2012: How Tillage and Application Timing of Reflex Affects Palmer Amaranth Control

J. M. Kichler1, and A. S. Culpepper1

1 University of Georgia Cooperative Extension

Tillage is now a common scene

Growers: Pre-plant*/PRE herbicides appliedPercent (%) of acres treated

37.8

45.8

26.9

15.1

25.1 24.7

2.8

26.9

8.1

81

0

10

20

30

40

50

60

70

80

90

100

2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010

Diuron Fluometuron Pyrithiobac Flumioxazin Fomesafen

Perc

ent (

%) o

f acr

es tr

eate

d

*

*

*

*

Percent control of Palmer amaranth by Reflex as impacted by tillage. 38 DAP.*

0

20

40

60

80

100

80 B91 A

3 C

Prowl 1 pt/A + Reflex 1 pt/A

strip-tillfield cultivator

rototiller

75 B

disk

PPI- shallow incorporation

Prowl (1 pt) + Reflex (1 pt)30 days after treatment

PPI-Disk

Tillage in Cotton During 2010%PPI

tillageGA Counties

#

0 0

1-9 Worth, Pulaski, Tift, Berrien, Echols, Turner, Brooks,

Pierce, Marion, Grady,

10

10-19 Emanual, Montgomery, Atkins, Coffee, Lowndes, Dooly,

Wilcox, Thomas, Crisp, Schley, Webster, Colquitt

11

20-29 Bullock, Jefferson, Treutlen, Wheeler, Daugherty 5

30-50 Effingham, Telfair, Tattnall, Dodge, Toombs, Jeff Davis,

Bleckly, Early, Lanier, Irwin, Lee, Macon

13

>50 Jenkins, Johnson, Washington, Screven, Wayne, Laurens,

Randolf, Decatur, Seminole, Miller, Taylor Ben Hill

12

Percent Palmer Amaranth control with Reflex PPI and PRE in 2010.

99 A

79 B

98 A

Irrigated Dryland

Reflex: Soil moist at planting; rainfall 13 DAT.

PPIPRE

Cotton injury is a big concern for growers!!

Irrigated May 13

Planted May 14

Irrigated May 19 during emergence

None Prowl + Reflex PRE

Prowl + Reflex PPI - Rototill

Objective

To determine if PRE, PPI or PRE and PPI split applications (PPI fb PRE) of Reflex has an impact on Palmer amaranth control.

Materials and Methods

• Tift County• Plot Size 6 by 25 feet• Replicated 4 times• Randomized Complete Block Design• DP 1050 BRF• 10 Treatments

Application Methods

• PPI with a field cultivator before planting

• PRE immediately after planting

• Irrigated (no irrigation or rainfall for 7 DAT)

Herbicide Treatments: Comparison 1

• PPI Options:– Prowl + Reflex 1 pt/A– Prowl + Reflex 1.5 pt/A

• PRE Options:– Prowl + Reflex 1 pt/A– Prowl + Relfex 1.5 pt/A

• Split (PPI fb PRE)– Prowl + Reflex 0.5 pt/A fb Reflex 0.5 pt/A– Prowl + Reflex 0.75 pt/A fb Reflex 0.75 pt/A

Percent cotton injury with Reflex PPI, PRE, or Split Applied at 12 DAT.

2 D

Prowl H2O 2 pts/A included with all treatments.

5 C

15 A

5 C

Percent Palmer Amaranth control with Reflex PPI, PRE, or Split Applied at 35 DAT.

60 D

72 C81 B

Prowl H2O 2 pts/A included with all treatments.

98 A 95 A

Non-treated

Prowl + Reflex 1 pt PPI

Prowl + Reflex 1 pt PRE

Prowl + Reflex ½ pt fb ½ pt Split Application

Herbicide Treatments: Comparison 2

• Split (PPI fb PRE)– Prowl + Reflex 0.75 pt/A fb Reflex 0.5 pt/A– Prowl + Reflex 0.75 pt/A fb Reflex 0.75 pt/A– Prowl + Reflex 1 pt/A fb Reflex 0.5 pt/A– Prowl + Reflex 0.75 pt/A fb Reflex 0.5 pt/A + diuron

Percent cotton injury with Reflex Split Applied at 12 DAT.

0 B

Prowl H2O 2 pts/A included with all treatments.

Percent Palmer control with Reflex Split Applied at 35 DAT.

95 A 96 A 99 A

Prowl H2O 2 pts/A included with all treatments.

Percent Palmer control with Reflex Split Applied at 35 DAT.

95 A 96 A 99 A

Prowl H2O 2 pts/A included with all treatments.

Conclusions

• In irrigated production, PRE applications are more effective if injury is not a concern.

• In dryland production, the split applications give you the best of both worlds.

Any Questions?