Doses are
established for both the Bottle Bioassay and the Larval Bioassay the same
way.
Assays are
run on susceptible mosquitoes with a series of insecticide concentrations.
The data
are plotted, creating a line graph similar to that in Figure
1. Convert the absolute mortality numbers to percents so that you
will have consistent graphs that can be compared more easily.
Up to a
point, the higher the concentration of insecticide used in an assay, the
shorter length of time it takes for the insects to die. There is a concentration
at or above which mosquitoes die at a maximal rate. The lowest dosage
at which this occurs is the optimal diagnostic dosage.
This dosage
should be used in all further assays with that particular insecticide
and mosquito species.
Figure
1
Conclusion:
The diagnostic
dosage is the most useful dosage for detecting resistance.
A dose
that is too low will result in false detection of resistance.
A dose
that is too high will conceal resistance at some level.
