ISCEP 2026 At Sunway Putra Hotel 17-18 August 2026
ABSTRACT
ORAL PRESENTATION ABSTRACT
T3_07
EVALUATING THE RESIDUAL EFFICACY OF DIFFERENT INSECTICIDE FORMULATIONS AGAINST MOSQUITO VECTORS
Nurulhusna AB HAMID*, Norlaili MISRAWI, Ezita Qaisara RIDZUAN, Fatin Nur Adlina ROZAIDI, Aimi Afiqah MOHAMMADIN, Muhammad Afiq Asyraf MOHD FAIZOL, Mohamad Haziq Uzair MOHD ROSLI, Mohd Farizul MOHAMMAD FATIHI, Farah Diana ARIFFIN
Medical Entoreslogy Unit defectious Diseases Research Centre, estate for Medical Research National sites of mea Ministry of Health Malesia Setia Alam Shah Alam, Selangor Malaysia
Chemical control via residual spray is a critical component in managing vector-borne diseases. While synthetic pyrethroids like deltamethrin were historically effective, escalating development of insecticide resistance seriously threatens sustained vector management. This study evaluates the residual effectiveness of different insecticides formulations with different active ingredients against diverse vector populations. Insecticide formulations were prepared according to manufacturers' specifications. Standardized WHO Wall Deposit Bioassays were conducted every 2 weeks to observe and evaluate the mortality percentages against laboratory and wild strains of Aedes spp. Culex quinquefaciatus, and Anopheles cracens Data from 4,445 valid observations were analysed using a Generalized Linear Model (GENLIN) with a binomial distribution and logit link function, incorporating two-way interaction terms to track performance changes over time. Following one spray cycle, all factors-insecticide type, mosquito strain, time, and surface height-significantly affected mortality (p < 0.001). Each incremental day post-spraying caused a significant 7.5% reduction in overall mosquito mortality odds (OR 0.925), suggesting residual degradation. The lower surface height (40 cm) resulted in 22.4% lower mortality odds compared to the 120 cm upper level (OR = 0.776). Crucially, the model proved that insecticides lose their killing power at vastly different speeds over time, with certain formulations maintaining a more stable residual presence. Relying solely on raw mortality percentages, it can hide real mosquito resistance dynamics in the field. Insecticide longevity is highly dependent on the specific chemical formulation and targeted vector strain over time. Vector control programmes must consider local insecticide resistance status and transition toward targeted chemical rotation strategies rather than a "one-size-fits- all approach
Keywords residual spray insecticides formulation residual efficacy mortality
INTERNATIONAL SCIENTIFIC CONFERENCE ON ENTOMOLOGY AND PEST SCEP) 2005