Effectivity test of ethanol extract of black pepper (Piper nigrum) against mortality of Aedes aegypti and its effect on midgut morphological changes

Aedes aegypti is the vector of Dengue Hemorrhagic Fever (DHF). Dengue vector management usually depends on synthetic larvicides. However, it can lead to insect resistance and leave chemical pollutant residues. Therefore natural larvicides are needed for their environmentally friendly and do not induce insect resistance. Piper nigrum fruit is expected to contain secondary metabolites beneficial as larvicides to Aedes aegypti. This study aims to test the effectivity of the ethanol extract of Piper nigrum fruit on the mortality of Aedes aegypti larvae and determine the effect of extract exposure on larval midgut morphological changes. The study used a completely randomized design with five experimental groups and four repetitions as follows: K (aquades + 0% extract), P1 (0.25% extract), P2 (0.50% extract), P3 (0.75% extract), P4 (1% extract). Data analysis used one-way ANOVA and continued to the LSD Post hoc test. The extract's effectiveness was analyzed using the probit test and LC50 confirmation. Changes in the morphology of larval midgut were observed descriptively and presented in the form of tables and figures. The results showed that the 1% treatment resulted in the highest larval mortality of 93% and the lowest in the 0.25% treatment of 43%. The LC50 value was 2,666 based on the probit analysis. The ethanol extract of Piper nigrum fruit affected midgut morphological changes of Aedes aegypti larvae characterized by peripheral membrane damage, microvilli thinning, epithelial cell swelling and vacuolation, and basement membrane damage.