Weed Management for “Newer” Peanut Counties

Dr. Eric P. Prostko

Extension Weed Specialist

Dept. of Crop & Soil Sciences

University of Georgia

TiftonApril 2004

Some things to think about….

know your weeds rotational crops field by field

treatments?? weed competition

Weed Competition

100% weed control is not practical 1st 4-6 weeks most important later emerging weeds usually do not

cause yield losses (harvest problems) all weeds are not created equal generally, grass weeds more competitive

than broadleaf weeds

Peanut yield losses (%) caused by various weeds

at a density of 1 plant/meter of crop row.

70

40

3124

2014

0

15

30

45

60

75

Source: Thomas et al., 2004, Weed Technology 18:119-123

The Peanut Weed Control Toolbox16 active ingredients

PPI/PRESonalanProwl/PendimaxDual MagnumFrontier/OutlookPursuitStrongarmValorZorial

POSTGramoxone MaxBasagranUltra BlazerCadreClassicPoastPursuitSelect/ArrowStorm

2,4-DB

The foundation of weed management in peanuts is the yellow/DNA herbicides!

Sonalan, Prowl, Pendimax , Prowl H2O

inexpensive Texas panicum Florida pusley must be incorporated

by tillage or irrigation

Herbicide Incorporation

type of equipment number of passes soil condition

– too wet• reduce soil movement

• clods

• increase in volatility

– too dry• reduced adsorption

• increased soil flow

Herbicide Incorporation

Herbicide Incorporation

or

Equally as effectiveCenter-pivot irrigation is $2-7/A cheaper!

Strongarm or Valor

soil-applied broadleaf weed both weak on

sicklepod crop injury rotation restrictions price/A

Strongarm vs. Valor

Strongarm ValorFL beggarweed + ++y. nutsedge + -b. starbur ++ +t. croton + ++morningglories ++ +poinsettia + +RotationsInjury problemsCost/A

-no

16.00

+yes

13.50

Avoid Valor Injury

read entire label!! calibrate sprayer plant at least 1.5” deep apply immediately after

planting rainfall at-cracking will

cause injury clean sprayer before

treating cotton

Valor Clean-Up Procedures

tank vs. hose issue polyurethane vs.

rubber anti-drip systems with

diaphragms flush hoses after use release pressure delay spraying for 20-

30 seconds

Valor Rotation Restrictions

Strongarm Rotational Restrictions

Consider Using Paraquat

less than $2.00/A if not using Valor or

Strongarm if beggarweed, sicklepod

and t. panicum are main problems

apply early tank-mixes with Basagran,

Storm, 2,4-D, Dual

Gramoxone Max 8 ozs/A

Gramoxone Max10 ozs/A

+ Storm (1.5 pt/A)

1 DAT

Consider Using Cadre controls most weeds

except ragweed, croton, bristly starbur

Is it worth the rotational crop risk??

Cadre Rotational Restrictions

When is the best time to use Cadre?

following an “at-crack” application of paraquat

or following a PRE

application of Valor or Strongarm

If you cannot use Cadre…...

weed control costs will probably be higher purple nutsedge will not be controlled Dual Magnum ($10-14/A) but not as

effective. Older herbicides (Basagran, Blazer, Storm)

effective but have some weaknesses

Enemies of POST Herbicides

dry weather big weeds

Get the most from your Posts!

can’t do much about the weather but can greatly influence application * calibration

* timing

* adjuvants

* nozzle selection

* spray volume

* antagonism

Optimum Timing of POST Applications

definitely

probably

No way!!!

Weed control programs for $355/ton peanuts?(approximate costs/A)

Program 1(15 GAP, not including application)

Herbicide Rate/A Timing Cost/A

Sonalan 2 pts PRE 5.66

Valor 3 ozs PRE 13.50

Cadre 1.0 ozs POST 12.00

Crop Oil 1% v/v POST 1.62

Total 32.78

Program 2 (15 GAP, not including application)

Herbicide Rate/A Timing Cost/A

Pendimax 2.4 pts PRE 5.10

Strongarm 0.45 ozs PRE 16.00

Cadre 1.00 ozs POST 12.00

Crop Oil 1% v/v POST 1.62

Total 34.72

* weed resistance potential increased with this program

Program 3 (15 GAP, not including application)

Herbicide Rate/A Timing Cost/ASonalan 2 pts PPI/PRE 5.66

GramoxoneMax

5.5 ozs CRACK 1.59

NIS 0.25% v/v CRACK 0.67Cadre 1.00 ozs POST 12.00

Crop Oil

Total

1% v/v POST 1.62

21.54

Program 4 (15 GAP, not including application)

Herbicide Rate/A Timing Cost/ASonalan 2 pts PPI/PRE 5.66

Gramoxone 5.5 ozs CRACK 1.59Storm 1.5 pt CRACK 12.75NIS 0.25%

v/vCRACK 0.67

Cadre 1.00 ozs POST 12.00Crop Oil

Total

1% v/v POST 1.62

34.29

What herbicides do the top “older” peanut growers use?

2003 Peanut Achievement Club 16 Farms

– average farm size• 454 acres

– average yield• 5141 lbs/A

Top 5 herbicides used– Sonalan = 94%– Cadre = 81%– Gramoxone Max = 56%– 2,4-DB = 50%– Valor, Basagran = 37%