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
Cotton plays a crucial role in shaping Indian economy and rural livelihoods.The cotton crop is prone to numerous insect pests,necessitating insecticidal application,which increases production costs.The advent of the e...Cotton plays a crucial role in shaping Indian economy and rural livelihoods.The cotton crop is prone to numerous insect pests,necessitating insecticidal application,which increases production costs.The advent of the expression of Bacillus thuringiensis(Bt)insecticidal protein in cotton has significantly reduced the burden of pest without compromising environmental or human health.After the introduction of transgenic cotton,the cultivated area expanded to 22 million hectares,with a 64% increase in adoption by farmers worldwide.Currently,Bt cotton accounts for 93% of the cultivated cotton area in India.However,extensive use of Bt cotton has accelerated resistance development in pests like the pink bollworm.Furthermore,the overreliance on Bt cotton has reduced the use of broad-spectrum pesticides,favouring the emergence of secondary pests with significant challenges.This emphasizes the urgent necessity for developing novel pest management strategies.The high-dose and refuge strategy was initially effective for managing pest resistance in Bt cotton,but its implementation in India faced challenges due to misunderstandings about the use of non-Bt refuge crops.Although gene pyramiding was introduced as a solution,combining mono toxin also led to instances of cross-resistance.Therefore,there is a need for further exploration of biotechnological approaches to manage insect resistance in Bt cotton.Advanced biotechnological strategies,such as sterile insect release,RNA interference(RNAi)-mediated gene silencing,stacking Bt with RNAi,and genome editing using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein(CRISPR-Cas),offer promising tools for identifying and managing resistance genes in insects.Additionally,CRISPR-mediated gene drives and the development of novel biopesticides present potential avenues for effective pest management in cotton cultivation.These innovative approaches could significantly enhance the sustainability and efficacy of pest resistance management in Bt cotton.展开更多
Background:Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton.In order to enhance flower insecticidal protein expression,the conventional cultivar Sikang1(S1)an...Background:Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton.In order to enhance flower insecticidal protein expression,the conventional cultivar Sikang1(S1)and the hybrid cultivar Sikang3(S3)were used as experimental materials;the applications of selected 5 types of amino acids and 21 types of amino acids were sprayed on the flowers in 2016 and 2017 cotton growing seasons.Results:The flower Bt protein contents increased significantly under the two amino acid treatments in both cultivars,the Bt protein concentration increased by 15.2 to 25.8%compared with the control.However,no significant differences were detected between the two treatments of amino acid application.Increased amino acid and soluble protein contents,enhanced GPT,GOT,protease,and peptidase activities were observed under the amino acid application at the flowering stage.Conclusions:These results suggest that exterior application of the amino acids treatments could bolster the flower insecticidal protein expression.展开更多
Plant pests have been a major problem in agricultural production. To establish sustainable methods for plant pest control, 20 of plant material extracts were selected which were synergistic with Osthole to improve the...Plant pests have been a major problem in agricultural production. To establish sustainable methods for plant pest control, 20 of plant material extracts were selected which were synergistic with Osthole to improve the performance of the osthole existing in products. The preliminary screening results indicated that Zanthoxylum bungeanum Maxim.(Z. bungeanum Maxim) compounds exerted the highest synergism. A single dose(2 000 mg · L^(-1)) of Z. bungeanum Maxim. crude extracts was used against Plutella xyllostella(P. xyllostella), Lipaphis erysimi(L. erysimi), and Sitophilus zeamais(S. zeamais). For a further examination form Z. bungeanum Maxim., in which crude extracts were mixed with osthole at different ratios. The volume ratio of 7 : 3(Z. bungeanum Maxim. extract: osthole) exhibited a more pronounced synergistic effect, and all the values of the co-toxicity coefficients were above 120. Eight distinct compounds were derived from the ethanol crude extract from Z. bungeanum Maxim.Then, the toxicity of these components to pests, such as P. xyllostella, L. erysimi, S. zeamais, Rhizopertha dominica(R. dominica),and Tribolium castaneum Herbst(T. castaneum Herbst), was determined. The results indicated that Compound 4 and Compound 7 exerted lethal effects on pest investigation. Compound 4 had the most substantial insecticidal action, at a concentration of64 ug · mL^(-1), and a death ratio of 78.3% was achieved for P. xyllostella.展开更多
