Appendix E Table of Contents Appendix E - Herbicide Descriptions

Appendix E Table of Contents Appendix E - Herbicide Descriptions...... 1 Clopyralid (Active Ingredient)...... 1 Glyphosate (Active Ingredient)...... 1 Hexazinone (Active Ingredient)...... 2 Imazapic (Active Ingredient) ...... 2 Imazapyr (Active Ingredient)...... 3 Metsulfuron Methyl (Active Ingredient) ...... 4 Picloram (Active Ingredient) ...... 4 Sulfometuron methyl (Active Ingredient)...... 4 Triclopyr (Active Ingredient)...... 5

Appendix E - Herbicide Descriptions This appendix has summary descriptions of the nine herbicides considered for use in DFPZ maintenance, or for control of noxious weeds that might invade DFPZs as a consequence of maintenance projects. The herbicide descriptions are organized by active ingredient, and presented in alphabetical order. The information in this appendix comes from various sources, including herbicide labels, product Material Safety Data Sheets (MSDS), and the Syracuse Environmental Research Associates, Inc. (SERA) Risk Assessments (refer to Chapter 4 in each SERA Assessment). Three of these herbicides, picloram, imazapic and metsulfuron methyl, are not currently registered for use in California, but could be registered in the next decade. Without such registration, these three herbicides would not be used. However, they were analyzed in this Final Supplement, so that in case they do become registered they could be used. Listing of trade names is not meant to be an endorsement by the USDA Forest Service of any particular herbicide product, nor is it intended to imply that any particular trade name would be used. This is intended for information only.

Clopyralid (Active Ingredient) Trade name: Transline Target plants: narrow range (in California) such as thistles and knapweed, but can affect composites, legumes, buckwheats. Target area on plant: foliar applied, but also has short term (30-45 days) pre-emergent effects. Formulation and When Applied, Method of Application: Liquid formulation, applied in spring/early summer, during active growing season of targeted vegetation. For this Final Supplement: ground- based application using backpack sprayers. How the active ingredient works: auxin growth regulator. Typical active ingredient application rate: about 1/4 lb per acre. Experience in California forestry: more extensive use on private lands than Forest Service lands; since mid- 1990’s; recent use on Forest Service, relatively minor acreage. Soil/water quality: low potential for movement through soil. Human toxicity: moderate to low acute toxicity, not a carcinogen. An impurity in the technical grade material is toxicologically significant: hexachlorobenzene (probable human carcinogen). Wildlife/fish toxicity: slightly to practically nontoxic to birds; practically nontoxic to fish and aquatic invertebrates; practically nontoxic to bees, earthworms. Most recent SERA risk assessment: 1999

Glyphosate (Active Ingredient) Trade names: Accord, Roundup Pro, Rodeo, Glypro, Aquamaster, Glyphosate VMF. Target plants: broad spectrum, effective against most woody and herbaceous plants. Target area on plant: foliar applied. Formulation and When Applied, Method of Application: liquid formulation, applied to foliage in spring/early summer, during active growing season of targeted vegetation. For this Final Supplement: ground-based application, generally using backpack sprayers, although other methods of application,

HFQLG Final Supplement EIS Page E-1 Appendix E - Herbicide Descriptions such as wick applicators, can be used in sensitive areas. For control of tree-form vegetation, treatment of the cut-stump with a concentrated glyphosate formulation, shortly after falling, is effective on certain species; this method can be used during late spring through summer. How the active ingredient works: aromatic amino acid biosynthesis inhibitor. Typical active ingredient application rates in forests: 1-4 lbs per acre; average rate of application in Region 5 over last five years is 3 lbs/acre. Experience in California forestry: extensive since late 1970’s. Soil/water quality: strongly adsorbed by soil particles and organic matter; does not move once in soil. Based on Region 5 water monitoring, not detected in water when Best Management Practices are implemented. Human toxicity: slightly to practically non-toxic acute toxicity, not a carcinogen. An impurity in certain formulations is toxicologically significant: 1,4-dioxane (probable human carcinogen). Wildlife/fish toxicity: practically non-toxic to mammals, birds, bees, aquatic invertebrates; slightly toxic to fish; formulated products with some surfactants show moderate toxicity to fish and aquatic organisms. Most recent SERA risk assessment: 1996, 2003

