Do graminicides have a future in aquatic invasive grass management in Florida? Stephen Enloe Center for Aquatic and Invasive Plants

Transcription

1 Do graminicides have a future in aquatic invasive grass management in Florida? Stephen Enloe Center for Aquatic and Invasive Plants

2 A few of the troublesome invasive grasses in FL Torpedograss West Indian marsh grass Paragrass Tropical American water grass Limpograss Glyphosate Imazapyr Cogongrass Natalgrass Elephantgrass Burma reed

3 ACCase inhibitors 1 (A) (graminicides) Aryloxyphenoxypropionates FOPS Fluazifop Fusilade Diclopfop Hoelon Quizalofop Assure2 Fenoxaprop Fusion Haloxyfop Verdict cyclohexanediones DIMS Sethoxydim Poast, Vantage, TIGR Clethodim Select, Arrow phenylpyrazolins DENS Pinoxaden Axial

4 How graminicides work Inhibit the ACCase enzyme-this stops production of fatty acids This stops formation and maintenance of cell membranes X X

5 ACCase inhibitors Foliar absorbed Move through phloem to meristems Selective (only control grasses) Immediate growth cessation, but Slow to work (7-14 days to see activity) Chlorosis, reddening, necrosis Can pull out the dead leaf whorl No soil activity

6 ACCase inhibitor Symptoms

7 Natural Tolerance and Resistance to Graminicides Non-grasses are tolerant due to an insensitive ACCase enzyme Some grasses are tolerant through metabolism of the herbicide Some grasses have developed herbicide resistance in different ways Insensitive ACCase enzyme Increased production of ACCase enzyme Increased metabolism of the herbicide

8 ACCase inhibitors work in a different way than other aquatic and upland herbicides

9 Aquatic Labeled Amino Acid Inhibitors Imazapyr Imazamox Bispyribac Penoxsulam Metsulfuron (Arsenal, Chopper, Habitat, Polaris) (Clearcast) (Tradewind) (Galleon) (Escort ) 24C for Lygodium control Glyphosate Accord, Roundup, generics

10 Amino Acid Inhibitors Stop production of certain amino acids (the building blocks of protein) Result is cessation of growth, depletion of the amino acid pool and loss of protein synthesis X X X

11 Amino Acid Inhibitor Symptomology Rapid inhibition of root and shoot growth Vein reddening Leaf chlorosis Terminal bud necrosis Slow, whole plant necrosis (2-4 weeks)

12 CAIP Graminicide Research

13 Initial selectivity and efficacy studies Dr. Michael Netherland Evaluate graminicide activity on invasive grasses and selectivity on native emergent species Herbicides tested in mesocosm studies Sethoxydim Clethodim Fluazifop-p-butyl Glyphosate Imazapyr

14 Treatments Conducted in 900 L Tanks

15 Species tested California bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] Knotted spikerush [Eleocharis interstincta (Vahl) Roem. & Schult.] Gulf Coast spikerush (Eleocharis cellulosa Torr.) Broadleaf cattail (Typha latifolia L.) Pickerelweed (Pontederia cordata L.) Broadleaf arrowhead (Sagittaria latifolia Willd.) Egyptian paspalidium [Paspalidium geminatum (Forssk.) Stapf]. Torpedograss (Panicum repens L.)

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22 Untreated Glyphosate Clethodim

23 Initial Summary Selectivity on key native species Demonstrable activity on torpedograss

24 Progress 2015 Experimental Use Permit (EUP) for sethoxydim (TIGR herbicide) 2016 Experimental Use Permit for Fluazifopp-butyl

25 Lakeside Ranch STA, Okeechobee, FL 0.5 Acre plots, 18 inch water depth Airboat application at 50 GPA Applied August 4-5, 2015

26 Treatments Rodeo at 96 oz/a + NIS Habitat at 32 oz/a+ NIS TIGR at 40 oz/a + MSO TIGR at 5% v/v + MSO

27 % Cover Torpedograss %Cover 8/3/15: 0 DAT NS

28 % Cover Torpedograss % Cover 36 DAT B B AB B A

29 TIGR at 40 oz/a 35 DAT

30 TIGR 5% v/v at 35 DAT

31 Habitat 32 oz/a at 35 DAT

32 Rodeo 96 oz/a at 35 DAT

33 % Cover Torpedograss %Cover 164 DAT 366 DAT NS

34 Study Location: Billy Don Grant (BDG) parcel Bonita Springs, FL

35 Materials and Methods Plot size: 20 by 30 feet Randomized complete block design (4 reps) Treatments applied with a CO 2 pressurized boom sprayer at 20 GPA MSO (32 oz/a) added to each treatment Treatments applied near end of dry season Run 1 app timings: A=4/27, B=5/12, C=5/27 Run 2 app timings: A=5/27, B=6/9, C=6/24

36 Treatment Structure Application Rate (fl oz/a) TRT# AI Product App A App B App C 1 Sethoxydim TIGR Sethoxydim TIGR Sethoxydim TIGR Glyphosate + Imazapyr Rodeo + Habitat Untreated none...

