Chemical Treatments What types of chemical treatments are there? Why are chemical treatments used? How are chemical treatments applied? What are the effects of chemical treatments?

Chemical Treatments Types of Chemical Treatment –Pesticides Herbicides Insecticides –Fertilizers Credit: florida stateparks.org Credit: uregin.ca

Chemical Treatments Herbicide Use –Last option in wildlife management Manipulate vegetation –Favor desired plant species –Reduce undesirable species Credit: flickr.com

Chemical Treatments Herbicide Use –An alternative for Manipulating plant succession Altering habitat structure Controlling unwanted plants Preventing invasion by woody plants Maintaining openings Top-killing strong sprouters –Often used in conjunction with other methods

Chemical Treatments Herbicide Use –Advantages Can be used in difficult terrain Variety of application methods Provides a rapid control method Has low labor and fuel requirements Selective types available Can maintain grass and litter cover –Does not expose soil –Reduced erosion Can be safe and reliable if done properly

Chemical Treatments Herbicide Use –Disadvantages May not control some noxious species Careless use hazardous Lack of selectivity in some cases Decrease plant diversity Often drastically reduces forbs Can have direct and indirect effects on wildlife and habitat

Chemical Treatments Kinds of Herbicides –Foliar-active Applied directly to leaves and stems –Liquids and soluble powders –Contact (often less selective) –Translocated/systemic (often more selective) »Photosynthetic activity important - Low light and soil moisture, and high temps a problem Credit: forestryimages.org

Chemical Treatments Kinds of Herbicides –Soil-active Applied to soil surface –Liquids or pellets –Sterilant (contact; often less selective) –Translocated/systemic (often more selective) Precipitation important to get to root zone Credit: agweb.com

Chemical Treatments Kinds of Herbicides –Hexazinone (e.g., Velpar): Soil*/Trans Non-selective; some selective for conifers –Imazapyr (e.g., Arsenal): Soil & Foliar/Trans Conifers resistant –Glyphosate (e.g., Round-up): Foliar/Trans Non-selective –Triclopyr (e.g., Garlon): Foliar/Trans Most grasses resistant

Chemical Treatments Kinds of Herbicides –Piclorum (e.g., Tordon): Foliar/Trans Woody plants and broadleaved (forb) weed control –2-4-D (e.g., Relay): Foliar/Trans* Most grasses resistant; kills forbs –Glufosinate (e.g., Liberty): Foliar/Contact Non-selective; kills forbs; some crop resistance –Paraquat: Foliar/Contact Non-selective

Chemical Treatments Herbicide Specificity and Effectiveness –Tuned to targets Grass Broadleaves (herbaceous and woody) –Genus/species Forbs often most severely effected non-target type Credit: fipr.state.fl.usCredit: forestryimages.org

Chemical Treatments Herbicide Specificity and Effectiveness –Stage of plant development –Season –Soil temperature –Precipitation and soil moisture

Chemical Treatments Herbicide Application –Aerial Fixed wing or rotary wing aircraft –Spray –Pellets Rapid application Large areas Remote areas Rough terrain Unselective Credit: mainemark.com

Chemical Treatments Herbicide Application –Ground Tractor-mounted Hand applied –Spray –Pellets Selective targets Small areas Intensive Credit: co.uintah.ut.us

Chemical Treatments Short- and Long-Term Herbicide Effects –Persistence in the environment Herbicide longevity and residue “…that quantity of a herbicide remaining in or on the soil, plant parts, animal tissues, whole organisms, and surfaces”

Chemical Treatments Short- and Long-Term Herbicide Effects –Persistence in the environment Herbicide longevity and residue –Negative connotations –Degree of persistence needed Ideally herbicides persist long enough to have the effect and then dissipate quickly and completely

Chemical Treatments Short- and Long-Term Herbicide Effects –Persistence in the environment Herbicide longevity and residue –Chemical attributes –Concentration applied –Soil characteristics –Climate Generally, increased temperature and soil microflora, organic matter, and moisture accelerates herbicide degradation; leaching effects Soil applied (v. foliar) usually persist longer Case study: Tebuthiuron (soil applied) found 11 years later

Chemical Treatments Short- and Long-Term Herbicide Effects –Direct wildlife impacts Mortality –Generally less toxic than insecticides –Usually do not biomagnify Case studies –Trifluralin »LD50 at normal applications for mallard embryos –Paraquat »High rates of mortality for mallard embryos at ½ recommended application rate

Chemical Treatments Short- and Long-Term Herbicide Effects –Indirect wildlife effects Vegetation Structure and Composition Food and Cover –Increase abundance and diversity »Dominant plant- exotic, invasive »Shrub invasion Credit: smslrwma.org

Chemical Treatments Short- and Long-Term Herbicide Effects –Indirect wildlife effects Vegetation Structure and Composition Food and Cover –Decrease abundance and diversity »Forb Suppression Credit: invasiveplants.ab.ca

Chemical Treatments Herbicide Use –Balance pros and cons Reduced use during the past 50 years Some banned

Chemical Treatments Insecticide Use –Control insect pests Plants Livestock Credit: forestryimages.org

Chemical Treatments Kinds of Insecticides –Chlorinated hydrocarbons DDT, Aldrin, Dieldrin –Organophosphates Malathion, Parathion –Carbamates Fenoxycarb –Pyrethrins

Chemical Treatments Kinds of Insecticides –Attack central nervous system –Highly toxic –Persist in environment Insecticide Application –Aerial –Ground Credit: newswire.com Credit: birdie.com

Chemical Treatments Short- and Long-Term Insecticide Effects –Direct wildlife impacts Mortality –Primary poisoning –Secondary poisoning –Biomagnify Endocrine Disruption –DDT Aquatic Systems Credit: friends of blackwater.org Credit: scienceclarified.org

Chemical Treatments Short- and Long-Term Insecticide Effects –Indirect effects Food –Decrease abundance and diversity »Arthropod losses »Case of upland game birds Credit:eveanderson.com

Chemical Treatments Fertilizer Use –Permit plant establishment –Alter plant composition –Increase nutrients available to plants –Increase palatability of forage –Soil tests required pH important

Chemical Treatments Kinds of Fertilizer –Soil Absorbed through roots –Foliar Absorbed through leaves

Chemical Treatments Kinds of Fertilizer –Combinations of Nitrogen (N), Phosphorus (P)*, and Potassium (K) –Secondary nutrients Calcium, sulfur, magnesium –Micronutrients Boron, chlorine, manganese, iron, … –Organic or Inorganic –Natural or manmade Credit: grow.ars-informatica.ca

Chemical Treatments Fertilizer Application –Aerial –Ground –Season Credit: forestryimages.org Credit: columbiabasinhelicopters.com

Chemical Treatments Fertilizer Effectiveness –Grasses, shrubs, and forbs N –Legumes P N possibly as seedlings Sulfur –Care not to depress legumes Grass:legume ratio in grasslands –N Credit: forestryimages.org

Chemical Treatments Short- and Long-Term Fertilizer Effects –Direct wildlife impacts Mortality –Low –Pellet form = grit

Chemical Treatments Short- and Long-Term Fertilizer Effects –Indirect wildlife impacts Vegetation structure and composition –Food and Cover »Increase quantity and quality »Decrease diversity Aquatic (and some terrestrial) systems and eutrophication (N and P)

Chemical Treatments –Types –Why they are used –How they are applied –Effects