Bacillus thuringiensis(Bt)exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals.Bt becomes the most commonly used environment-friendly insecticidal microorganism.Howev...Bacillus thuringiensis(Bt)exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals.Bt becomes the most commonly used environment-friendly insecticidal microorganism.However,the insecticidal activities of different Bt strains variy significantly.Therefore,it is particularly important to compare the insecticidal activities of different strains and explore their insecticidal effector mechanisms to expand Bt insecticidal spectrum and enrich transgenic resources.Here,the insecticidal activities of Vip3Aa57 and Vip3Aa62 strains,carrying vegetative insecticidal protein-encoding genes that were inserted into the expression vector pET-21b and transformed into Escherichia coli Rosetta(DE3)strain,expressing 88 ku protein,were compared.Vip3Aa57 protein reportedly displayed body weight inhibition effect on Spodoptera exigua without affecting Heliothis armigera while Vip3Aa62 protein was known to have strong insecticidal activity against S.exigua(LC50=5.124 ng•mg^(-1)).A low H.armigera activity(LC50=870.1 ng•mg^(-1))was observed.The paraffin sectioning results showed that Vip3Aa57 protein affected S.exigua midgut cell morphology.The laser confocal microscopic imaging results showed that Vip3Aa57 bound to receptors in the midgut without damaging the midgut tissue morphology.This study would be conducive for making full use of Bt strains in the soil to compare the insecticidal activities of different Vip insecticidal genes.It could thus provide significant help in revealing the underlying insecticidal mechanisms of Vip3Aa insecticidal genes,developing new insecticidal proteins and delaying pest resistance problems.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Cotton plays a crucial role in shaping Indian economy and rural livelihoods.The cotton crop is prone to numerous insect pests,necessitating insecticidal application,which increases production costs.The advent of the expression of Bacillus thuringiensis(Bt)insecticidal protein in cotton has significantly reduced the burden of pest without compromising environmental or human health.After the introduction of transgenic cotton,the cultivated area expanded to 22 million hectares,with a 64% increase in adoption by farmers worldwide.Currently,Bt cotton accounts for 93% of the cultivated cotton area in India.However,extensive use of Bt cotton has accelerated resistance development in pests like the pink bollworm.Furthermore,the overreliance on Bt cotton has reduced the use of broad-spectrum pesticides,favouring the emergence of secondary pests with significant challenges.This emphasizes the urgent necessity for developing novel pest management strategies.The high-dose and refuge strategy was initially effective for managing pest resistance in Bt cotton,but its implementation in India faced challenges due to misunderstandings about the use of non-Bt refuge crops.Although gene pyramiding was introduced as a solution,combining mono toxin also led to instances of cross-resistance.Therefore,there is a need for further exploration of biotechnological approaches to manage insect resistance in Bt cotton.Advanced biotechnological strategies,such as sterile insect release,RNA interference(RNAi)-mediated gene silencing,stacking Bt with RNAi,and genome editing using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein(CRISPR-Cas),offer promising tools for identifying and managing resistance genes in insects.Additionally,CRISPR-mediated gene drives and the development of novel biopesticides present potential avenues for effective pest management in cotton cultivation.These innovative approaches could significantly enhance the sustainability and efficacy of pest resistance management in Bt cotton.
