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