Cotton and Palmer Amaranth (AMAPA) Response to

Milo-Pro Applied at-Plant and POST

Lynn M. Sosnoskie and A. Stanley CulpepperUGA, Tifton, GA

Jared WhitakerUGA, Statesboro, GA

Jeremy M. KichlerUGA, Oglethorpe, GA

Alan C. York NCSU, Raleigh, NC

AMAPA is large, competitive, C4 annual that can form dense populations in infested fields,

reducing yields and harvest efficiency

Cotton is particularly susceptible to weed interference

• Planted at lower densities than other crops

• Requires higher temperatures for rapid growth

• Uncompetitive crop canopy

1X Weathermax + 1X Staple LX at 5 WAT

1/2 inch in 12 hr

4 inches 52 hr

Residual Herbicide use is needed for the management of AMAPA in cotton

• Milo-Pro TM

– Propazine

– PSII electron transport inhibitor

– PRE and POST for grain sorghum

– 0.75 to 1.2 qts/A for sandy loam to clay loam soils

– Not recommended for sands or loamy sands

– Cotton does have some tolerance to propazine

• Abernathy et al. 1969. Agron. J.

• Kendig et al. 2006. PHP

LocationsMacon County, GA and Moultrie, GA

• Sutton’s Field and Southern Ag Expo• Sandy loam• Planted 28 May, 2009 (Macon)• Planted 14 May, 2009 (Moultrie)• 6’ x 25’ plots, 36” row spacing• DP 0949 B2RF• Herbicide treatments replicated 3X in RCBD• Herbicides applied at application volume of 14.8 Gal/A with

CO2 backpack sprayer and flat fan nozzles

• Crop injury • GLY-R AMAPA control at Macon County site

Macon County and Moultrie, GATRT PRE POST1 POST2

    (2-3 Leaf) (6-8 Leaf)

1 none none none

2Milo-Pro

1 pt/AWMAX WMAX

3Milo-Pro

2 pt/AWMAX WMAX

4Cotoran

2 pt/AWMAX WMAX

5 none WMAX WMAX

6 noneMilo-Pro 1 pt/A

WMAXWMAX

7 noneMilo-Pro 2 pt/A

WMAXWMAX

8 noneParrlay 1.3 pt/A

WMAXWMAX

9 noneStaple 2.5 oz/A

WMAXWMAX

10Reflex 1 pt/A

WMAX WMAX

11Reflex 1 pt/A

Milo-Pro 2 pt/A WMAX

WMAX

12Reflex 1 pt/A

Milo-Pro 1 pt/A WMAX

Milo-Pro 1 pt/A WMAX

Locations

Rocky Mount, NC (2 sites)• Upper Coastal Plain Research Station • Sandy loam• Planted 6 and 13 May, 2009• 12’ x 30’ plots, 36” row spacing • DP 0924 B2RF• Herbicide treatments replicated 4X in RCBD• Herbicides applied at application volume of 14.8 Gal/A with

CO2 backpack sprayer and flat fan nozzles

• Crop injury

Rocky Mount, NCTRT PRE POST1 POST2

    (2-3 Leaf) (6-8 Leaf)

1 none none none

2Milo-Pro

1 pt/APMAX PMAX

3Milo-Pro

2 pt/APMAX PMAX

4Cotoran2 pt/A

PMAX PMAX

5 none PMAX PMAX

6 noneMilo-Pro 1 pt/A

PMAXPMAX

7 noneMilo-Pro 2 pt/A

PMAXPMAX

8 noneParrlay 1.3 pt/A

PMAXPMAX

9 noneStaple 2.5 oz/A

PMAXPMAX

Cotton Injury

Cotton Injury - At Plant Application Data averaged across Macon County and Moultrie, GA, sites

1 WA-PRE 3 WA-PRE

No Pre 0% 0%

Milo-Pro

1 or 2 pt/A

0% 0%

Cotoran

2 pt/A

0% 0%

Reflex

1 pt/A

11% 5%

Reflex Injury at 1pt/A PRE

Cotton Injury – POST Application to 2-3 Leaf Cotton Data averaged across Macon County and Moultrie, GA, sites

1 WA-POST1 3 WA-POST1

Weathermax

22 oz/A

0% 0%

Milo-Pro + Weathermax

1 pt/A + 22 oz/A

0% 0%

Milo-Pro + Weathermax

2 pt/A + 22 oz/A

3% 0%

Parrlay + Weathermax

1.33 pt/A + 22 oz/A

5% 0%

Staple + Weathermax

2.5 oz/A + 22 oz/A

10% 0%

Milo-Pro 2 pt/A plus Roundup POST

1 WA-POST1

Application to 2-3 leaf cotton

Rocky Mount, NC

Some Milo-Pro PRE injury, especially at higher rate, but no more than 10% in any one plot; mean injury was not >6% and was transient

Rocky Mount, NC

Some Milo-Pro POST injury, especially at higher rate, but no more than 10% in any one plot; mean injury was not >8% and was transient

