Oxalis stricta (Oxalis)

Early Post-emergent control of Oxalis stricta (Oxalis)

Chris Marble and Charles Gilliam

Materials and Methods:

• 2 experiments conducted to determine postemergence control of oxalis.

• All trials conducted at Paterson Greenhouse Complex – Auburn, AL.

• Oxalis seed were sown at two different dates onto trade gal. pots filled with PB:Sand (6:1) media and standard amendments.

Materials and Methods, Experiment 1:

Growth Stage Pots Filled/Overseeded Treated

2 – 4 Leaf 5/31/2011 6/18/2011

Cotyledon – 1 Leaf 6/7/2011 6/18/2011

Cotyledon to 1 Leaf 2 to 4 Leaf

72˚ at time of treatment

Materials and Methods, Experiment 2:

Growth Stage Pots Filled/Overseeded Treated

2 – 4 Leaf 7/6/2011 7/29/2011

Cotyledon – 1 Leaf 7/18/2011 7/29/2011

Cotyledon to 1 Leaf 2 to 4 Leaf

90˚ at time of treatment

Postemergent stages before treatment

Herbicides Evaluated

Experiment 1 1. Gallery - 0.5 lbs ai/A 2. Gallery – 1.0 lbs ai/A 3. Indaziflam SC - 50 g ai/ha 4. Indaziflam SC – 100 g ai/ha 5. Tower - 21 fl. oz./A 6. Tower – 32 fl. oz./A 7. Non-ionic surfactant – 0.25% 8. Control

Experiment 2 1. Gallery - 0.5 lbs ai/A 2. Gallery – 1.0 lbs ai/A 3. Indaziflam SC - 50 g ai/ha 4. Indaziflam SC – 100 g ai/ha 5. Tower - 21 fl. oz./A 6. Tower – 32 fl. oz./A 7. Control

Materials and Methods:

• Herbicides applied at 20 gpa. • All herbicides applied with CO2

backpack sprayer (25 psi, 80-04 nozzle).

• Foliage dry at time of application – dry for 4 hrs. following application.

• Plants kept under 30% shade. • Daily overhead irrigation (0.5 in).

Data Collected:

• Injury ratings at 1, 2, 4, and 8 weeks after treatment (WAT).

• Fresh weights at 8 WAT.

Experiment 1 Results

Exp. 1 - Cotyledon to 1 Leaf Injury Ratings at 8 WAT

1.8 c

3.5 b

10.0 a 10.0 a

1.7 c

0.0 d 0.0 d 0.0 d 0123456789

10

Injury Ratings (0 – 10)

Exp. 1 - Cotyledon to 1 Leaf Fresh Weights at 8 WAT

18.6 c 5.0 c 0.0 d 0.0 d

36.0 b 50.0 b

98.6 a 91.8 a

020406080

100120

Oxalis Fresh Wt (g)

Cotyledon to 1 Leaf at 8 WAT

Gallery 0.5 lbs aia

Gallery 1.0 lbs aia

Indaziflam 50 g ai/A


Tower 21 fl.oz. aia

Tower 32 fl.oz. aia

Surfactant 0.25% Control

Exp. 1 – 2 to 4 Leaf Injury Ratings at 8 WAT

0.0 b 0.0 b

10.0 a 10.0 a

0.0 b 0.0 b 0.0 b 0.0 b 0123456789

10


Exp. 1 - 2 to 4 Leaf Fresh Weights at 8 WAT

111.3 a

80.1 b

0.0 c 0.0 c

100.3 ab 92.6 ab

108.4 a 113.4 a

020406080

100120

Oxalis Fresh Wt (g)

2 to 4 Leaf Stage at 8 WAT

Gallery 0.5 lbs aia

Gallery 1.0 lbs aia



Tower 21 fl.oz. aia

Tower 32 fl.oz. aia

Surfactant 0.25%

Control

Experiment 2 Results

Cotyledon to 1 Leaf Stage (4 WAT)

