The western flower thrips, Frankliniella occidentalis, is one of the most destructive sucking pests of vegetables, fruits and ornamental crops in China. Spinosad is one of the most commonly used insecticides to manage...The western flower thrips, Frankliniella occidentalis, is one of the most destructive sucking pests of vegetables, fruits and ornamental crops in China. Spinosad is one of the most commonly used insecticides to manage thrips. To assess the incidence of spinosad resistance in F. occidentalis field populations in eastern China, survival rates for 24 different populations were compared with those of a susceptible laboratory strain. All populations showed significantly higher resistance to spinosad compared with the control as determined by comparing median lethal concentrations. Two populations from Shouguang and Liaocheng in Shandong Province were classified as having moderate and high levels of resistance to spinosad with a mean resistance ratio of 17.0 and 89.2, respectively. Our research indicates a widespread reduction in spinosad efficacy for controlling F. occidentalis field populations, and that resistance management strategies should be implemented as soon as practicable, to reduce the potential of progressive resistance development and loss of efficacy.展开更多
The effects of glucose and inorganic phosphate on mycelium growth and spinosad production with Saccharopolyspora spinosa were studied. The results showed that the increase of glucose concentration from 18.6g·L^-1...The effects of glucose and inorganic phosphate on mycelium growth and spinosad production with Saccharopolyspora spinosa were studied. The results showed that the increase of glucose concentration from 18.6g·L^-1 to 58.8g·L^-1 could promote the mycelium growth and spinosad production. And when the glucose con- centration increased from 58.8g·L^-1 to 79.6g·L^-1, no obvious change was detected but a slight drop in spinosad production was observed, whereas, when the glucose concentration increased from 79.6g·L^-1 to 115.3g·L^-1, substantial decrease in both mycelium growth and spinosad production occurred. The increase of phosphate concentra- tion from 3.68mmol·L^-1 to 29.41mmol·L^-1 rendered corresponding increase in mycelium growth and spinosad production. When phosphate concentration increased from 29.41mmol·L^-1 to 44.12mmol·L^-1, mycelium growth slightly increased and spinosad production dropped, while when phosphate concentration increased from 44.12mmol·L^-1 to 57.62mmol·L^-1, both mycelium growth and spinosad production decreased sharply. Conclusively, the optimal initial concentration of glucose and phosphate is 58.8g·L^-1 and 29.41mmol·L^-1, respectively. The spinosad fermentation in the production medium containing 58.8g·L^-1 glucose and 29.41mmol·L^-1 phosphate was scaled up in 5-L fermentation and the spinosad production reached 507mg·L^-1, which was 28% higher thar that in the flask fermentation.展开更多
Objective:To investigate the larvicidal and pupicidal activity of spinosad against Anopheles stephensi Listen.Methods:Spinosad from the actinomycete,Saccharopolyspora spinosa was tested against Anopheles stephensi at ...Objective:To investigate the larvicidal and pupicidal activity of spinosad against Anopheles stephensi Listen.Methods:Spinosad from the actinomycete,Saccharopolyspora spinosa was tested against Anopheles stephensi at different concentrations（0.01,0.02,0.04,0.06 and 0.08 ppm.）, and against first to fourth instar larvae and pupae.Results:The larval mortality ranged from 36.1±1.7 in（0.01 ppm） to 79.3±1.8（0.08 ppm） the first instar larva.The LC<sub>50</sub> and LC<sub>90</sub> values of first, second,third and fourth instar larva were 0.001,0.031,0.034,0.036 and 0.0113,0.102,0.111,0.113, respectively.The pupal mortality ranged from 33.0±2.0（0.01 ppm） to 80.0±0.9（0.08 ppm）.The LC<sub>50</sub> and LC<sub>90</sub> values were 0.028 and 0.1020,respectively.The reduction percentage of Anopheles larvae was 82.7%,91.4%and 96.0%after 24,48,72 hours,respectively,while more than 80% reduction was observed after 3 weeks.Conclusions:In the present study spinosad effectively caused mortality of mosquito larvae in both the laboratory and field trial.It is predicted that spinosad is likely to be an effective larvicide for treatment of mosquito breeding sites.展开更多
