United States Department of Agriculture National Marine Fisheries Marketing and Regulatory Services Biological Programs Animal and Assessment for the APHIS Plant Health Inspection Service Rangeland Grasshopper and Mormon Cricket Suppression Program May, 2010 Table of Contents Executive Summary .................................................................................................................. vi I. Introduction and Program Description .................................................................................... 1 A. Introduction ................................................................................................................... 1 B. Project Description—APHIS Rangeland Grasshopper and Mormon Cricket Suppression Program......................................................................................................... 2 1. APHIS Activities—Surveys ...................................................................................... 3 2. APHIS Activities—Technical Assistance .................................................................. 3 3. Cooperator Role....................................................................................................... 5 4. APHIS Activities—Chemical Treatment ................................................................... 5 C. Grasshopper Biology .................................................................................................. 13 1. General Description ............................................................................................... 13 2. Grasshopper Outbreaks ......................................................................................... 14 3. Life History and Ecology of Grasshoppers and Mormon Crickets .......................... 14 4. Damage ................................................................................................................. 15 II. Exposure Analysis for Grasshopper Insecticides—Environmental Fate and Transport Modeling ................................................................................................................................... 16 A. Environmental Fate of Program Insecticides ............................................................... 16 1. Carbaryl ................................................................................................................. 16 2. Diflubenzuron ......................................................................................................... 18 3. Malathion ............................................................................................................... 20 B. Aquatic Residue Estimations for Aerial and Ground Applications of Program Insecticides ...................................................................................................................... 21 B. Aquatic Residue Estimations for Aerial and Ground Applications of Program Insecticides ...................................................................................................................... 21 1. Aerial and Ground Drift Assumptions ..................................................................... 21 2. Observed Residue Values from Program Applications .......................................... 26 3. Drift Simulations ..................................................................................................... 28 3. Drift Simulations ..................................................................................................... 28 4. Runoff Simulations ................................................................................................. 30 III. Response Analysis for Grasshoppper Insecticides ............................................................ 32 A. Carbaryl....................................................................................................................... 33 1. Mode of Toxic Action ............................................................................................. 33 2. Fish ........................................................................................................................ 33 3. Aquatic Plants ........................................................................................................ 35 4. Aquatic Invertebrates ............................................................................................. 35 5. Aquatic Toxicity of Formulations and Metabolites .................................................. 36 B. Diflubenzuron .............................................................................................................. 38 1. Mode of Toxic Action ............................................................................................. 38 2. Fish ........................................................................................................................ 38 3. Aquatic Plants ........................................................................................................ 39 4. Aquatic Invertebrates ............................................................................................. 39 5. Aquatic Toxicity of Formulations and Metabolites .................................................. 40 C. Malathion .................................................................................................................... 42 1. Mode of Toxic Action ............................................................................................. 42 ii 2. Fish ........................................................................................................................ 43 3. Aquatic Plants ........................................................................................................ 44 4. Aquatic Invertebrates ............................................................................................. 45 5. Aquatic Toxicity of Formulations and Metabolites .................................................. 46 IV. Environmental Risk Assessment for Rangeland ................................................................ 49 A. Insecticide Risk Assessment Methodology ................................................................. 49 B. Risk Characterization .................................................................................................. 49 1. Carbaryl ................................................................................................................. 49 2. Diflubenzuron ......................................................................................................... 52 3. Malathion ............................................................................................................... 54 V. Effects Determination for Listed Salmonids ........................................................................ 55 A. Species Descriptions ................................................................................................... 56 1. Chinook Salmon Life History and Description ........................................................ 56 2. Steelhead Life History and Description .................................................................. 59 B. Effects Determination for ESUs and Associated Critical Habitat ................................. 61 C. Uncertainty .................................................................................................................. 65 D. Summary ..................................................................................................................... 67 VI. References ........................................................................................................................ 68 Appendix A-1. Carbaryl acute aquatic fish toxicity values ...................................................... 89 Appendix A-2. Carbaryl acute aquatic invertebrate toxicity values ......................................... 90 Appendix A-3. Carbaryl acute sublethal and chronic aquatic toxicity values .......................... 91 Appendix A-4. Carbaryl toxicity values not used in the aquatic effects analysis ..................... 92 Appendix A-5. Diflubenzuron acute aquatic fish toxicity values .............................................. 93 Appendix A-6. Diflubenzuron acute aquatic invertebrate toxicity values ................................ 93 Appendix A-7. Diflubenzuron acute sublethal and chronic aquatic toxicity values ................. 94 Appendix A-8. Malathion acute fish toxicity values ................................................................. 94 Appendix A-9. Malathion acute aquatic invertebrate toxicity values ....................................... 95 Appendix A-10. Malathion toxicity values not used in the aquatic effects analysis ................. 95 iii Tables Table ES-1. Proposed Application Buffers to Protect Listed Salmonids. vi Table ES-2. Effects Determination for Various Salmonid ESUs. .vii Table 1-1. Characteristics of Insecticides Used by the APHIS Rangeland Grasshopper and Mormon Cricket Suppression Program. 6 Table 1-2. Labeled Rates (fl oz/acre) for Grasshopper and Mormon Cricket Control. 10 Table 1-3. Insecticide Application Buffers from Salmonid Critical Habitat. 13 Table 2-1. AgDisp Aerial Modeling Input Parameters. 23 Table 2-2. AgDrift Ground Modeling Parameters for RAAT ULV Applications. 25 Table 2-3. Estimated Aquatic Environmental Concentrations from the Application of Program Insecticides. 29 Table 3-1. Formulation Aquatic Toxicity Data for Carbaryl. 37 Table 3-2. Naphthol Laboratory Acute and Chronic Aquatic Toxicity Values.