BACKGROUND： Pesticides are used to control various pests of agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their pers...BACKGROUND： Pesticides are used to control various pests of agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their persistence. Pyrethroids are synthetic derivates of pyrethrins, which are natural organic insecticides procured from the flowers of Chrysanthemum cinerariaefolium and C. coccineum. Pyrethroids are classified into two groups class Ⅰ and class Ⅱ-based on their toxicity and physical properties. These pyrethroids are now used in many synthetic insecticides and are highly specific against insects; they are generally used against mosquitoes. The prominent site of insecticidal action ofpyrethroids is the voltage-sensitive sodium channels. METHODS and RESULTS： Pyrethroids are found to be stable, and they persist in the environment for a long period. This article provides an overview of the different classes, structure, and insecticidal properties of pyrethroid. Furthermore, the toxicity of pyrethroids is also discussed with emphasis on bioremediation to alleviate pollution. CONCLUSIONS： The article focuses on various microorganisms used in the degradation ofpyrethroids, the molecular basis of degradation, and the role of carboxylesterase enzymes and genes in the detoxification of pyrethroid.展开更多
A series of field trials were conducted in a commercial food storage facility to evaluate exposure of stored-product insects to aerosol formulations of synergized pyrethrins and the insect growth regulator methoprene....A series of field trials were conducted in a commercial food storage facility to evaluate exposure of stored-product insects to aerosol formulations of synergized pyrethrins and the insect growth regulator methoprene. When adults of Tribolium castaneum （Herbst）, the red flour beetle, and Tribolium confusum （Jacqueline DuVal）, the confused flour beetle were exposed with and without a food source to synergized pyrethrin aerosol, there was no difference in adult mortality with respect to availability of food at either 7 or 14 days after exposure （P≥0.05）. However, mortality was lower in T. confusum （40.4% and 79.3% with flour at 7 and 14 days, 38.9% and 84.8% without flour at 7 and 14 days） compared to T. castaneum （96.5% and 99.8% with flour at 7 and 14 days, 91.0% and 98.7% without flour at 7 and 14 days）. Few late-stage larvae and pupae of either species exposed to the pyrethrin aerosol emerged as adults. In tests with methoprene aerosol, adult emergence of exposed 3- and 4-week-old larvae of T. confusum was less than 2%. Only 0.3% of 4-week-old larvae of T. castaneum exposed in open and obstructed areas emerged as adults. Emergence of adults from eggs of Plodia interpunctella （Hubner）, the Indianmeal moth, embedded in culture media and exposed to the methoprene aerosol was 13.2%±3.5%. Results show that the aerosols evaluated in our study could give effective control of some of the major storedproduct insect pests in commercial food storage facilities, and may offer an alternative to fumigation.展开更多
文摘BACKGROUND： Pesticides are used to control various pests of agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their persistence. Pyrethroids are synthetic derivates of pyrethrins, which are natural organic insecticides procured from the flowers of Chrysanthemum cinerariaefolium and C. coccineum. Pyrethroids are classified into two groups class Ⅰ and class Ⅱ-based on their toxicity and physical properties. These pyrethroids are now used in many synthetic insecticides and are highly specific against insects; they are generally used against mosquitoes. The prominent site of insecticidal action ofpyrethroids is the voltage-sensitive sodium channels. METHODS and RESULTS： Pyrethroids are found to be stable, and they persist in the environment for a long period. This article provides an overview of the different classes, structure, and insecticidal properties of pyrethroid. Furthermore, the toxicity of pyrethroids is also discussed with emphasis on bioremediation to alleviate pollution. CONCLUSIONS： The article focuses on various microorganisms used in the degradation ofpyrethroids, the molecular basis of degradation, and the role of carboxylesterase enzymes and genes in the detoxification of pyrethroid.
文摘A series of field trials were conducted in a commercial food storage facility to evaluate exposure of stored-product insects to aerosol formulations of synergized pyrethrins and the insect growth regulator methoprene. When adults of Tribolium castaneum （Herbst）, the red flour beetle, and Tribolium confusum （Jacqueline DuVal）, the confused flour beetle were exposed with and without a food source to synergized pyrethrin aerosol, there was no difference in adult mortality with respect to availability of food at either 7 or 14 days after exposure （P≥0.05）. However, mortality was lower in T. confusum （40.4% and 79.3% with flour at 7 and 14 days, 38.9% and 84.8% without flour at 7 and 14 days） compared to T. castaneum （96.5% and 99.8% with flour at 7 and 14 days, 91.0% and 98.7% without flour at 7 and 14 days）. Few late-stage larvae and pupae of either species exposed to the pyrethrin aerosol emerged as adults. In tests with methoprene aerosol, adult emergence of exposed 3- and 4-week-old larvae of T. confusum was less than 2%. Only 0.3% of 4-week-old larvae of T. castaneum exposed in open and obstructed areas emerged as adults. Emergence of adults from eggs of Plodia interpunctella （Hubner）, the Indianmeal moth, embedded in culture media and exposed to the methoprene aerosol was 13.2%±3.5%. Results show that the aerosols evaluated in our study could give effective control of some of the major storedproduct insect pests in commercial food storage facilities, and may offer an alternative to fumigation.