Spinosad(spinosyns A and D)is a highly effective and environmentally friendly insecticide widely used for pest control.However,the difficulty of genetic manipulation in the original strain,Saccharopolyspora spinosa,ha...Spinosad(spinosyns A and D)is a highly effective and environmentally friendly insecticide widely used for pest control.However,the difficulty of genetic manipulation in the original strain,Saccharopolyspora spinosa,has hindered improvements in fermentation yields using synthetic biology methods.Additionally,there is a lack of simple and effective methods for enhancing the production of polyketide natural products derived from slow-growing rare actinomycetes.In this study,we developed a doubly transposition and site-specific recombina-tion(dTSR)approach to insert bacterial attachment sites(attB)and two copies of spinosad biosynthetic gene cluster(spn BGC)into various chromosomal locations of Saccharopolyspora erythraea,thereby generating het-erologous production strains for screening of spinosyn producers with improved yields.Engineered strains from the first round of TSR breeding produced spinosad at levels ranging from 5.6 to 30.5 mg/L.The second round of TSR breeding produced engineered strains with increased yields,with the highest spinosad production reaching 137.1±10.9 mg/L.These results indicated that(1)the dTSR approach could efficiently generate initial het-erologous strains with significantly improved spinosad production,and(2)the dTSR approach enabled random integration of a second copy of spn BGC into various chromosomal locations in Sac.erythraea,thereby further increasing heterologous spinosad production to high levels.This study provides a simple,rational,and efficient approach to improve the heterologous production of polyketide natural products in rare actinomycetes.展开更多
Microorganisms are often likened to complex production workshops.In Saccharopolyspora spinosa(S.spinosa),the biosynthesis of spinosad is a production line within its intricate workshop.Optimizing the entire production...Microorganisms are often likened to complex production workshops.In Saccharopolyspora spinosa(S.spinosa),the biosynthesis of spinosad is a production line within its intricate workshop.Optimizing the entire production environment and reducing unnecessary metabolic flow is essential to increasing spinosad yield.Pyruvate serves as a crucial precursor for spinosad biosynthesis.Previous studies revealed that the pyc gene is highly expressed in the gluconeogenic pathway,leading to a pyruvate shunt.By downregulating pyc,we enhanced spinosad yield,although the improvement was below expectations.We speculated that most of the accumulated pyruvate following the pyc knockdown entered some synthetic pathways unrelated to spinosad.Through metabolic pathway and qRT-PCR analyses,we found that the expression levels of gltA1 and atoB3 within the pyruvate metabolic tributary,including the TCA cycle and ethylmalonyl-CoA pathway,were significantly increased in the pyc knockdown strain.The combined knockdown of these three genes optimized the spinosad production line,increasing its yield to 633.1±38.6 mg/L,representing a 199.4%increase.This study identifies three key genes for optimizing spinosad biosynthesis and offers insights into gene screening and the efficient construction of Spinosad-producing strains.展开更多
The TetR family of regulators are an important group of transcription regulators that regulate diverse cellular processes in prokaryotes.In this study,we found that XNR_0706,a TetR family regulator,controlled the expr...The TetR family of regulators are an important group of transcription regulators that regulate diverse cellular processes in prokaryotes.In this study,we found that XNR_0706,a TetR family regulator,controlled the expression of XNR_0345,XNR_0454,XNR_0513 and XNR_1438 putatively involved in fatty acidβ-oxidation by interacting with the promoter regions in Streptomyces albus B4.The transcription level of these four genes was downregulated in XNR_0706 deletion strain(ΔXNR_0706)and restored by XNR_0706 complementation inΔ0706/pIB-0706,demonstrating that XNR_0706 was a positive transcriptional regulator of the genes.With toxic