Using Present Value as a Simple Approach to Compare Mosquito Larval Control Methods

Simple economic-based comparisons of source reduction and larvicide treatment are generally lacking in the mosquito control literature. The aim is to address this by developing an Excel tool that calculates the total present value (PV) of control methods. We use 15 years as the time frame, but this can be varied. Total PV is calculated based on the cost of each method at the start. A 3% discount rate is applied to recurring costs, and one-off costs are included throughout because they are part of the total PV. The data are based on information provided by mosquito control agencies in southeast Queensland, Australia. Values in the tool can be simply edited to reflect specific program characteristics. The outcome for the data used showed that source reduction is an appropriate option if maintenance is minimal. When major maintenance is needed, then larviciding may be the better option, particularly if money is the main consideration. However, if the frequency of applying larvicides increases, then source reduction becomes an increasingly attractive option.