Background The cryptic nature of pink bollworm Pectinophora gossypiella(Saunders)larvae enables its reduced vul-nerability to insecticidal control.Further,the development of resistance against Bacillus thuringiensis(B...Background The cryptic nature of pink bollworm Pectinophora gossypiella(Saunders)larvae enables its reduced vul-nerability to insecticidal control.Further,the development of resistance against Bacillus thuringiensis(Bt)toxins posed a serious threat to transgenic cotton cultivation.This necessitated determining the critical timing of spray applications on the control effectiveness.This study assessed the influence of egg age(freshly laid vs.three-day-old)and the loca-tion of larvae(directly exposed to the insecticide residues on the boll rind vs.burrowed inside the bolls)on insecticide control efficacy.Results The results revealed a significant decrease in the ovicidal activity of tested insecticides with an increase in the age of eggs from one day old to three days old(paired t-test,P<0.05).The larvae directly exposed to the insec-ticide residues on the boll rind were more susceptible(>80%mortality)than the larvae exposed after they had bur-rowed inside the bolls(<49%mortality).The inhibitory effects of tested insecticides on developmental biology were more pronounced in the experiment on pre-larval release insecticide treatment compared with insecticide treatment given post-larval release and entry inside the bolls.Conclusion Egg age influences the insecticide susceptibility,as does the larval location,directly exposed vs bur-rowed inside the bolls.Older eggs and the larvae that had burrowed inside the green bolls of cotton were relatively less susceptible to the insecticide treatments.The toxic effects of insecticides on egg and larval stages were primar-ily ephemeral.These findings are significant for devising a comprehensive strategy for pink bollworm management on a sustainable basis.展开更多
Background To control the boll weevil Anthonomus grandis grandis(Coleoptera:Curculionidae),a key pest of cotton in the Americas,insecticides have been intensively used to manage their populations,increasing selection ...Background To control the boll weevil Anthonomus grandis grandis(Coleoptera:Curculionidae),a key pest of cotton in the Americas,insecticides have been intensively used to manage their populations,increasing selection pressure for resistant populations.Thus,this study aimed to detect insecticide resistance and assess insecticide control failure likelihood of boll weevil populations exposed to malathion,profenophos+cypermethrin,and fipronil insecticides.Results Twelve populations of the boll weevil were collected from commercial cotton fileds of the state of Bahia,northeastern Brazil.These populations were exposed to malathion,profenophos+cypermethrin mixture,and fipronil,at their respective maximum label dose for field applications.Three replicates of 10 adult beetles were exposed to the insecticides and mortality was recorded after 24 h treatment.The control failure likelihood was determined after 48 h.Highest median lethal times(LT_(50))were observed for malathion and the profenophos+cypermethrin mixture.Resistance to at least one insecticide was detected in 11 populations;three populations were resistant to malathion and profenophos+cypermethrin;seven were resistant to all insecticides tested.The resistance levels were low(<10-fold)for the three insecticides.Among 12 populations tested,58%of them exhibited significant risk of control failure for the insecticides malathion and profenophos+cypermethrin.The insecticide fipronil was efficient for the control of the boll weevil in 83%of the populations.Conclusions The results confirm the significant risk of insecticide control failure in the boll weevil populations to the main compounds used in the region.Thus,proper insecticide resistance management plans are necessary for the boll weevil in the region,particularly for malathion and profenophos+cypermethrin insecticides.展开更多
