Open AccessTOXICITY OF ORGANOPHOSPHORUS INSECTICIDES TO FOURTH‐INSTAR LARVAE OF CHIRONOMUS TEPPERI SKUSE (DIPTERA: CHIRONOMIDAE)
Author(s) -
Stevens M. M.
Publication year - 1992
Publication title -
australian journal of entomology
Language(s) - English
Resource type - Journals
eISSN - 1440-6055
pISSN - 1326-6756
DOI - 10.1111/j.1440-6055.1992.tb00519.x
Subject(s) - diazinon , chlorpyrifos , fenthion , toxicology , biology , malathion , chironomidae , instar , larva , pesticide , parathion methyl , botany , agronomy
Commercial formulations of chlorpyrifos, trichlorfon, malathion, diazinon, temephos, fenthion, chlorfenvinphos and chlorpyrifos‐methyl were bioassayed at 25 ± 1 °C against fourth‐instar larvae of the rice bloodworm, Chironomus tepperi . Chlorpyrifos was the most toxic, with an LC 50 of 1.3 ppb. The relative order of LC 50 s in ppb was (LC 50 values in brackets); chlorpyrifos (1.3) < chlorpyrifos‐methyl (2.5) < temephos (2.8) < chlorfenvinphos (6.0) < malathion (8.4) < diazinon (35.5) < trichlorfon (67.4) < fenthion (159.4). All compounds are sufficiently toxic to be effective against C. tepperi in the field, but the results suggest that some insecticides, particularly chlorpyrifos, are being applied at excessive rates.