Slow release formulations of Bacillus thuringiensis israelensis (AM 65-52) and spinosyns: effectiveness against the West Nile vector Culex pipiens in Saudi Arabia

Objective: To investigate the effectiveness of slow release formulations of Bacillus thuringiensis israelensis (AM 65-52) (B. thuringiensis israelensis) and spinosyns against the West Nile vector Culex pipiens (Cx. pipiens) in Saudi Arabia. Methods: We tested slow release insecticide formulations of Natular DT, Tap 60 and VectoBac granule against II instars of Cx. pipiens larvae in 50 L laboratory arenas. Results: Slow release formulations of B. thuringiensis israelensis and spinosyns gave continuous control against Cx. pipiens for several weeks. Natular DT was more effective over Tap 60 and VectoBac granule of about 1.3 and 5.8 times, respectively. Variations in the durations of effective control among the tested slow release formulations may reflect differences in their active ingredients and the mode of action. Conclusions: Our results highlighted the effectiveness of B. thuringiensis israelensis and spinosyns against an important West Nile vector, providing baseline data to develop ecofriendly mosquito control programs in Saudi Arabia.