Dosage Mortality Studies on Laboratory-Reared and Field-Collected Larvae of the Hickory Shuckworm12

Dosage-mortality lines were established for azinphosmethyl, diazinon, malathion, methyl parathion, and monocrotophos against field-collected and laboratory-reared larvae of Laspeyresia caryana (Fitch). Effectiveness of the test compounds from most to least toxic when topically applied to field-collected larvae with LD50 values expressed as μg of insecticide per g of larval weight were: methyl parathion 6.55 μg/g, azinphosmethyl 6.95 μg/g, monocrotophos 27.46 μg/g, malathion 65.02 μg/g, and diazinon 162.29 μg/g. The relative rank and LD50 values against laboratory-reared larvae were: azinphosmethyl 8.55 μg/g, methyl parathion 17.74 μg/g, monocrotophos 44.30 μg/g, malathion 122.94 μg/g, and diazinon 132.54 μg/g.