本研究建立了QuEChERS-超高效液相色谱-串联质谱(QuEChERS-UPLC-MS/MS)同时检测甘蔗及土壤中噻虫嗪、噻虫胺、毒死蜱、吡虫啉及氯虫苯甲酰胺的农药残留分析方法,为监测甘蔗生产中的农药应用风险提供方法参考。甘蔗和土壤样品分别经0.1%...本研究建立了QuEChERS-超高效液相色谱-串联质谱(QuEChERS-UPLC-MS/MS)同时检测甘蔗及土壤中噻虫嗪、噻虫胺、毒死蜱、吡虫啉及氯虫苯甲酰胺的农药残留分析方法,为监测甘蔗生产中的农药应用风险提供方法参考。甘蔗和土壤样品分别经0.1%甲酸-乙腈和乙腈振荡提取后,采用QuEChERS方法净化,流动相为甲醇和0.2%甲酸水,采用C18色谱柱进行分离,基质匹配标准曲线外标法定量分析。结果表明:在0.01、0.1 mg/kg和1 mg/kg 3个添加水平下,目标化合物的平均回收率为81.9%~115.5%,相对标准偏差(relative standard deviations,RSD)为1.3%~11.8%,该方法在0.01~1 mg/kg范围内线性良好,决定系数R^(2)≥0.9900,定量限(limits of quantification,LOQ)为0.01 mg/kg。该方法准确、快速、灵敏度高,可满足甘蔗和土壤中噻虫嗪、噻虫胺、毒死蜱、吡虫啉及氯虫苯甲酰胺的检测方法要求。利用该方法对广西某产区的甘蔗农药残留进行监测,发现少量甘蔗样品中噻虫胺残留超标,其他目标杀虫剂在甘蔗样品中农药残留量符合农药限量安全标准。展开更多
建立了一种基于QuEChERS(Quick Easy Cheap Effective Rugged and Safe)前处理技术和超高效液相色谱-串联质谱(UHPLC-MS/MS)以及气相色谱(GC)快速检测玉米中14种草地贪夜蛾应急防治推荐用药残留的方法。通过对色谱质谱条件、提取溶剂、...建立了一种基于QuEChERS(Quick Easy Cheap Effective Rugged and Safe)前处理技术和超高效液相色谱-串联质谱(UHPLC-MS/MS)以及气相色谱(GC)快速检测玉米中14种草地贪夜蛾应急防治推荐用药残留的方法。通过对色谱质谱条件、提取溶剂、缓冲体系、净化剂、提取温度等进行优化,确定了以甲醇和0.1%甲酸+5 mmol/L乙酸铵作为流动相,0.1%(体积分数)氨水乙腈作为提取溶剂,4 g MgSO_(4)+1.5 g NaCl作为缓冲体系,-20℃冷冻离心等条件。14种杀虫剂线性关系良好,相关系数(r^(2))均不小于0.9917,检出限(S/N=3)为0.08~4.50 g/kg,定量限(N=10)为0.30~13.5μg/kg。3个加标水平下(60、100、400μg/kg)的平均回收率为75.00%~125.68%,相对标准偏差(RSD)为0.00%~14.64%。茚虫威、虫酰肼、虱螨脲等8种待测物表现为中等或强基质效应。该方法简便易操作,具有较好的灵敏度和准确度,适用于玉米中14种草地贪夜蛾应急防治推荐用药残留的快速检测。展开更多
文摘Background The cryptic nature of pink bollworm Pectinophora gossypiella(Saunders)larvae enables its reduced vul-nerability to insecticidal control.Further,the development of resistance against Bacillus thuringiensis(Bt)toxins posed a serious threat to transgenic cotton cultivation.This necessitated determining the critical timing of spray applications on the control effectiveness.This study assessed the influence of egg age(freshly laid vs.three-day-old)and the loca-tion of larvae(directly exposed to the insecticide residues on the boll rind vs.burrowed inside the bolls)on insecticide control efficacy.Results The results revealed a significant decrease in the ovicidal activity of tested insecticides with an increase in the age of eggs from one day old to three days old(paired t-test,P<0.05).The larvae directly exposed to the insec-ticide residues on the boll rind were more susceptible(>80%mortality)than the larvae exposed after they had bur-rowed inside the bolls(<49%mortality).The inhibitory effects of tested insecticides on developmental biology were more pronounced in the experiment on pre-larval release insecticide treatment compared with insecticide treatment given post-larval release and entry inside the bolls.Conclusion Egg age influences the insecticide susceptibility,as does the larval location,directly exposed vs bur-rowed inside the bolls.Older eggs and the larvae that had burrowed inside the green bolls of cotton were relatively less susceptible to the insecticide treatments.The toxic effects of insecticides on egg and larval stages were primar-ily ephemeral.These findings are significant for devising a comprehensive strategy for pink bollworm management on a sustainable basis.
