INFLUENCE OF CHEMICAL, CULTURAL AND MECHANICAL PRACTICES ON PARA GRASS (Urochloa mutica) MANAGEMENT. Brent Sellers and Sushila Chaudhari

Transcription

1 1 INFLUENCE OF CHEMICAL, CULTURAL AND MECHANICAL PRACTICES ON PARA GRASS (Urochloa mutica) MANAGEMENT Brent Sellers and Sushila Chaudhari

2 Introduction 2 Native to Africa Introduced as a fodder Swollen nodes Leaf sheath and leaf blade covered with hair Ligules consists of a row of short, stiff hairs Prevalent in wetlands

3 Seed Characteristics 3 Flowering from Sep. to Dec. Produce >10,000 seeds/m 2 Poor seed viability Reproduce by stolon

4 Paragrass A problem 4 Survive in wide range of environmental conditions Short periods of drought Shade Fire Brackish water Water-logged Susceptible to frost

5 Paragrass A problem 5 Category 1 invasive species in central and south Florida (FLEPPC 2009) 53% of 448 water bodies infested (Anonymous 2005) Impede water flow in drainage and irrigation canals Restrict recreational activities and navigation of small craft in shallow waterways

6 Paragrass A problem 6 Highly productive and fast growing Allelopathic 53.5 t/ha/yr in well drained soil to 97.8 t/ha/yr in waterlogged conditions (Binh 1998)

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9 Field Experiment T.M. Goodwin WMA 1 st impoundment Saturated Plot size 24 m 360 m 2 nd impoundment Flooded (40 cm water) Plot size 24 m 360 m

10 10 Field Experiment Cont Herbicides rates 1.12 kg ai/ha Glyphosate 2.24 kg ai/ha Glyphosate 3.36 kg ai/ha Glyphosate 0.84 kg ai/ha Imazapyr 1.68 kg ai/ha Imazapyr Split block design with four replications of each treatment

11 11 December 2008

12 12 Field Experiment Evaluation Visual evaluation 4 WAT (week after treatment) Burning Flooding Visual evaluation 2MAB/F and 8MAB/F

13 Control of Paragrass with Glyphosate and Imazapyr Control 4 WAT * * LSD = 6 % control Saturated Flooded Glyphosate Imazapyr Herbicide rate (kg ai/ha)

14 14 April 2009

15 15 April nd Impoundment after flooding

16 16 April st Impoundment at time of flooding

17 17 Field Experiment Evaluation Visual evaluation 4 WAT Burning Flooding Visual evaluation 2 MAB/F and 8 MAB/F *MAB/F = month after burning/flooding

18 18 Control of Paragrass with Glyphosate and Imazapyr Control 6 MAT (2 MA burn/flood) * LSD = 20 % Control Saturated (Delayed flood) Flooded (Immediate flood) 20 0 UTC Glyphosate Imazapyr Herbicide rate (kg ai/ha)

19 19 Control of Paragrass with Glyphosate and Imazapyr Control 12 MAT (8 MA burn/flood) LSD = NS % control UTC Glyphosate Imazapyr Herbicide rate (kg ai/ha)

20 20 December 2008 Prior to Treatment

21 December 2009 One Year After Treatment 21 Average ducks per hunter 2008 = 0 Average ducks per hunter = 2.86 Average for all T.M. G. WMA = 3.14

22 Preliminary conclusion 22 Burning and flooding has dramatic impact on control Timing of flooding is important Initial water level has no impact on long term paragrass control

23 Greenhouse experiment 1 23 Cut 12 plants Burn 12 plants Submerged Saturated Control

24 24 Effect of water treatments on Paragrass stolon dry weight after burning or cutting a a LSD = 5 Weight (g) b Control Saturated Submerged 5 0 c c c Burned Cut

25 Greenhouse experiment 2 June 2010 and repeated in August 2010 Plant stolons collected from RCREC Ona, FL Incomplete three way Factorial (3 X 3 X 5) with completely randomized design

26 Greenhouse experiment 2 cont.. Total 132 flats 44 flats of each node section 9 segments of each node section

27 Control Saturated Submerged

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29 3, 7, 14, 28 and 42 DAT

30 30 Change in para grass biomass over time under saturated and flooded conditions followed by simulated roller-chopping Dry weight (% of control) Y = 105.2*exp(-0.08*X) R 2 = 0.96 Y = 67.6*exp(-0.11*X) R 2 = 0.90 _ Saturated Flooded Duration of water treatment (days)

31 Seasonal variation of TNC concentration on crown Y = X+0.006X X 3 R 2 = 0.78 July Sept TNC (mg/g) Feb March April June May Aug Oct Nov Dec Jan Calendar Days

32 Conclusions 32 Both years field studies revealed that glyphosate and imazapyr are viable options for paragrass control 1.12 kg ai/ha glyphosate 0.84 kg ai/ha imazapyr Burning followed by immediate or seven days delayed flooding One month delayed flooding needs second herbicide application paragrass can tolerate cutting with and without flooding, and burning without flooding, but cannot survive if flooding occurs after burning

33 Conclusions 33 paragrass may be more susceptible to herbicide application in early summer (early May to June) when carbohydrates begin accumulating in reproductive tissues

34 34 Questions?