Effect of directly contact and Oral toxicity of IGR insecticides on Oryzaephilus surinamensis L. (Col., Silvanidae) in vitro

Oryzaephilus surinamensis L. (Col., Silvanidae) is one of the most important stored product pests in Iran. Regarding to environmental risks of pesticides, scientists are exploring substitute compounds with less hazard to man and environment, such as RGRs. The purpose of this project is to evaluate the efficacy of three IGR insecticides, Tebufenozide, Chromafenozide and Lofux® with two methods of oral and contact on O. surinamensis larvae in laboratory condition. Different concentrations of the above insecticides have been used on 4-5 (young) and 19-20 day-old (old) larvae. Bioassay tests showed that in oral method Lufox (LC50 =9.68) and Tebufenozide (LC50 =24.49) had the most and the least efficacy on young larvae, respectively. Lufox (LC50 =22.82) and Tebufenozide (LC50 =80.18) had also the most and the least efficacy on old larvae, respectively. The most and the least efficacy contact method, on young larvae have been induced by Lufox® (LC50 =1) and Tebufenozide (LC50 =33.9), respectively. Lufox (LC50 =29.2) and Tebufenozide (LC50 =143.03) had the most and the least efficacy on old larvae, respectively.
Based on the results obtained, the use of oral method was more effective than useing contact method. Lufox® is a mixture of chitin synthesis inhibitor and juvenile hormone mimic. This combination showed the best performans on larvae O. Surinamensis and can be used safely for controling the pest.