long-chain fatty acids addition in TSB media,deletion of XNR_0706 caused significantly poor growth,whereas XNR_0706 complementation increased the utilization of additional fatty acids,resulting in restored growth.Fatty acidβ-oxidation is one source of acetyl-and malonyl-CoA precursors for polyketides biosynthesis in actino-bacteria.Overexpression of XNR_0706 in B4/spnNEW,a spinosad heterologous expression strain derived from S.albus B4,increased spinosad yield by 20.6%.Additionally,supplement of 0.3 g/L fatty acids resulted in a further 42.4%increase in spinosad yield.Our study reveals a regulatory mechanism in long-chain fatty acids metabolism in S.albus and these insights into the molecular regulation ofβ-oxidation by XNR_0706 are instrumental for increasing secondary metabolites in actinobacteria.展开更多
Cross-resistance, resistance mechanisms, and mode of inheritance of spinosad resistance were studied in the western flower thrip, Frankliniella occidentalis （Pergande）. Spinosad （naturalyte insecticide） showed low...Cross-resistance, resistance mechanisms, and mode of inheritance of spinosad resistance were studied in the western flower thrip, Frankliniella occidentalis （Pergande）. Spinosad （naturalyte insecticide） showed low cross-resistance to prothiophos （organophosphorus insecticide） and chlorphenapyr （respiratory inhibitor） showed some cross-resistance to thiocyclam （nereistoxin）. The synergists PBO （piperonyl butoxide）, DEM （diethyl maleate）, and DEF （s,s,s-tributyl phosphorotrithioate） did not show any synergism on the toxicity of spinosad in the resistant strain （ICS）, indicating that metabolic- mediated detoxification was not responsible for the spinosad resistance, suggesting that spinosad may reduce sensitivity of the target site： the nicotinic acetylcholine receptor and GABA receptor. Following reciprocal crosses, dose-response lines and dominance ratios indicated that spinosad resistance was incompletely dominant and there were no maternal effects. The results of backcross showed that spinosad resistance did not fit a single-gene hypothesis, suggesting that resistance was influenced by several genes.展开更多
To promote spinosad biosynthesis by improving the limited oxygen supply during high-density fermentation of Saccharopolyspora spinosa, the open reading frame of the Vitreoscilla hemoglobin gene was placed under the co...To promote spinosad biosynthesis by improving the limited oxygen supply during high-density fermentation of Saccharopolyspora spinosa, the open reading frame of the Vitreoscilla hemoglobin gene was placed under the control of the promoter for the erythromycin resistance gene by splicing using overlapping extension PCR. This was cloned into the integrating vector pSET152, yielding the Vitreoscilla hemoglobin gene expression plasmid pSET152EVHB. This was then introduced into S. spinosa SP06081 by conjugal transfer, and integrated into the chromosome by site-specific recombination at the integration site ФC31 on pSET152EVHB. The resultant conjugant, S. spinosa S078-1101, was genetically stable. The integration was further confirmed by PCR and Southern blotting analysis. A carbon monoxide differential spectrum assay showed that active Vitreoscilla hemoglobin was successfully expressed in S. spinosa S078-1101. Fermentation results revealed that expression of the Vitreoscilla hemoglobin gene significantly promoted spinosad biosynthesis under normal oxygen and moderately oxygen-limiting conditions （P〈0.01）. These findings demonstrate that integrating expression of the Vitreoscilla hemoglobin gene improves oxygen uptake and is an effective means for the genetic improvement of S. spinosa fermentation. Saccharopolyspora spinosa, spinosad, Vitreoscilla hemoglobin, integrating vector, homologous recombination展开更多
