Choosing the Right Aquatic Herbicide

Transcription

1 Choosing the Right Aquatic Herbicide 2012 Aquatic Weed Shortcourse Coral Springs, Florida Jim Petta, Valent 1

2 Objectives Why use aquatic herbicides? What are they? Herbicide classes and Key examples Selecting the right tool Note: I use key brands as examples. There may be alternative brand names and products. 2

3 Flood Control and Water Delivery 3

4 Protection of Wildlife Habitat 4

5 Water Use: Hunting? Fishing? Boating? 5

6 Invasive Species Which Destroy Ecosystem 6

7 Human Life Impacts our Water Resources There are essentially almost no natural areas in the world Humans have impacted waterways wherever they live including Florida long before Europeans arrived (Mexico City, others) Natural means to manage unnatural impacts are limited at best Even bio-control agents are a bit unnatural as introduced 7

8 Why Aquatic Herbicides? Because they work Cost effective Efficient Protect water resource Minimal risk to the user and the environment Large data set on e-fate and non-target impacts 8

9 Pretreatment (cabomba, Highlands County) 9

10 7 DAT 10

11 30 DAT Flumioxazin applied at 200 ppb,

12 Duckweed, pretreatment 12

13 14 DAT Flumioxazin at 200 ppb,

14 What are Aquatic Herbicides? Organic chemicals which are highly effective at low doses in controlling or managing target plant species Very limited in number due to high barrier to entry (environmental, toxicology, not efficacy) Selective tools for aquatic plant managers to protect, maintain, or enhance water resources Are herbicides selective or non-selective? Why or why not? 14

15 Common Myths about Aquatic Herbicides True or False? Aquatic herbicides are toxic to fish Aquatic herbicides are toxic to people.. Aquatic herbicides make our water unsafe to drink. Aquatic herbicides are all the same.. Follow the label! 15

16 The Dose Makes the Poison Product rates are determined after extensive research over many years. Optimal efficacy without unacceptable impacts to nontarget organisms Risk = toxicity x exposure (examples of aspirin, gasoline) 16

17 How Do We Know if they are Safe to Use? All herbicides must be registered by the USEPA and deemed to offer more benefit than the risk involved in their use (risk/benefit; not precautionary principle). No action is without risk; so according to EPA, nothing is safe. Tools have degrees of risk; it is the aquatic plant manager who manages this risk/benefit No product is allowed for use in Florida waters until registered by the State following USEPA registration; again reviewing the data package. 17

18 Toxicology= The dose makes the poison Herbicides are labeled at doses that are effective without unacceptable impacts to non-target plants or animals Rate ranges allow managers flexibility to manage target situations depending on lake/pond conditions Labels are written to the dosage/exposures Go off the label, and all the toxicity data are not relevant The label is written to protect you and the environment and to direct the optimal method of use for the product 18

19 Risk/Benefit or Precautionary Principle? Driving to the Short Course Risk/Benefit Risk: Car wreck Traffic jam CEU s/learnings Meeting was important Donuts and coffee Precautionary Car wreck Traffic jam Meteor strike Atomic war Car jacking Others? Which must be listed. No benefit measurement So why would you drive anywhere? 19

20 Scale and Type of Management Aerial Large Lake Irrigation Mgmt. Airboat Small area FL Spring Injection Trmt 20

21 Many Factors Impact Applications Plant Density & Growth Rate Conditions on the DOT Conditions can change Water quality / temp / epiphytes Water exchange (CET) Trmt. Block & edge/ acre 21

22 Misconceptions with Aquatic Herbicides Aquatic plants take up most of the herbicide Plant uptake = 1 to 5 % of herbicide Herbicides mix rapidly top to bottom Herbicide trapped via thermal gradients Dispersion is a minor factor e.g. All treatments should work the same Wind/Flow move herbicide off-target Herbicides Are Dumped Into the Water 22

23 The Principles Remain the Same Proper Plant Identification Know the Strengths and Weaknesses of the Herbicides Concentration and Exposure Relationships How might Environmental Conditions Impact the Treatment 23

