Joint action of cypermethrin insecticide and some natural control agents against cereals aphids and their predators | ||
| Journal of Pest Control and Environmental Sciences | ||
| Volume 7, Issue 3, December 1999, Pages 25-38 PDF (4.87 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jpces.1999.462113 | ||
| Author | ||
| A. A. M. Thabet* | ||
| Plant Protection Department, Faculty of Agriculture. Sana'a University, Republic of Yemen | ||
| Abstract | ||
| Maize and Sorghum aphid, Rhopalosiphum padi (L) and the Russian Wheat aphid, Diuraphis noxia (K.). are serious pest for several grain cereals in Yemen. The natural enemies of the Coccinellidae, Coccinella sepirmpunctata (L.) and Coccinella undecimpunctata (H.), are insect predators that can play an important role in the dynamics of aphid’s populations. The toxicity of the chemical insecticide Cypermethrin, Neem Azal, T.S. 5% (Azadirachtin indica), and Bacillus thuringiensis (H-14) were evaluated separately against the adult aphids and their predators. The results indicated that cypermethrin was the most effective insecticide tested against the adult of D. noxia (K.) aphid followed by Neem Azal T.S. 5% and B. thuringiensis, B. t. (H-14). The LC50 values were 1.10, 69.20 and 208.82 ppm, respectively. While the adult of R padi (L.) was more toloarant, where the LC50 values were 11.61, 250.10 and 286.31 ppm, respectively. Cypermethrin was the most toxic insecticide tested against the adult stage of C. undecimpunctata and C. septermpunctata predators. The LC50 values of the three insecticides were 30.00, 442.32, and 780.11ppm, respectively against C. undecimpunctata, while it was 35.12, 523.86 and 614.33 ppm, respectively against the adult of C. septermpunctata predator. The results indicated that the combinations of the B. t. (H-4) at LC25 with the LC20, LC30 of the cypermethrin resulted in potentiation or additive effects when, were tested against the adult stage of D. noxia (k.) and R. padi (L.). In conclusion, with cypermethrin combinations, the insecticide concentration can be reduced to a level which would minimize the environmental pollution and spare predators. Integration of biological and chemical insecticides, thus achieved in the present work, is one way of minimizing the environmental hazards of chemical pesticides while maintaining the efficient control of the insects pest, and postponing the onset of pest resistance due to the decreased chemical pressure. | ||
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