In January 2005, the United States Environmental Protection Agency registered spinosad as a stored grain protectant. No referenced data on the efficacy of spinosad on corn in suppressing major stored-grain insects hav...In January 2005, the United States Environmental Protection Agency registered spinosad as a stored grain protectant. No referenced data on the efficacy of spinosad on corn in suppressing major stored-grain insects have been published. In this paper, we evaluated the efficacy of spinosad against seven major stored-grain insects on shelled corn in the laboratory. Insect species tested were the red flour beetle, Tribolium castaneum （Jacquelin duVal）; rusty grain beetle, Cryptolestesferrugineus （Stephens）; lesser grain borer, Rhyzopertha dominica （F.）; sawtoothed grain beetle, Oryzaephilus surinamensis （L.）; rice weevil, Sitophilus oryzae （L.）; maize weevil, Sitophilus zeamais （Motschulsky）; and Indian meal moth, Plodia interpunctella （Htibner）. Corn kernels were treated with spinosad at 0, 0. 1, 0.5, 1, and 2 active ingredient （a.i.） mg/kg for controlling the seven species. Beetle adults or P. interpunctella eggs were introduced into each container holding 100 g of untreated or insecticide-treated corn. The seven insect species survived well on the control treatment, produced 28 to 336 progeny, and caused significant kernel damage after 49 days. On spinosad-treated corn, adult mortality of C. ferrugineus, R. dominica, 0. surinamensis, S. oryzae, and S. zeamais was 〉 98% at 1 and 2 mg/kg after 12 days. Spinosad at≥ 0.5 mg/kg completely suppressed egg-to-larval survival after 21 days and egg-to-adult emergence of P. interpunctella after 49 days, whereas 16% T. castaneum adults survived at 1 mg/kg after 12 days. Spinosad at 1 or 2 mg/kg provided complete or near complete suppression of progeny production and kernel damage of all species after 49 days. Our results indicate that spinosad at the current labeled rate of 1 mg/kg is effective against the seven stored-grain insect pests on corn.展开更多
基金financially supported by the National Natural Science Foundation of China (31371942)the National Key Research and Development Program,China (2016YFC1200600)the Ministry of Science and Technology,China
文摘The western flower thrips, Frankliniella occidentalis, is one of the most destructive sucking pests of vegetables, fruits and ornamental crops in China. Spinosad is one of the most commonly used insecticides to manage thrips. To assess the incidence of spinosad resistance in F. occidentalis field populations in eastern China, survival rates for 24 different populations were compared with those of a susceptible laboratory strain. All populations showed significantly higher resistance to spinosad compared with the control as determined by comparing median lethal concentrations. Two populations from Shouguang and Liaocheng in Shandong Province were classified as having moderate and high levels of resistance to spinosad with a mean resistance ratio of 17.0 and 89.2, respectively. Our research indicates a widespread reduction in spinosad efficacy for controlling F. occidentalis field populations, and that resistance management strategies should be implemented as soon as practicable, to reduce the potential of progressive resistance development and loss of efficacy.
文摘The effects of glucose and inorganic phosphate on mycelium growth and spinosad production with Saccharopolyspora spinosa were studied. The results showed that the increase of glucose concentration from 18.6g·L^-1 to 58.8g·L^-1 could promote the mycelium growth and spinosad production. And when the glucose con- centration increased from 58.8g·L^-1 to 79.6g·L^-1, no obvious change was detected but a slight drop in spinosad production was observed, whereas, when the glucose concentration increased from 79.6g·L^-1 to 115.3g·L^-1, substantial decrease in both mycelium growth and spinosad production occurred. The increase of phosphate concentra- tion from 3.68mmol·L^-1 to 29.41mmol·L^-1 rendered corresponding increase in mycelium growth and spinosad production. When phosphate concentration increased from 29.41mmol·L^-1 to 44.12mmol·L^-1, mycelium growth slightly increased and spinosad production dropped, while when phosphate concentration increased from 44.12mmol·L^-1 to 57.62mmol·L^-1, both mycelium growth and spinosad production decreased sharply. Conclusively, the optimal initial concentration of glucose and phosphate is 58.8g·L^-1 and 29.41mmol·L^-1, respectively. The spinosad fermentation in the production medium containing 58.8g·L^-1 glucose and 29.41mmol·L^-1 phosphate was scaled up in 5-L fermentation and the spinosad production reached 507mg·L^-1, which was 28% higher thar that in the flask fermentation.
