Do graminicides have a place in aquatic invasive grass control? Stephen F. Enloe

Transcription

1 Do graminicides have a place in aquatic invasive grass control? Stephen F. Enloe

2 Troublesome invasive grasses in FL Torpedograss Cogongrass West Indian marsh grass Paragrass Tropical American water grass Natalgrass Elephantgrass Burma reed Limpograss Glyphosate Imazapyr

3 Recovery from rhizomes and stolons often thwarts long term control Karen Brown, CAIP, Bugwood.org

4 What about Graminicides? FOPS Fluazifop Fusilade Diclopfop Hoelon Quizalofop Assure2 Fenoxaprop Fusion Haloxyfop Verdict DIMS Sethoxydim Poast, Vantage, TIGR Clethodim Select, Arrow

5 They may not be great on large perennial invasive grasses However are they good enough, given the benefit of selectivity?

6 TIGR Herbicide (2015 Experimental Use Permit- FL15-EUP-01) FOR EXPERIMENTAL USE ONLY For use only at an application site of a cooperator and in accordance with the terms and conditions of the Experimental Use Permit. Not for use by any person other than a participant or cooperator of the Florida-approved Experimental Use Program FOR DISTRIBUTION AND USE ONLY WITHIN FLORIDA UNDER EUP No. FL15-EUP-01 TIGR HERBICIDE For evaluation as a foliar-applied herbicide for the selective control of invasive grasses such as torpedograss, West Indian marsh grass, para grass, and Tropical American water grass, in ponds, lakes, swamps, riparian areas, wetlands, marshes, reservoirs, and other areas adjacent to aquatic sites. Active Ingredient: sethoxydim: 2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2- cyclohexen-1-one* % Other Ingredients % TOTAL % *Equivalent to 1.5 pounds of sethoxydim per gallon formulated as an emulsifiable concentrate. Contains petroleum distillate

7 Objective Evaluate the field efficacy of sethoxydim for torpedograss control at broadcast and spot treatment rates

8 Study Location 1: Okeechobee, FL

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

10 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

11 Data Collection and Analyses Torpedograss Cover Five (1 m 2 ) quadrats randomly placed along one transect in each plot 0, 35, 75, 125, and 365 DAT ANOVA using a split plot mixed model to account for repeated measures Tukey s HSD

12 % Cover Torpedograss %Cover 8/3/15: 0 DAT NS

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

14 TIGR at 40 oz/a 35 DAT

15 TIGR 5% v/v at 35 DAT

16 Habitat 32 oz/a at 35 DAT

17 Rodeo 96 oz/a at 35 DAT

18 % Cover Torpedograss %Cover 80 DAT NS

19 60 50 Torpedograss %Cover 164 DAT 366 DAT NS % Cover

20 Study Location: Bonita Springs, FL

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22 Active Ingredient Product Treatments Product Rate/A Application Timing(s) Sethoxydim TIGR 40 oz/a May 27 Sethoxydim TIGR 40 oz/a May 27, June 11 Sethoxydim TIGR 40 oz/a May 27, June 11, June 24 Glyphosate + Imazapyr Rodeo + Habitat oz/a May 27 Untreated All treatments contained methylated seed oil equivalent to 1qt/A

23 Materials and Methods Plot size: 20 by 30 feet Randomized complete block design 4 replicate plots per treatment

24 Application Methods Treatments applied in the dry season Treatments applied with a CO 2 pressurized boom sprayer at 20 GPA

25 Daina Stoutenberg, North Star Construction

26 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 12 inch depth 10 cores per plot = 1.9 ft 2 ANOVA Fisher s Protected LSD (p=0.05)

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29 A 30 DAIT B B B C

30 A A A 60 DAIT B C

31 A A A 90 DAIT B C

32 Untreated at 90 DAT

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

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

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

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

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

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

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

40 What about rhizome kill?

41 90 DAIT

42 10 subsamples per plot harvested to test rhizome sprouting

43 Summary Single applications of sethoxydim resulted in insufficient control Repeated applications appear much more promising Rhizome impact uncertain at 90 DAIT, but does not appear to be as effective as glyphosate+imazapyr

44 Questions?

45 % Cover