24 Plant Identification Numerous submersed plants Native and Invasive Some sites require management regardless of species Use of water body Proper Identification = Proper Mgmt. 24

25 What Makes Herbicides Work? Active plant growth Good growing conditions Non-stressed from injury, weather, etc. Young, new growth usually most susceptible Direct activity depends on mode of action by class Rotation is important to manage resistance! 25

26 Which Aquatic Herbicide Should I use? Selecting the right tool starts with the objectives of the water body Drinking, irrigation, fishing, skiing, aesthetics, flood control, all? What plants are present and which should be removed and why? Speed and timing..hurricane approaching or do we have 90 days? Cost? But is cost the main driver in aquatics? 26

27 Herbicide Classes HRAC Group Mode of Action Chemical Family Active Ingredient Key Brand(s) B Inhibition of acetolactate synthase ALS (aceto hydroxy acid synthase AHAS) sulfonylureas bensulfuron-methyl imidazolinones imazamox ClearCast imazapyr Habitat triazolopyrimidines penoxsulam Galleon pyrimidinyl (thio) benzoates bispyribac-na Tradewind D Photosystem I electron diversion bypyridiliums diquat Reward E Inhibition of protoporphyrinogen oxidase (PPO) N-phenylphthalimides flumioxazin Clipper F1 triazolinones carfentrazone-ethyl Stingray Bleaching: Inhibition of carotenoid biosynthesis at the phytoene desaturase step (PDS) not classified fluridone Sonar G Inhibition of EPSP synthase glycines glyphosate Rodeo O Action like indole acetic acid (synthetic auxins) phenoxy-carboxylic acids 2,4-D multi. pyridine carboxylic acids triclopyr Renovate Z unknowns dicaroboxylic acids endothal Aquathol 27

28 ClearCast Specifications Active Ingredient: imazamox Herbicide Family (Chemical Class): imidazolinones Mode of Action: acetolactate synthase (ALS) inhibitor Key Points: Slow, systemic Regulatory actitivy Exempt from tolerances Wild taro, Chinese tallow For complete details, refer to the product label and the manufacturer. 28

29 Copper (chelates, CuSO4) Specifications Active Ingredient: copper ion Herbicide Family (Chemical Class): elemental copper Mode of Action: cell membrane disruption Key Points: Primarily algae control but some macrophytes Fast acting Water hardness role (fish toxicity may increase with soft water) For complete details, refer to the product label and the manufacturer. 29

30 Habitat Specifications Active Ingredient: imazapyr Herbicide Family (Chemical Class): imidazolinones Mode of Action: acetolactate synthase (ALS) inhibitor Key Points: No submersed activity Excellent on marginal and floating plants Tough grasses: torpedo and Trop. American WG For complete details, refer to the product label and the manufacturer. 30

31 Galleon Specifications Active Ingredient: penoxsulam Herbicide Family (Chemical Class): triazolopyrimidines Mode of Action: acetolactate synthase (ALS) inhibitor Key Points: Slow systemic (requires long contact time) Excellent on rhydrilla, water hyacinth, others Good selectivity to non-targets No swimming, fishing, drinking restrictions For complete details, refer to the product label and the manufacturer. 31

32 Sonar Specifications Active Ingredient: fluridone Herbicide Family (Chemical Class): not classified Mode of Action: Bleaching by the inhibition of carotenoid biosynthesis at the phytoene desaturase step (PDS) Key Points: Slow, systemic (requires long contact time) Excellent on shydrilla, others Highly selective via dose No restrictions on drinking, swimming, or fishing For complete details, refer to the product label and the manufacturer. 32

33 Rodeo Specifications Active Ingredient: glyphosate Herbicide Family (Chemical Class): glycines Mode of Action: Inhibition of EPSP synthase Key Points: Medium speed systemic Excellent on cattail, floating and marginal plants No submersed activity For complete details, refer to the product label and the manufacturer. 33

