Which formula is used to calculate the efficacy of an adulticide in terms of percent reduction or percent mortality?

The correct formula used to calculate the efficacy of an adulticide in terms of percent reduction or percent mortality is Abbott's formula. Abbott's formula specifically allows for the adjustment of mortality rates to reflect the effectiveness of an adulticide by factoring in the control mortality that may occur regardless of the pesticide application. This is critical in studies where a baseline mortality rate is present, allowing for a more accurate assessment of the adulticide’s effectiveness.

Mulla's formula is also utilized in the evaluation of insecticide efficacy, particularly when dealing with mortality data, but Abbott's formula is more commonly recognized in standard practices for calculating the percent reduction and percent mortality in insect control studies.

The inclusion of both Abbott's formula and Mulla's formula in the answer highlights the importance of these calculations in the field of mosquito control, as they provide a clear method for measuring how effective a treatment is against mosquito populations.

The other options either incorrectly pair formulas or suggest a non-standard approach to calculating insecticide efficacy, which does not align with widely accepted practices in the field. Thus, the combination of Abbott's formula and Mulla's formula, while useful generally, specifically highlights Abbott's formula's role in deriving accurate mortality estimates in evaluating adulticides.