Toxicity, joint toxic effect and resistance monitoring to cypermethrin, alpha-cypermethrin and thiodicarb in pink bollworm Pectinophora gossypiella (Saunders)

Document Type : Original Article

Authors

Plant Protection Research Institute, Agriculture Research Center, Giza, Egypt

10.21608/jpces.2004.459470

Abstract

Toxicity of two dichlorovinyl pyrethroids, cypermethrin and alpha-cypermethrin, and the oxime-carbamate insecticide, thiodicarb, were determined against the laboratory and field male moth populations of pink bollworm, Pectinophora gossypiella (Saunders) and also, the toxicity of their mixtures at the ratio of 1:5 were measured to the field population. Toxicity data from laboratory and field populations, demonstrated that, the LC50's of cypermethrin were 0.14 and 2.85 ppm, respectively and the corresponding LC50's of alpha-cypermethrin were 0.125 and 2.96 ppm, while thiodicarb LC50 values were 5.9 and 91.5 ppm. Mixtures of pyrethroid - thiodicarb in mixing ratio of 1:5 were more effective against field population than that of their individuals. The pyrethroid toxicity in the mixture was increased from 5.18 fold for cypermethrin to 5.69 fold for alpha-cypermethrin with co-toxicity factor of 77.7 and 79.6, respectively. On the other hand, pyrethroid - thiodicarb mixtures were highly increased the toxicity of thiodicarb alone. Monitoring resistance data showed high resistance levels in the field population against cypermethrin and alpha-cypermethrin each one alone. Based on comparing with LC50 values of the laboratory population, the resistance ratio values were 20.36 and 23.68 fold, respectively, while mixing with thiodicarb decreased these levels to 3.93 fold for cypermethrin and 4.16 fold for alpha-cypermethrin.

Keywords

Journal of Pest Control and Environmental Sciences
Volume 12, Issue 1
2004
Pages 1-12

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