Hexazinone (Active Ingredient) Trade names: Velpar ULW, Velpar DF, Pronone 10G. Target plants: broad spectrum, controls many woody and herbaceous species, including grasses. Target area: soil under or adjacent to target plant; a pre-emergent herbicide Formulation and when Applied, Method of Application: two formulations, a pellet form and a liquid form. Both applied in late fall or early spring, depending on precipitation patterns. Liquid formulation can be applied with backpack sprayer as an area-wide treatment, or in a concentrated form in a selective application within the dripline of the target plant. The pelletized formulation is broadcast applied using a pellet applicator, commonly referred to as a “belly grinder” (in ground applications). How the active ingredient works: photosynthetic inhibitor (taken up by roots, then translocates to leaves. Typical active ingredient application rates in forests: 1-3 lbs per acre; average rate of application in Region 5 over last five years is 3 lbs/acre. Experience in California forestry: extensive since late 1970’s. Soil/water quality: water-soluble, mobile in soils and water. Has been detected in streams and shallow groundwater. Human toxicity: slightly to practically non-toxic acute toxicity, not a carcinogen. Wildlife/fish toxicity: slightly to practically nontoxic to fish, aquatic invertebrates, birds, and bees. Most recent SERA risk assessment: 1996

Imazapic (Active Ingredient) Trade name: Plateau. Target plants: annual, perennial grasses, broadleaf weeds, and vines. Tolerant plants include many warm and cool season grasses, most woody plants, numerous composites and legumes. Grass and forb species are variable in susceptibility (many perennial grasses are tolerant). Annual bromes (cheatgrass), medusahead, Johnson grass, whitetop, and leafy spurge are very susceptible.

Page E-2 HFQLG Final Supplement EIS Appendix E - Herbicide Descriptions Target area: foliar applied for annual and perennial weed control; can be applied pre-emergent for control of annuals. Formulation and When Applied, Method of Application: Liquid formulation. For many species, when used as a post-emergent it is applied to foliage in spring/early summer, during beginning of the active growing season of targeted vegetation. Some species may require later applications (leafy spurge, for example is treated late summer or fall). For this Final Supplement: ground-based application using backpack sprayers. How the active ingredient works: branched-chain amino acid biosynthesis inhibitor (AHAS/ALS); plant resistance can develop. Typical active ingredient application rates: 0.2 lb per acre or less. Experience in California forestry: none; not currently registered in California; outside of California, registered for non-crop uses, as well as pasture and rangelands. Soil/water quality: high soil sorption. Rapid breakdown in surface water (photolysis). Human toxicity: practically non-toxic acute toxicity, not a carcinogen. Wildlife/fish toxicity: slightly to practically nontoxic to mammals, birds, fish, aquatic invertebrates, and honeybees. Most recent SERA risk assessment: 2001

Imazapyr (Active Ingredient) Trade names: Arsenal AC, Chopper. Target plants: broad spectrum - annual, perennial grasses, broadleaf weeds and woody plants. Legumes and most conifers are tolerant (of conifers, true fir, lodgepole pine, Douglas fir tolerant, sugar and ponderosa pine less so). Target area: foliar, cut stump, or stem applied; also pre-emergent control of grasses, broadleaf, and some Ceanothus species, particularly on dry sites. Formulation and When Applied, Method of Application: Liquid formulations. For foliar applications, applied using backpack sprayer or similar, wide window of application, depending upon species targeted (spring to fall). For control of tree-form vegetation, several application methods can be used, utilizing concentrated herbicide: cut stump, as described above; and hack and squirt, in which a series of small cuts are made through the bark around the stem and a small amount of herbicide is sprayed into the cut. Both cut stump and hack and squirt have a wide window of application. How the active ingredient works: branched-chain amino acid biosynthesis inhibitor (AHAS/ALS); plant resistance can develop. Typical active ingredient application rates: about 1/4 lb per acre. Experience in California forests: extensive on private lands since mid-1990’s. Soil/water quality: persistence in soil highly variable; potential for water contamination, although soil sorption is high. Rapid breakdown in surface water (photolysis). Human toxicity: practically nontoxic acute toxicity, not a carcinogen. Wildlife/fish toxicity: practically nontoxic to mammals, birds, fish, aquatic invertebrates, and bees. Most recent SERA risk assessment: 1999