基金supported by Foundation for Research Support of the State of Bahia(FAPESB)the CAPES Foundation(Brazilian Ministry of Education+1 种基金Finance Code 001)for financial supportBahia Association of Cotton Producers。
文摘Background To control the boll weevil Anthonomus grandis grandis(Coleoptera:Curculionidae),a key pest of cotton in the Americas,insecticides have been intensively used to manage their populations,increasing selection pressure for resistant populations.Thus,this study aimed to detect insecticide resistance and assess insecticide control failure likelihood of boll weevil populations exposed to malathion,profenophos+cypermethrin,and fipronil insecticides.Results Twelve populations of the boll weevil were collected from commercial cotton fileds of the state of Bahia,northeastern Brazil.These populations were exposed to malathion,profenophos+cypermethrin mixture,and fipronil,at their respective maximum label dose for field applications.Three replicates of 10 adult beetles were exposed to the insecticides and mortality was recorded after 24 h treatment.The control failure likelihood was determined after 48 h.Highest median lethal times(LT_(50))were observed for malathion and the profenophos+cypermethrin mixture.Resistance to at least one insecticide was detected in 11 populations;three populations were resistant to malathion and profenophos+cypermethrin;seven were resistant to all insecticides tested.The resistance levels were low(<10-fold)for the three insecticides.Among 12 populations tested,58%of them exhibited significant risk of control failure for the insecticides malathion and profenophos+cypermethrin.The insecticide fipronil was efficient for the control of the boll weevil in 83%of the populations.Conclusions The results confirm the significant risk of insecticide control failure in the boll weevil populations to the main compounds used in the region.Thus,proper insecticide resistance management plans are necessary for the boll weevil in the region,particularly for malathion and profenophos+cypermethrin insecticides.
文摘本研究建立了QuEChERS-超高效液相色谱-串联质谱(QuEChERS-UPLC-MS/MS)同时检测甘蔗及土壤中噻虫嗪、噻虫胺、毒死蜱、吡虫啉及氯虫苯甲酰胺的农药残留分析方法,为监测甘蔗生产中的农药应用风险提供方法参考。甘蔗和土壤样品分别经0.1%甲酸-乙腈和乙腈振荡提取后,采用QuEChERS方法净化,流动相为甲醇和0.2%甲酸水,采用C18色谱柱进行分离,基质匹配标准曲线外标法定量分析。结果表明:在0.01、0.1 mg/kg和1 mg/kg 3个添加水平下,目标化合物的平均回收率为81.9%~115.5%,相对标准偏差(relative standard deviations,RSD)为1.3%~11.8%,该方法在0.01~1 mg/kg范围内线性良好,决定系数R^(2)≥0.9900,定量限(limits of quantification,LOQ)为0.01 mg/kg。该方法准确、快速、灵敏度高,可满足甘蔗和土壤中噻虫嗪、噻虫胺、毒死蜱、吡虫啉及氯虫苯甲酰胺的检测方法要求。利用该方法对广西某产区的甘蔗农药残留进行监测,发现少量甘蔗样品中噻虫胺残留超标,其他目标杀虫剂在甘蔗样品中农药残留量符合农药限量安全标准。
文摘建立了一种基于QuEChERS(Quick Easy Cheap Effective Rugged and Safe)前处理技术和超高效液相色谱-串联质谱(UHPLC-MS/MS)以及气相色谱(GC)快速检测玉米中14种草地贪夜蛾应急防治推荐用药残留的方法。通过对色谱质谱条件、提取溶剂、缓冲体系、净化剂、提取温度等进行优化,确定了以甲醇和0.1%甲酸+5 mmol/L乙酸铵作为流动相,0.1%(体积分数)氨水乙腈作为提取溶剂,4 g MgSO_(4)+1.5 g NaCl作为缓冲体系,-20℃冷冻离心等条件。14种杀虫剂线性关系良好,相关系数(r^(2))均不小于0.9917,检出限(S/N=3)为0.08~4.50 g/kg,定量限(N=10)为0.30~13.5μg/kg。3个加标水平下(60、100、400μg/kg)的平均回收率为75.00%~125.68%,相对标准偏差(RSD)为0.00%~14.64%。茚虫威、虫酰肼、虱螨脲等8种待测物表现为中等或强基质效应。该方法简便易操作,具有较好的灵敏度和准确度,适用于玉米中14种草地贪夜蛾应急防治推荐用药残留的快速检测。
