oil into fine globules. Each pesticide was separated into three dilutions: field rate, twice

field rate, and one-half field rate. The field rate was taken from label data for each

pesticide as directed for use against scale insects. A small amount (0.5 ml) of the

pesticide working solution was dispensed into 20-ml scintillation vials. Concentrations

of active ingredient for the working solution and the amount of active ingredient residue

within the vials can be seen in Table 3-1. Vials were hand turned until the acetone or

ethanol completely evaporated leaving an insecticidal residue on the inner surface. Vials

treated with only acetone or ethanol, as well as untreated vials, were used as controls. A

single beetle was placed into a treated vial. All beetles had emerged from pupae within

the previous 14 days. Vials were sealed with cotton soaked in water allowing the beetles

to drink. Vials were placed upright in a ventilated cabinet with a fume hood and at a

constant temperature of 250 C and 80% relative humidity for 24 hours. For each treatment

of 10 beetles, 5 females and 5 males were used. Each treatment of 10 beetles was

replicated 3 times for each dosage. All trials were carried out the same day as the

pesticide was applied to the vials.

 Mortality of beetles was determined immediately after the 24-hour period. A beetle

was considered dead if it was not moving or could not right itself. Percent survivorship

was measured as the proportion of 30 beetles alive after a 24-hour exposure to the

pesticides.

Statistical Analysis

 All descriptive statistics were generated in EXCEL (Microsoft 2000). The

mortality rates for each pesticide were compared using the Student-Newman-Keuls mean

separation test (SAS Institute 2001).