HFQLG Final Supplement EIS Page E-3 Appendix E - Herbicide Descriptions Metsulfuron Methyl (Active Ingredient) Trade name: Escort. Target plants: broad spectrum (annual, perennial broadleaf weeds, woody brush, some annual grasses). Used for control of Rubus species and such invasive plants as Klamath weed, pepperweed, Dyer’s woad, and tall whitetop. Target area: foliar applied, but also has some pre-emergent properties. Formulation and When Applied, Method of Application: Liquid formulation, applied to foliage in spring/early summer, during active growing season of targeted vegetation. For this Final Supplement: ground-based application, generally using backpack sprayers. How the active ingredient works: branched-chain amino acid biosynthesis inhibitor (AHAS/ALS); plant resistance can develop. Typical active ingredient application rates: less than 0.1 lb per acre. Experience in California forests: none; not registered in California Soil/water quality: has the potential for water contamination, can move through soil. Human toxicity: practically non-toxic acute toxicity, not a carcinogen. Wildlife/fish toxicity: practically nontoxic to mammals, birds, fish, and bees. Most recent SERA risk assessment: 2000

Picloram (Active Ingredient) Trade name: Tordon 22K (Restricted-Use Pesticide). Target plants: woody plants, annual and perennial broadleaved plants; most grasses are resistant. Target area: foliar applied; rapidly absorbed by roots and leaves; accumulates in new growth; has pre and post emergent effects. Formulation and When Applied, Method of Application: liquid formulation, applied primarily to foliage, with a wide window of application (spring to fall) depending upon target species. For this Final Supplement: ground-based application, generally using backpack sprayers. How the active ingredient works: auxin growth regulator. Typical active ingredient application rates: about 1/2 lb per acre. Experience in California forests: No recent experience; not registered in California. Soil/water quality: moderate to highly persistent in soil; mobile in soil, may pose a risk of groundwater contamination; rapid breakdown in surface water (photolysis). Human toxicity: moderate to low acute toxicity; not a carcinogen. An impurity in the technical grade material is toxicologically significant: hexachlorobenzene (probable human carcinogen). Wildlife/fish toxicity: slightly to practically nontoxic to birds; slightly to moderately toxic to fish and aquatic invertebrates; nontoxic to bees. Most recent SERA risk assessment: 1999

Sulfometuron methyl (Active Ingredient) Trade name: Oust.

Page E-4 HFQLG Final Supplement EIS Appendix E - Herbicide Descriptions Target plants: broad spectrum - annual, perennial grasses, broadleaf plants (although many species of thistle are tolerant). Target area: soil under or near target plant, has pre and post emergent effects. Formulation and When Applied, Method of Application: granular, but mixed with water and applied as a liquid. Pre-emergent applications are applied in early spring prior to target vegetation germination or during very early growth. Post-emergent applications can be applied during spring. Sufficient rainfall is needed to move the herbicide into the rooting zone. How the active ingredient works: branched-chain amino acid biosynthesis inhibitor (AHAS/ALS); plant resistance can develop (sulfonyl urea family of herbicides). Typical active ingredient application rates: about 0.1 lb per acre. Experience in California forests: limited on private lands; potential issues with off-site non-target vegetation damage and possible conifer growth effects. Soil/water quality: somewhat persistent in soil; movement through soil is possible, water contamination is possible, drift with wind erosion of topsoil is possible. Human toxicity: low to slight acute toxicity, not a carcinogen. Wildlife/fish toxicity: slightly to practically nontoxic acute toxicity to mammals, fish, birds, and aquatic invertebrates. Most recent SERA risk assessment: 1998

Triclopyr (Active Ingredient) Trade names: Garlon 4, Garlon 3A, Pathfinder. Target plants: broad leaved plants, woody plants; not effective on grasses. Target area: foliar, cut stump, or stem applied. Formulation and When Applied, Method of Application: liquid formulations. For foliar applications, applied using backpack sprayer or similar, wide window of application, depending upon species targeted (spring to fall). For control of tree-form vegetation, several application methods can be used, utilizing a more concentrated herbicide: cut stump, as described above; hack and squirt, in which a series of small cuts are made through the bark around the stem and a small amount of herbicide is sprayed into the cut; basal bark or thinline, in which an herbicide/oil formulation is applied to the lower portion of the stem. Cut stump, hack and squirt, and basal/thinline have a wide window of application. How the active ingredient works: auxin growth regulator. Typical active ingredient application rates: 1-2 lbs per acre; average rate of application in Region 5 over last five years is 1 lb/acre. Experience in California forests: extensive since late 1970’s. Soil/water quality: does not easily move through soil. Based on Region 5 water monitoring, not detected in water when Best Management Practices are implemented. Human toxicity: low acute toxicity, not a carcinogen. Inert ingredients are toxicologically significant (kerosene in Garlon 4, ethanol in Garlon 3A). Wildlife/fish toxicity: Slightly toxic to mammals, birds, fish; slightly toxic to practically nontoxic to bees, and soil and aquatic invertebrates. Most recent SERA risk assessment: 1996, 2003

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