Post on 30-Dec-2015
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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
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
• 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
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
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