S.G. Wilson, A.S. Culpepper, and A.C. York University of Georgia and N. C. State University

S.G. Wilson, A.S. Culpepper, and A.C. York

University of Georgia and N. C. State University

MANAGING LARGE MORNINGGLORY IN ROUNDUP – READY COTTON

WITH LAY-BY HERBICIDES

STUDY OBJECTIVE:

To Evaluate Lay-By Herbicide Options For Controlling Large Pitted Morningglories

And Evaluate Plant Injury

Locations

Moultrie*Ocilla*

Materials & Methods

• RR Variety Sprayed at 4-Leaf Stage w/ Commercial Broadcast Sprayer

• Plots Sprayed At Lay-By w/ Backpack Sprayer @19psi & 14.8 GPA

PITTED MORNINGGLORY

Materials & Methods

• Randomized Complete Block Design

• Four Replications

Materials & Methods

• Treatments Evaluated At ~ Two And Four Weeks For Efficacy

• Treatments Evaluated At ~ One And Two Weeks For Injury

Treatments:

• RU + Aim• RU + MSMA• Caparol + MSMA• Direx + MSMA• Valor + MSMA

• RU• RU + Direx• RU + Harvade + COC• RU + Staple• RU + Valor

*RU abbreviated for various brands of Monsanto’s glyphosate products at 1 lb ai/A, Staple 0.6 to 0.8/A oz, Direx 1.0-1.5 pt/A when mixed with RUand 2 pt/A when mixed with MSMA, Harvade 6-8 oz/A, Aim 0.8-1 oz/A, MSMA 2 lb ai/A Valor 1 oz/A when mixed with RU and 2 oz/A when mixed with MSMA,

Caparol 2 pt/A, and COC 1 pt/A.

Morningglory Response to Lay-By Herbicides. 2001.

TREATMENTS

3-4 ft mg*

15 DAT 35 DAT

RU 50 c 55 c

RU + Direx 35 d 55 c

RU + Harvade + COC 53 c 63 bc

RU + Staple 36 d 63 bc

RU + Valor 80 a 74 ab

RU + Aim 65 b 58 c

RU + MSMA - -

Caporal + MSMA 55 bc 59 c

Direx + MSMA 55 bc 59 c

Valor + MSMA 81 a 83 a* Values followed by the same letter within a column are not different at P=0.05

No Directed Application

No Directed Application

Roundup UltraMax 1.6 pt

No Directed Application

Roundup UltraMax 1.6 pt + Valor 1 oz

No Directed Application

Valor 2 oz + MSMA 2 lb

No Directed Application

Roundup UltraMax 1.6 pt + Harvade 6 oz

No Directed Application

Morningglory Re-growth

• Treatments including Aim looked excellent initially, but MG’s suckered back out by 14 DAT (right)

Morningglory Response to Lay-By Herbicides. 2002.

TREATMENTS

2 ft mg*

16 DAT 36 DAT

RU 59 e 67 f

RU + Direx 47 g 74 c-f

RU + Harvade + COC 78 bcd 76 def

RU + Staple 95 a 86 a-d

RU + Valor 92 a 91 ab

RU + Aim 94 a 84 a-e

RU + MSMA 80 bc 89 abc

Caporal + MSMA 68 de 81 bc

Direx + MSMA 72 cd 79 c-e

Valor + MSMA 88 ab 95 a* Values followed by the same letter within a column are not different at P=0.05

Large Pitted Morningglory Response to Lay-By Herbicides. 2003.

TREATMENTS

9 in mg*

15 DAT 39 DAT

RU 76 c 74 c

RU + Direx 97 a 92 ab

RU + Harvade + COC 91 ab 87 abc

RU + Staple 87 bc 84 bc

RU + Valor 96 ab 94 a

RU + Aim 99 a 92 ab

RU + MSMA 92 ab 92 ab

Caporal + MSMA 91 ab 81 cd

Direx + MSMA 97 ab 84 bc

Valor + MSMA - -* Values followed by the same letter within a column are not different at P=0.05

Cotton Response to Lay-By Herbicides*

‘01 (14” cotton, green)

‘02 (23” cotton, bark)

‘03 (15” cotton, bark)

5 DAT 14 DAT 5 DAT 16 DAT 7 DAT 16 DAT

RU 0 d 0 d 0 d 3 d 2 c 2 d

RU + Direx 0 d 0 d 6 bc 9 a 7 b 2 d

RU + Harvade + COC 9 c 6 c 6 bc 4 d 10 ab 12 a

RU + Staple 0 d 0 d 0 d 3 d 0 d 1 d

RU + Valor 16 b 12 b 3 cd 3 d 12 a 2 d

RU + Aim 25 a 18 a 15 a 5 cd 12 a 3 cd

RU + MSMA - - 3 cd 4 d 10 ab 8 b

Caporal + MSMA 0 d 2 d 1 cd 6 abc 9 ab 3 cd

Direx + MSMA 3 d 3 d 9 b 8 ab 8 b 6 bc

Valor + MSMA 18 b 13 ab 8 b 4 d - -

* Values followed by the same letter within a column are not different at P=0.05

Non-treated Control

Soil Uptake of Harvade

Herbicide Injury

• Cotton was extremely green (no woody material) at time of application

• At 5 DAT, injury ranged from 16-25% for Aim or Valor Mixtures

Summary

• On 3-4’Mg, RU + Valor or Valor + MSMA were the most effective treatments

• On 2’ MG, RU + Staple, Valor, or Aim as well as Valor + MSMA were the most effective treatments

• On 9” Mg, the most effective treatments were Direx, Harvade, Valor, Aim or MSMA when mixed with RU

Summary

• Tank mixes including Aim and Valor were more injurious

• Injury was worse on green cotton

• Harvade injury appeared as leaf chlorosis

• Injury was short-lived

Summary

• No differences in yield were noted

• Early season weed competition was similar across the trial

QUESTIONS?

THE END