GLY-R AMAPA Control

GLY-R AMAPA Control - At Plant ApplicationMacon County, GA

1 WA-PRE 3 WA-PRE

No Pre 0% 0%

Milo-Pro

1 or 2 pt/A

99% 85-96%

Cotoran

2 pt/A

98% 82%

Reflex

1 pt/A

99% 99%

0

20

40

60

80

100

120

8 22 28 40 47 54 61 80 135

DA-PRE

GL

Y-R

AM

AP

A C

on

tro

l (%

)Milo-pro 1 pt/A Milo-pro 2 pt/A Cotoran 2 pt/A Reflex 1 pt/A

GLY-R AMAPA Control – POST1 ApplicationMacon County, GA

1 WA-POST1 3 WA-POST1

No PRE

Parrlay POST1

0% 0%

No PREMilo-Pro (1 pt) POST1

0% 7%

No PREMilo-Pro (2 pt) POST1

60% 47%

No PRE

Staple POST1

95% 77%

All treatments received Weathermax at 22 oz/A at POST1

0

20

40

60

80

100

6 18 25 32 39 58 113

DA-POST1

GL

Y-R

AM

AP

A C

on

tro

l (%

)

Milo-pro 1 pt/A Milo-pro 2 pt/A Parrlay 1.33 pt/A Staple 2.5 oz/A

GLY-R AMAPA Control – All POST ApplicationsMacon County, GA

1 WA-POST2 2 WA-POST2 1 WA-POST3 3 WA-POST3

Reflex

PRE84% 75% 77% 67%

Reflex

PRE

Milo-Pro (1 pt/A)

POST1

Milo-Pro (1 pt/A)

POST2

97% 94% 93% 93%

Reflex

PRE

Milo-Pro (2 pt/A)

POST1

97% 85% 88% 88%

All treatments received Weathermax at 22 oz/A at POST1 and POST2

All treatments received Direx and MSMA at Layby (POST3)

Reflex PRE fb WMAX fb WMAX fb Direx + MSMA

Reflex PRE fb Milo-Pro (2 pt/A) + WMAX fb WMAX fb Direx + MSMA

Reflex PRE fb Milo-Pro (1 pt/A) + WMAX fb

Milo-Pro (1 pt/A) + WMAX fb Direx + MSMA

GLY-R AMAPA Control and YieldMacon County, GA

End of season control

Yield

(lbs seed cotton/A)

Reflex

PRE

50% 732

Reflex

PRE

Milo-Pro (1 pt/A)

POST1,2

86% 1359

Reflex

PRE

Milo-Pro (2 pt/A)

POST1

78% 1192

All treatments received Weathermax at 22 oz/A POST1 and POST2

All treatments received Direx and MSMA at Layby (POST3)

Cotton Injury and Yield Clayton, NC

% Chlorosis

3 WA-PRE

% GR

3 WA-PRE

Yield(lbs seed cotton/A)

No Pre 0% 0% 2971

Milo-Pro PRE

2 pt/A

10% 13% 2577

Milo-Pro PRE

4 pt/A

27% 32% 2003

Injury ratings of 5 to 7% were observed 1-3 WA-PRE applications of Milo-Pro at 1 pt/A at Attapulgus, GA. No injury was observed 6 WA-PRE. This isn’t different than what was seen at Rocky Mount.

Injury ratings of 13 to 32% were observed 1-3 WA-PRE applications of Milo-Pro at 2 pt/A at Attapulgus, GA. Injury was still 33% 3 WA-POST2.

Previous Research

• Abernathy et al. 1969. Agron. J.

– 48 cotton varieties evaluated for resistance to propazine broadcast PRE at 0.56 kg/ha

– Sandy loam with OM <1%

– Injury ratings ranged from 3-53%• Aubun M, Acala B-3080, Paymaster 303 = 3%• Coker 5110, Coker 312 = 8%• Paymaster 111A, Deltapine SR-2 = 50%• Blightmaster A-5 = 53%

– Less than 20% was regarded as a tolerant response to propazine

Previous Research

• Kendig et al. 2006. Plant Health Progress

– DP 5415RR was screened for tolerant to propazine

– 5 rates: 0, 0.25X, 0.5X, 1X, 2X of 1.12 kg/ha

– 4 growth stages: PRE, cotyledon, 2-lf, 4-lf

– Some injury observed for PRE applications (sandy-loam) but visual injury and weight reductions were greatest from over the top applications made at the cotyledon and 2-lf stages

– Injury increased with rate

Summary

• Milo-Pro applied PRE at 1-2 pts/A injured cotton 0-7% (Attapulgus, Rocky Mount); injury was transient

• There was no observable injury at Macon County and Moultrie for Milo-Pro applied PRE

• Higher rates (4 lbs/A), on sandier soils (Attapulgus, Clayton) with adequate rainfall resulted in unacceptable injury ratings due to PRE applications

• Injury resulting from POST applications of Milo-Pro did not exceed 8%; injury was not greater than what was observed for Staple; injury was transient

Summary• Residual herbicides (PRE and POST) are crucial for managing

Palmer amaranth

• Milo-Pro (2 pt/A) and Reflex (1 pt/A) provided 96% and 99% control, respectively at 3 WA-PRE, the timing of the first POST application

• Milo-Pro was most effective as a POST applied herbicide when following Reflex PRE (residual and topical activity)

• A single application (2 pt/A POST1) or two applications (1 pt/A POST1 and POST2) of Milo-Pro provided 85% and 94% control, respectively, of GLY-R Palmer 2 WA-POST2 and carried the crop to layby and harvest

• According to these results, Milo-Pro may be a useful component in an INTEGRATED program to manage GLY-R Palmer amaranth