REPORT FOR THE MINISTRY OF HEALTH Environmental and health impacts of the insect juvenile hormone analogue, S-methoprene Travis R. Glare and Maureen O'Callaghan Biocontrol and Biodiversity, Grasslands Division, AgResearch PO Box 60, Lincoln March, 1999 Contents Abbreviations............................................................................................................................ 4 1. Summary.............................................................................................................................. 5 2. Introduction ......................................................................................................................... 7 2.1. Background..................................................................................................................... 7 2.2. Insect growth regulators ................................................................................................. 8 2.3. Methoprene..................................................................................................................... 8 3. Methoprene-based products............................................................................................. 10 3.1. Application rates........................................................................................................... 12 4. Activity of methoprene ..................................................................................................... 13 4.1. Mode of action and effect of methoprene treatment .................................................... 13 4.2. Sublethal effects ........................................................................................................... 14 4.2.1. Sublethal effects in mosquitoes............................................................................. 14 4.2.2. Effect on morphology/development...................................................................... 14 4.2.3. Effect on behaviour ............................................................................................... 15 4.2.4. Effect on pheromones............................................................................................ 15 4.2.5. Effect on reproduction and sex ratios..................................................................... 15 4.3. Developmental stage affected....................................................................................... 16 4.3.1. Ovicidal activity.................................................................................................... 16 4.3.2. Larvicidal and pupicidal activity........................................................................... 17 4.3.3. Adults .................................................................................................................... 18 5. Susceptible insect and mite species.................................................................................. 19 5.1. Records of susceptible insects and mites ..................................................................... 19 5.2. Comparative toxicity in the laboratory......................................................................... 28 6. Use of methoprene in the field.......................................................................................... 31 6.1 Use of methoprene against insects ................................................................................ 31 6.2. Use for mosquito control.............................................................................................. 32 6.1.1. Aedes spp............................................................................................................... 32 6.1.2. Culex spp............................................................................................................... 33 6.1.3. Mansonia spp. ....................................................................................................... 35 6.1.4. Psorophora spp. .................................................................................................... 35 7. Comparison of efficacy of methoprene with other agents............................................. 37 7.1. Mosquitoes ................................................................................................................... 37 7.1.1. Laboratory............................................................................................................. 37 7.1.2. Field....................................................................................................................... 38 7.2. Flies .............................................................................................................................. 40 7.3. Chironomids ................................................................................................................. 40 7.4. Fleas.............................................................................................................................. 41 7.5. Lepidoptera................................................................................................................... 41 7.6. Chrysomelids................................................................................................................ 41 7.7. Mites............................................................................................................................. 41 8. Use of methoprene in eradication campaigns................................................................. 42 9. Effects on non-target organisms ...................................................................................... 43 9.1. Phytotoxicity ................................................................................................................ 43 9.2. Microorganisms............................................................................................................ 43 9.2.1. Bacillus thuringiensis............................................................................................ 43 Environmental and health impacts of juvenile hormone analogue, methoprene page 2 9.2.2. Protozoa................................................................................................................. 44 9.2.3. Fungi ..................................................................................................................... 45 9.2.4. Virus...................................................................................................................... 45 9.3. Invertebrates ................................................................................................................. 46 9.3.1. Benthic and aquatic communities ......................................................................... 46 9.3.2. Nematoda .............................................................................................................. 46 9.3.3. Insects.................................................................................................................... 47 9.3.3.1. Insect predators .............................................................................................. 48 9.3.3.2. Parasitoids ...................................................................................................... 49 9.3.3.3. Bees ................................................................................................................ 50 9.4. Rotifers and marine worms .......................................................................................... 51 9.5. Mollusca ....................................................................................................................... 51 9.6. Crustaceans................................................................................................................... 52 9.6.1. Microcrustaceans................................................................................................... 52 9.6.2. Macrocrustaceans.................................................................................................. 53 9.7. Fish and amphibians..................................................................................................... 54 9.7.1. Mosquito predatory fish, Gambusia affinis........................................................... 56 9.8. Deformed frog controversy .......................................................................................... 56 9.9. Mammalian toxicity...................................................................................................... 60 9.9.1. Humans.................................................................................................................. 60 9.9.2. Residue tolerances in animal products.................................................................. 61 9.9.3. Cattle ..................................................................................................................... 61 9.9.4. Sheep ..................................................................................................................... 63 9.9.5. Small mammals and birds ..................................................................................... 63 10. Persistence and activity in the environment ................................................................. 65 10.1. Environmental persistence ......................................................................................... 65 10.2. Persistence in water .................................................................................................... 66 10.2.1. Effect of water quality........................................................................................