THE WEED PATCH
Prowl H2O: A New Prowl Formulation
Jim Griffin
A new formulation of Prowl herbicide is being marketed in the sugarcane growing areas.
The new formulation, Prowl H2O, is water based as compared with the Prowl EC
(emulsifiable concentrate) formulation which is oil based. For the EC formulation an
emulsifier is added that allows the herbicide to be mixed with water without separating
out. In contrast, the new formulation is micro-encapsulated where the herbicide is coated
with a polymer. Micro-encapsulation allows the herbicide to be suspended in water and
eliminates the need for an emulsifier. The advantage to micro-encapsulation of Prowl is
that both odor and staining are reduced. Another key difference between the
formulations is that Prowl H2O does not have to be incorporated if rainfall is not received
within 7 days after application. The new formulation of Prowl is a 3.8CS (capsule
suspension) and contains 3.8 lbs active ingredient per gallon, which means that it is
slightly more concentrated than the 3.3EC formulation which contains 3.3 lbs active
ingredient per gallon. To convert rates, divide the Prowl EC rate by 1.15 to calculate the
Prowl H2O rate. Where 4 pts/A of Prowl EC is used you will apply 3.5 pts of Prowl H2O.
The cost per gallon of Prowl H2O is greater than Prowl EC, but remember that a gallon of
the micro-encapsulated formulation will treat more acres, so always calculate the cost on
a per acre basis.
We have tested the new micro-encapsulated Prowl formulation applied both at planting
and in spring and when applied at the same rate of active ingredient per acre as the EC
formulation, weed control and sugarcane response was the same. Most definitely the
odor is reduced with the micro-encapsulated formulation. When we used a plastic
graduated cylinder to measure Prowl H2O, the plastic did not stain and was easily rinsed.
For your information I have included below the recommendations from the LSU
AgCenter Sugarcane Weed Control guide for use of Prowl at layby, in fallowed fields,
and at planting.
Where Prowl is a component of a growers weed control program, use of the new Prowl
H2O formulation should be considered especially when residential areas, businesses,
schools, or hospitals are adjacent to treated fields. The increase in cost associated with
the new formulation compared with the older EC formulation may be offset by reduced
complaints due to odor.
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Dr. Jim Griffin is with the LSU AgCenter in the Department of Agronomy and
Environmental Management and has research and extension responsibilities in the area of
sugarcane weed management. Results from sugarcane weed control research and specific
sugarcane weed control recommendations can be viewed at
www.lsuagcenter.com/weedscience under “Related Publications”.
LSU AgCenter Recommendations - Prowl and Prowl H2O in Sugarcane
Layby Recommendations:
Rate of Formulated
Material for 1 Acre
Broadcast
Prowl 3.3EC,
Pendimax 3.3EC
2.4 – 3.6 qt
OR
Prowl H2O 3.8CS
2.1 – 3.1 qt
Weeds Controlled
Remarks
Seedling johnsongrass,
itchgrass, browntop panicum,
and other annual grasses
May be surface applied or soil incorporated. Use higher rate if
surface applied or if itchgrass is a problem. Aatrex/Atrazine,
Direx/Karmex, DuPont K-4, Sencor, or Spartan may be applied
to the soil surface for broadleaf weed control. Application of
these herbicides could be delayed to extend the period of
residual weed control. Add nonionic surfactant or crop oil
concentrate if weeds are present. Prowl H2O is a capsule
suspension (micro-encapsulated) formulation with less staining
and odor compared with the EC formulation. Prowl H2O does
not have to be incorporated if rainfall is not received within 7
days after application.
Fallow Recommendations:
Rate of
Formulated
Material for 1
Acre Broadcast
Prowl 3.3 EC
3.0 qt
OR
Prowl H2O 3.8CS
2.6 qt
Weeds Controlled
Remarks
Seedling johnsongrass,
itchgrass, browntop
panicum, other annual
grasses
Apply to clean seedbed at least 60 days prior to planting. Deep
incorporation (4 inches) by plowing or rotary tiller will increase the
control of rhizome johnsongrass and bermudagrass. Atrazine,
Direx/Karmex, or DuPont K-4 may be applied preemergence for
broadleaf weed control. Prowl H2O is a capsule suspension (microencapsulated) formulation with less staining and odor compared
with the EC formulation. Prowl H2O does not have to be
incorporated if rainfall is not received within 7 days after application.
At Planting Recommendations:
Rate of Formulated
Material for 1 Acre
Broadcast
Prowl 3.3EC,
Pendimax 3.3EC
2.4 – 3.6 qt
OR
Prowl H2O 3.8CS
2.1 – 3.1 qt
Weeds Controlled
Remarks
Seedling johnsongrass,
itchgrass, browntop panicum,
and other annual summer
grasses
May be applied to soil surface or incorporated. Use higher rate
on heavy soils, if surface applied, planting in July or August, or
if itchgrass is a problem. Other herbicides should be applied
to the soil surface for broadleaf weed control. Addition of
Sencor or DuPont K-4 can enhance control of grass and
broadleaf weeds. Prowl H2O is a capsule suspension (microencapsulated) formulation with less staining and odor
compared with the EC formulation. Prowl H2O does not have
to be incorporated if rainfall is not received within 7 days after
application.