This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at ...This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at developing methods and strategies for integrated use of Bacillus thuringiensis and Beauveria bassiana for biologically-based management of potato beetles in the northeastern USA.The described studies have resulted in 1)design of a tractor-mounted hydraulic spray system that improved targeting and consequent efficacy of microbial control agents,2)discovery of synergism between the bacterial pathogen Bacillus thuringiensis(Bt)and the fungal pathogen Beauveria bassiana(Bb),3)findings that substantial mortality of beetle larvae treated with B.bassiana during foliar spray programs did not occur until after they entered the soil to pupate,and 4)observations that spray applications made in the evening(at sunset)were significantly,but not substantially,more effective than applications made during the morning hours.These findings have led to development of a bio-based pest management system based on three spray applications made in the following order at 3-5-day intervals:Bt alone,Bt and Bb mixed,and Bb alone.This spray program,with the applications initiated at 50% egg hatch,is intended to control the actively feeding larval stages(providing protection from defoliation)and reduce survivorship to the adult stage(providing long-term control by reducing populations of overwintering adults).In the initial test of the integrated management system,beetle control and potato yields were statistically equivalent to those in plots in which the beetles were controlled with chemical insecticides.Demonstration of the effectiveness of this program will continue over the next 2-3 field seasons.展开更多
Pesticides were economically important chemicals in agriculture. Their use has permitted agricultural progress, through the eradication of harmful insect and the fight against vectors of disease. However, several stud...Pesticides were economically important chemicals in agriculture. Their use has permitted agricultural progress, through the eradication of harmful insect and the fight against vectors of disease. However, several studies question the beneficial effects of organophosphorus compounds, showing that their deregulated use causes various problems of environmental pollution and human health. The present study shows that chronic exposure to a subtoxic dose of dimethoate is likely to affect cognitive and behavioral functions of rats (both males and females). Our results show that exposure to dimethoate affects both short and long-term memory capacities. The short-term memory results are more pronounced. Treatment with nettle extract allowed a significant improvement in cognitive and behavioral performance of the rats after their exposure to dimethoate.展开更多
Developmental exposure to organophosphate insecticide is well known to induce neurobehavioral impairments, at late period. The present study aims to investigate the effects of subchronic exposure to Dimethoate, on loc...Developmental exposure to organophosphate insecticide is well known to induce neurobehavioral impairments, at late period. The present study aims to investigate the effects of subchronic exposure to Dimethoate, on locomotors skills and anxiety like behavior among wistar rat. Two groups of female’s rats are used. The intoxicated group receives daily, during five weeks, by intragastric gavage, a dose of Dimethoate dissolved in corn oil (100 mg/kg body weight). The control group receives only the corn oil. Spontaneous locomotors activity is evaluated using the Open Field test (OF) and anxiety-like behavior is measured using Elevated Plus-Maze (EPM). Dimethoate induced significant impairment of spontaneous locomotors activities, which is reflected by high decrease of number of squares crossed (SC) in OF. Females exposed to Dimethoate develop further anxiety-like response, expressed by significant reductions of the time spent in open arm of Elevated Plus-Maze.展开更多
文摘This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at developing methods and strategies for integrated use of Bacillus thuringiensis and Beauveria bassiana for biologically-based management of potato beetles in the northeastern USA.The described studies have resulted in 1)design of a tractor-mounted hydraulic spray system that improved targeting and consequent efficacy of microbial control agents,2)discovery of synergism between the bacterial pathogen Bacillus thuringiensis(Bt)and the fungal pathogen Beauveria bassiana(Bb),3)findings that substantial mortality of beetle larvae treated with B.bassiana during foliar spray programs did not occur until after they entered the soil to pupate,and 4)observations that spray applications made in the evening(at sunset)were significantly,but not substantially,more effective than applications made during the morning hours.These findings have led to development of a bio-based pest management system based on three spray applications made in the following order at 3-5-day intervals:Bt alone,Bt and Bb mixed,and Bb alone.This spray program,with the applications initiated at 50% egg hatch,is intended to control the actively feeding larval stages(providing protection from defoliation)and reduce survivorship to the adult stage(providing long-term control by reducing populations of overwintering adults).In the initial test of the integrated management system,beetle control and potato yields were statistically equivalent to those in plots in which the beetles were controlled with chemical insecticides.Demonstration of the effectiveness of this program will continue over the next 2-3 field seasons.
文摘Pesticides were economically important chemicals in agriculture. Their use has permitted agricultural progress, through the eradication of harmful insect and the fight against vectors of disease. However, several studies question the beneficial effects of organophosphorus compounds, showing that their deregulated use causes various problems of environmental pollution and human health. The present study shows that chronic exposure to a subtoxic dose of dimethoate is likely to affect cognitive and behavioral functions of rats (both males and females). Our results show that exposure to dimethoate affects both short and long-term memory capacities. The short-term memory results are more pronounced. Treatment with nettle extract allowed a significant improvement in cognitive and behavioral performance of the rats after their exposure to dimethoate.
文摘Developmental exposure to organophosphate insecticide is well known to induce neurobehavioral impairments, at late period. The present study aims to investigate the effects of subchronic exposure to Dimethoate, on locomotors skills and anxiety like behavior among wistar rat. Two groups of female’s rats are used. The intoxicated group receives daily, during five weeks, by intragastric gavage, a dose of Dimethoate dissolved in corn oil (100 mg/kg body weight). The control group receives only the corn oil. Spontaneous locomotors activity is evaluated using the Open Field test (OF) and anxiety-like behavior is measured using Elevated Plus-Maze (EPM). Dimethoate induced significant impairment of spontaneous locomotors activities, which is reflected by high decrease of number of squares crossed (SC) in OF. Females exposed to Dimethoate develop further anxiety-like response, expressed by significant reductions of the time spent in open arm of Elevated Plus-Maze.
