PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

The pest ants-related predicament is increasing in urban area and becoming a problem for most of the citizen. The most common approach for pest ants’ control is the application of various insecticide spray. However, the long-term insect pest control must not be dependent on synthetic insecticides with many negative effects. Repellence and insecticidal effects from plants, Citrus hystrix, Mentha piperita and Ocimum basilicum have been reputed for different type of insect pests. The combination of an effective botanical insecticide and gel bait is ideal for the treatment of insect pests. In this study, the repellence and insecticidal effects of plant extracts obtained from three plant species with various concentrations (3 x 10⁵, 5 x 10⁵, 7 x 10⁵, and 1 x 10⁶ ppm) were against common urban pest ants, Tapinoma indicum, Pheidole megacephala and Monomorium pharaonic using repellence, insecticidal and gel bait bioassays. The three plant extracts usually repel ants with the efficacy being dependent on the ants and irrespective of plant species. Repellence and mortality of ants were negatively related to the higher percentage (100% = fully repelled; -100% = fully attracted; 0% = neither repelled nor attracted) of being repelled, the lower the death will be. Moreover, the optimal doses that make the fastest mortality of ants are not consistent between the insecticidal and gel bait bioassays.