Insecticidal Activity of Prodigiosin Pigment on Tenebrio molitor (Coleoptera: Tenebrionidae)

Microorganisms and their metabolites have the potential to provide a sustainable alternative to chemical insecticides. Serratia marcescens is an entomopathogenic bacterium that produces hydrolytic enzymes and toxins. It also produces a red pigment called prodigiosin, which has a variety of biological properties. In this study, the prodigiosin pigment was extracted from S. marcescens Se9 isolate with acidified ethanol and concentrated using a rotary evaporator. The insecticidal potential on larval and adult stages of Tenebrio molitor was then investigated. It was found that the mortality rate of larvae exposed to the lowest concentration (125 ppm) of crude pigment was 5%, while the mortality rate of larvae exposed to the highest concentration (2000 ppm) was 68%. The LC50 value of the crude pigment for the larval stage was determined to be 924 ppm. On the other hand, even at the highest pigment concentration (2000 ppm), only 30% mortality was observed in adults. The LC50 value of the crude pigment for the adult stage was determined to be 4570 ppm. It was determined that the pigment had a toxic effect on the pest, but the larval stage was more sensitive than the adult stage. The study showed that prodigiosin pigment appears to be a promising biocontrol agent for use against T. molitor.