Gallery (0.5 lbs aia) vs Control Tower (21 oz/A) vs Control

Tower (32 oz/A) vs Control

Exp. 2 – Cotyledon to 1 Leaf Injury Ratings at 8 WAT

4.0 c

6.9 b

10.0 a 10.0 a

7.6 b 7.4 b

0.0 d 0123456789

10

Gallery 0.5lbs ai/A

Gallery 1.0lbs ai/A

Indaziflam50 g ai/ha


Tower 21 fl.oz./A

Tower 32 fl.oz./A

Control


Exp. 2 - Cotyledon to 1 Leaf Fresh Weights at 8 WAT

1.5 b 0.4 b 0.0 b 0.0 b 0.3 b 0.6 b

18.8 a

02468

101214161820

Gallery 0.5lbs ai/A

Gallery 1.0lbs ai/A



Tower 21 fl.oz./A

Tower 32 fl.oz./A

Control

Oxalis Fresh Wt (g)

Cotyledon to 1 Leaf at 8 WAT

Gallery 0.5 lbs aia

Gallery 1.0 lbs aia

Indaziflam 50 g ai/ha


Tower 21 fl. oz./A

Tower 32 fl. oz./A Control

2 – 4 Leaf Stage (4 WAT)

Gallery (0.5 lbs aia) vs Control Gallery (1.0 lbs aia) vs Control

Tower (21 oz/A) vs Control Tower (32 oz/A) vs Control

Exp. 2 – 2 to 4 Leaf Injury Ratings at 8 WAT

1.1 cd

3.5 b

10.0 a 10.0 a

2.5 bc 2.1 bc

0.0 d 0123456789

10

Gallery 0.5lbs ai/A

Gallery 1.0lbs ai/A



Tower 21 fl.oz./A

Tower 32 fl.oz./A

Control


Exp. 2 - 2 to 4 Leaf Fresh Weights at 8 WAT

12.0 b

3.9 bc 0.0 c 0.0 c

14.1 b 16.9 b

52.2 a

0

10

20

30

40

50

60

Gallery 0.5lbs ai/A

Gallery 1.0lbs ai/A



Tower 21 fl.oz./A

Tower 32 fl.oz./A

Control

Oxalis Fresh Wt (g)

2 – 4 Leaf at 8 WAT

Gallery 0.5 lbs aia

Gallery 1.0 lbs aia



Tower 21 fl. oz./A

Tower 32 fl. oz./A

Control

Summary: Cotyledon to 1 Leaf Experiment 1

• All herbicides provided some control compared to non-treated.

• Gallery had lower F.W. than Tower treatments.

• Indaziflam had highest injury ratings (10.0) and lowest F.W. (0.0) of any treatment.

Experiment 2 • Tower treatments and

Gallery (1.0 lbs aia) had higher injury ratings than Gallery (0.5 lbs aia).

• All F.W. were similar in herbicide treated pots.

• Indaziflam treatments had highest injury ratings (10) and had F.W. of 0.0.

Summary: 2 to 4 Leaf Experiment 1

• Indaziflam had higher injury ratings (10) and lower F.W. (0.0) than any other herbicide.

• All treatments except Indaziflam had injury ratings of 0.0 at 8 WAT.

• Gallery (1.0 lbs aia) only other herbicide to have less F.W. than non-treated.

Experiment 2 • Better control than seen

in Expt. 1. • All treatments had

reduced F.W. when compared to non-treated.

• Indaziflam had highest injury ratings (10.0) and F.W. of 0.0 at 8 WAT.

Conclusions: • Best control when applied at early stages of growth. • Best control achieved with Indaziflam – completely

controlled both postemergent stages. • Gallery and Tower worked best when applied at

cotyledon - 1 leaf stage. • Warmer temperatures in Expt. 2 reduced oxalis

growth – increased herbicide efficacy. – Temperature at time of treatment

• Expt. 1 – 72˚ F • Expt. 2 – 90˚ F

QUESTIONS?

Oxalis stricta (Oxalis)

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