Abstract
Aedes aegypti (L) is the most common mosquito transmitting Dengue viruses which cause mortality to Thai population and worldwide. Used coffee grounds still contain a significant amount of caffeine and have been reported to inhibit the growth of mosquito larvae. Arabica coffee has been famously grown and consumed as beverage drink in northern parts of Thailand. The used coffee grounds each day in this area should be applied to control the mosquitos instead of throwing away as waste. None of the studies has compared the efficacy in controlling the mosquito larvae among types of roasted used coffee ground before. This study was aimed to evaluate the efficacy of three types of used roasted Arabica coffee grounds (light, medium, and dark) with different concentrations (50 mg/mL, 100 mg/mL, and 125 mg/mL) and standard mosquito larvacide, Temephos (0.01mg/mL) on mortality of the third instar of Aedes aegypti larvae. Factorial experiment arranged in complete randomized design (CRD) under laboratory was conducted. Results showed that among three types and three concentrations of roasted used coffee grounds, the light roasted used coffee grounds at the concentration of 125 mg/mL was the best in inhibiting the larvae survival. However, the temephos (0.01 mg/mL) could kill all the larvae within 10 minutes whereas the highest concentration (125 mg/mL) of light roasted used coffee ground could cause 100% mortality in the period of 24 hours after the larvae were exposed to it. The light roasted coffee presents the highest caffeine content compared to the medium or dark roasted. The amount of caffeine left in the light roasted used coffee ground could possibly have contributed to the higher efficacy in causing mortality of the mosquito larvae than other types of roasting. Therefore, light roasted used coffee grounds could be used to slow down the increase of A. aegypti populations when the outbreaks of Aedes aegypti borne diseases have not yet occurred
Keywords
Aedes aegypti larvae; Mortality rates; Types of roasting; Used coffee grounds
