Oral toxicity of fipronil, imidacloprid and borax against Tapinoma karavaievi (Hym.: Formicidae) ant under laboratory conditions

Ants are eusocial insects of the family Formicidae and are one of the most successful insects in number and diversity. Despite their favorable impact on the ecosystem, they are sometimes regarded as serious pests due to damage to agricultural products and construction facilities. Baiting is a suitable alternative to many traditional ant control methods. In the present study, the effect of oral toxicity of fipronil, imidacloprid and borax on Tapinoma karavaievi workers was evaluated under laboratory conditions at 72, 96 and 120 hours after treatment and then the survival rate of workers treated with the LC50 of the studied compounds was compared in two weeks. According to the results, the highest oral toxicity in all three-time points was related to fipronil, imidacloprid and borax, respectively. In addition, the evaluation of the effect of pesticides on the survival of workers showed a faster control of workers treated with the LC50 of fipronil (2.46 mg ai L-1) compared to imidacloprid (32.61 mg ai L-1) and borax (2654.4 mg ai L-1). The results showed that 90% effectiveness of fipronil and imidacloprid occurred on days 7 and 11 after treatment, respectively, and it seems that 90% effectiveness of borax will probably take place in the third week after treatment. In general, the current study showed that all three studied pesticides have sufficient potential to control workers and the selection of the most suitable pesticide depends on considering the pesticide concentration, strategy of control and attention to the side effects of pesticides.