基金The Projects#2017YFD0201306,#2018YFD0100406 supported by the National Key R&D Program of China#31671613 supported by National Natural Science Foundation of China+1 种基金Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)Project#2016PCTS-1 supported by the Chinese academy of agricultural sciences’engineering science and technology innovation fund
文摘Background:Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton.In order to enhance flower insecticidal protein expression,the conventional cultivar Sikang1(S1)and the hybrid cultivar Sikang3(S3)were used as experimental materials;the applications of selected 5 types of amino acids and 21 types of amino acids were sprayed on the flowers in 2016 and 2017 cotton growing seasons.Results:The flower Bt protein contents increased significantly under the two amino acid treatments in both cultivars,the Bt protein concentration increased by 15.2 to 25.8%compared with the control.However,no significant differences were detected between the two treatments of amino acid application.Increased amino acid and soluble protein contents,enhanced GPT,GOT,protease,and peptidase activities were observed under the amino acid application at the flowering stage.Conclusions:These results suggest that exterior application of the amino acids treatments could bolster the flower insecticidal protein expression.
基金Supported by the Demonstration of High Efficiency and Special Economic Crop Industry Poverty Project(ZY16C05-7)2018 Innovation Engineering Project of Heilongjiang Academy of Agricultural Sciences(2018YYYF004)
文摘Plant pests have been a major problem in agricultural production. To establish sustainable methods for plant pest control, 20 of plant material extracts were selected which were synergistic with Osthole to improve the performance of the osthole existing in products. The preliminary screening results indicated that Zanthoxylum bungeanum Maxim.(Z. bungeanum Maxim) compounds exerted the highest synergism. A single dose(2 000 mg · L^(-1)) of Z. bungeanum Maxim. crude extracts was used against Plutella xyllostella(P. xyllostella), Lipaphis erysimi(L. erysimi), and Sitophilus zeamais(S. zeamais). For a further examination form Z. bungeanum Maxim., in which crude extracts were mixed with osthole at different ratios. The volume ratio of 7 : 3(Z. bungeanum Maxim. extract: osthole) exhibited a more pronounced synergistic effect, and all the values of the co-toxicity coefficients were above 120. Eight distinct compounds were derived from the ethanol crude extract from Z. bungeanum Maxim.Then, the toxicity of these components to pests, such as P. xyllostella, L. erysimi, S. zeamais, Rhizopertha dominica(R. dominica),and Tribolium castaneum Herbst(T. castaneum Herbst), was determined. The results indicated that Compound 4 and Compound 7 exerted lethal effects on pest investigation. Compound 4 had the most substantial insecticidal action, at a concentration of64 ug · mL^(-1), and a death ratio of 78.3% was achieved for P. xyllostella.
基金Supported by the National Key R&D Projects(2017YFD0201200)。
文摘Bacillus thuringiensis(Bt)exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals.Bt becomes the most commonly used environment-friendly insecticidal microorganism.However,the insecticidal activities of different Bt strains variy significantly.Therefore,it is particularly important to compare the insecticidal activities of different strains and explore their insecticidal effector mechanisms to expand Bt insecticidal spectrum and enrich transgenic resources.Here,the insecticidal activities of Vip3Aa57 and Vip3Aa62 strains,carrying vegetative insecticidal protein-encoding genes that were inserted into the expression vector pET-21b and transformed into Escherichia coli Rosetta(DE3)strain,expressing 88 ku protein,were compared.Vip3Aa57 protein reportedly displayed body weight inhibition effect on Spodoptera exigua without affecting Heliothis armigera while Vip3Aa62 protein was known to have strong insecticidal activity against S.exigua(LC50=5.124 ng•mg^(-1)).A low H.armigera activity(LC50=870.1 ng•mg^(-1))was observed.The paraffin sectioning results showed that Vip3Aa57 protein affected S.exigua midgut cell morphology.The laser confocal microscopic imaging results showed that Vip3Aa57 bound to receptors in the midgut without damaging the midgut tissue morphology.This study would be conducive for making full use of Bt strains in the soil to compare the insecticidal activities of different Vip insecticidal genes.It could thus provide significant help in revealing the underlying insecticidal mechanisms of Vip3Aa insecticidal genes,developing new insecticidal proteins and delaying pest resistance problems.