34 Reward Specifications Active Ingredient: diquat Herbicide family: Bipyridiliums Mode of Action: Photosystem I electron diversion (cell membrane disruption) Key points: Fast acting contact (not burn; reaction in plant) Controls both floating and submersed plants High binding to clay lattice; turbidity For complete details, refer to the product label and the manufacturer. 34

35 Aquathol Specifications Active Ingredient: endothall Herbicide family: Dicarboxylic acid Mode of Action: Unknown/defined Key points: Moderately fast acting contact Controls many submersed plants Potential microbial degradation For complete details, refer to the product label and the manufacturer. 35

36 2,4-D Specifications Active Ingredient: 2,4-D Herbicide family: phenoxy carboxylic acids Mode of Action: Action like indole acetic acid (synthetic auxins) Key points: Highly selective to control broadleaf plants Systemic, slow-acting Controls submersed, floating, and marginal plants For complete details, refer to the product label and the manufacturer. 36

37 Renovate Specifications Active Ingredient: triclopyr Herbicide family: pyridine carboxylic acids Mode of Action: Action like indole acetic acid (synthetic auxins) Key points: Systemic Selective control of submersed and emergent plants For complete details, refer to the product label and the manufacturer. 37

38 Tradewind Specifications (New in 2011) Active Ingredient: bispyribac Herbicide Family (Chemical Class): pyrimidinyloxybenzoic acid Mode of Action: acetolactate synthase (ALS) inhibitor Key Points: Slow systemic (requires long contact time) Excellent on rhydrilla, water hyacinth, others Highly selective for Southern naiad Good selectivity to non-targets No swimming, fishing, drinking restrictions For complete details, refer to the product label and the manufacturer. 38

39 Clipper Specifications (New in 2011) Active Ingredient: flumioxazin Herbicide family: N-phenylphthalimides Mode of Action: Initiates cell membrane disruption by protoporphyrinogen oxidase (PPO) inhibition Key points: Fast acting contact Controls both floating and submersed plants Short half life related to ph (alkaline hydrolysis) No drinking, swimming, or fishing restrictions For complete details, refer to the product label and the manufacturer. 39

40 Killing Plants is Easy but! Protecting and managing a water resource is not! Selecting the right tool is critical. PLANT ID IS THE NUMBER ONE ISSUE IN PRODUCT PERFORMANCE. All herbicides are NOT the same, even within classes Checkpoints of actions.. 40

41 Environmental Fate - Photolysis fluridone (7-30 d), triclopyr (2-7 d) penoxsulam (7-30 d), imazapyr (4-10 d) - Microbial 2,4-D (4-10 d), endothall (2-7 d), bispyribac-sodium (30-45 d) - Hydrolysis flumioxazin and carfentrazone (hrs to 1 day ph) - Deactivation diquat negatively charged particles (sediments minutes to days) Glyphosate binds to cation ions (Ca,Mg) minutes Copper forms complexes that are not biologically active 41

42 Clipper Environmental Fate Short half life Flumioxazin Aquatic Plant Management ph 5: days Hydrolysis ph 7: hours ph 9: minutes Clipper quickly dissipates from the water column; does not accumulate in soil sediment 42

43 Resistance? Is it Real? Yes! Multiple examples Interesting to note, that generally, as toxicity decreases, resistance potential increases.?!? Why? Single site, multi-site, or unknown Newer products, single site, higher resistance risk! We must manage all products with a long term view! Program Rotation Tank mixes combinations and sequentials! 43

44 Where is the fit for the Right Herbicide? Efficacy Plant ID? Control the target? Water flow? Toxicology No drinking, fishing or swimming restrictions Herbicide Tool Environmental Fate Non-target plants Water use Water quality 44

45 Aquatic Herbicides are.. Critical Tools for aquatic plant management Environmentally compatible to lake management programs Not all alike; make sure the tool fits the need of the site Herbicides are only better than other herbicides due to the site and circumstances! 45

46 Questions? Lake Josephine, FL 46