case. Applications after topping should be made within two days of topping. Multiple applications may be needed and should be made prior to new sucker development. Failure to re-apply before sucker development exceeds one inch in size could lead to sucker control failure. Rainfall within one hour of application may reduce control.
Application of a fatty alcohols may improve sucker control if applied initially at the elongated bud stage at a 3% rate followed in five days by a combination of fatty alcohol at a 4% rate and any of the local systemics at the full rate. Adding a fatty alcohol to a local systemic may improve rundown of the local systemic and improve sucker bud contact.
crops that bloom irregularly may require special attention.
Plants that are blooming well in advance of the rest of the crop
should be topped, suckers removed by hand and treated with a fatty
alcohol or local systemic. If
considerable time occurs between toppings, a local systemic is advised
to prevent sucker re-growth. The rest of the crop can be treated with a
fatty alcohol or, if a fatty alcohol was used for the initial treatment,
Prime+, Butralin, or Flupro can be used for the second application.
Do not apply a local systemic to tobacco previously treated with
a local systemic.
or Leaning Tobacco
sucker control can occur in tobacco that is not in an upright position
due to weather or other reasons, since both types of chemicals require a
complete rundown that contacts all sucker buds.
Any sucker buds that do not come into contact with the chemical
will grow unchecked. In this
situation, treatment of individual plants using the drop line or
backpack method is more effective since the applicator can direct the
spray application to problem areas on each plant.