37 April 29, 2016

38 June 24, 2016

39 Water depth inches during wet season Daina Stoutenberg, North Star Construction

40 Data Collection and Analysis Above water: Visual % Control data Whole plot basis 30, 60, 90 DAT, 180 DAT Below ground biomass 90, 180 DAT Aquatic sediment sampler 6 inch diameter 8 inch depth 10 cores per plot ANOVA Fisher s Protected LSD (p=0.05)

41 120 Run x treatment : p< Red bars = Run 1 Blue bars = Run 2 % Control 90 DAT )+O cet L(1)+T Facet L(2) Facet L(2)+O Facet L(2)+T Facet L(3) Facet L(3)+O Facet L(3)+T TRTNAME Facet L(1) Facet L(1)+O Facet L(1)+T Facet L(2) Facet L(2)+O Facet L(2)+T Facet L(3) Facet L(3)+O Rodeo+Habita TIGR1 TIGR2 TIGR3 none TRTNAME Facet L(3)+T Rodeo+Habita TIGR1 RU 1 2 TIGR2 T

42 NOTE: From here forward, the data focus will be on Run 2

43 Bars with the same letter are not significantly different at p=0.05 A 30 DAIT B B B C

44 Bars with the same letter are not significantly different at p=0.05 A A A 60 DAIT B C

45 Bars with the same letter are not significantly different at p=0.05 A A A 90 DAIT B C

46 180 DAIT a a a % Control b 20 0 Rodeo+Habita TIGR1 TIGR2 TIGR3 TRTNAME c none Bars with the same letter are not significantly different at p=0.05

47 180 DAIT a b % Cover c Rodeo+Habita TIGR1 c TIGR2 TIGR3 TRTNAME c none Bars with the same letter are not significantly different at p=0.05

48 Untreated at 90 DAT

49 TIGR (1 app at 40 oz/a) at 90 DAT

50 TIGR (1 app at 40 oz/a) at 90 DAT

51 TIGR (2 apps at 40 oz/a) at 90 DAIT

52 TIGR (2 apps at 40 oz/a) at 90 DAIT

53 TIGR (3 apps at 40 oz/a) at 90 DAIT

54 TIGR (3 apps at 40 oz/a) at 90 DAIT

55 Glyphosate + imazapyr (1 app at oz/a) at 90 DAIT

56 What about rhizome kill?

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59 Bars with the same letter are not significantly different at p=0.05 Root/Rhizome biomass (g/0.13ft3) Rodeo+Habita c ab TIGR1 TIGR2 bc TRT DAT90RDW DAT180RDW abc TIGR3 a none 90 DAT: p= DAT: p=0.049

60 10 subsamples per plot harvested to test rhizome sprouting

61 30 days in water after field harvest % of rhizomes with sprouts a DAT90 % sprouting DAT180 % sprouting a a a 90 DAT: p= DAT: p= Rodeo+Habita b TIGR1 TIGR2 TIGR3 TRT none Bars with the same letter are not significantly different at p=0.05

62 Bars with the same letter are not significantly different at p=0.05 Total new shoots 30 days in water after field harvest c Rodeo+Habita a TIGR1 bc TIGR2 TRT TIGR3 DAT90 DAT180 b none a 90 DAT: p= DAT: p= 0.001

63 Summary Sethoxydim mid-spring sequential timings not as effective as late-spring sequential timings Single applications of sethoxydim resulted in insufficient control Repeated applications much more promising Rhizome impact with sethoxydim is not as pronounced as glyphosate + imazapyr, but there appears to be some negative impact

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66 Next Steps: C-139 annex Airboat and aerial torpedo/paragrass treatments Single and sequential treatments Sethoxydim Fluazifop Glyphosate + imazapyr Treatments initiated in November 2016

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68 Questions to be answered Seasonality of effectiveness Water depth influence on efficacy Tank mix utility with other herbicides Are longer retreatment intervals as good as the 14 day interval?

69 Many thanks to SFWMD, USACE, and FWC for funding this research!

70 Questions?

71 UF DISCLAIMER The use of trade names in this presentation is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.