文摘Objective:To investigate the larvicidal and pupicidal activity of spinosad against Anopheles stephensi Listen.Methods:Spinosad from the actinomycete,Saccharopolyspora spinosa was tested against Anopheles stephensi at different concentrations（0.01,0.02,0.04,0.06 and 0.08 ppm.）, and against first to fourth instar larvae and pupae.Results:The larval mortality ranged from 36.1±1.7 in（0.01 ppm） to 79.3±1.8（0.08 ppm） the first instar larva.The LC<sub>50</sub> and LC<sub>90</sub> values of first, second,third and fourth instar larva were 0.001,0.031,0.034,0.036 and 0.0113,0.102,0.111,0.113, respectively.The pupal mortality ranged from 33.0±2.0（0.01 ppm） to 80.0±0.9（0.08 ppm）.The LC<sub>50</sub> and LC<sub>90</sub> values were 0.028 and 0.1020,respectively.The reduction percentage of Anopheles larvae was 82.7%,91.4%and 96.0%after 24,48,72 hours,respectively,while more than 80% reduction was observed after 3 weeks.Conclusions:In the present study spinosad effectively caused mortality of mosquito larvae in both the laboratory and field trial.It is predicted that spinosad is likely to be an effective larvicide for treatment of mosquito breeding sites.
基金supported by the National Natural Science Foundation of China(No.21076148 and No.31270087)Plan of Tianjin Science and Technology Support(11ZCKFSY0100)
基金the National Key Research and Develop-ment Program of China(2022YFC2105400)the"Major Project"of Haihe Laboratory of Synthetic Biology(22HHSWSS00001)+2 种基金theTianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-CXRC-065)for financial supportWe thank Prof.Yuhui Sun for the gift of pWHU2653Prof.Linquan Bai for the gift of pLQ0050.
文摘Spinosad(spinosyns A and D)is a highly effective and environmentally friendly insecticide widely used for pest control.However,the difficulty of genetic manipulation in the original strain,Saccharopolyspora spinosa,has hindered improvements in fermentation yields using synthetic biology methods.Additionally,there is a lack of simple and effective methods for enhancing the production of polyketide natural products derived from slow-growing rare actinomycetes.In this study,we developed a doubly transposition and site-specific recombina-tion(dTSR)approach to insert bacterial attachment sites(attB)and two copies of spinosad biosynthetic gene cluster(spn BGC)into various chromosomal locations of Saccharopolyspora erythraea,thereby generating het-erologous production strains for screening of spinosyn producers with improved yields.Engineered strains from the first round of TSR breeding produced spinosad at levels ranging from 5.6 to 30.5 mg/L.The second round of TSR breeding produced engineered strains with increased yields,with the highest spinosad production reaching 137.1±10.9 mg/L.These results indicated that(1)the dTSR approach could efficiently generate initial het-erologous strains with significantly improved spinosad production,and(2)the dTSR approach enabled random integration of a second copy of spn BGC into various chromosomal locations in Sac.erythraea,thereby further increasing heterologous spinosad production to high levels.This study provides a simple,rational,and efficient approach to improve the heterologous production of polyketide natural products in rare actinomycetes.
基金supported by funding from the National Natural Science Foundation of China(31770106,32200062)the Natural Science Foundation of Hunan Province(2024JJ5258).
文摘Microorganisms are often likened to complex production workshops.In Saccharopolyspora spinosa(S.spinosa),the biosynthesis of spinosad is a production line within its intricate workshop.Optimizing the entire production environment and reducing unnecessary metabolic flow is essential to increasing spinosad yield.Pyruvate serves as a crucial precursor for spinosad biosynthesis.Previous studies revealed that the pyc gene is highly expressed in the gluconeogenic pathway,leading to a pyruvate shunt.By downregulating pyc,we enhanced spinosad yield,although the improvement was below expectations.We speculated that most of the accumulated pyruvate following the pyc knockdown entered some synthetic pathways unrelated to spinosad.Through metabolic pathway and qRT-PCR analyses,we found that the expression levels of gltA1 and atoB3 within the pyruvate metabolic tributary,including the TCA cycle and ethylmalonyl-CoA pathway,were significantly increased in the pyc knockdown strain.The combined knockdown of these three genes optimized the spinosad production line,increasing its yield to 633.1±38.6 mg/L,representing a 199.4%increase.This study identifies three key genes for optimizing spinosad biosynthesis and offers insights into gene screening and the efficient construction of Spinosad-producing strains.
基金support from the National Key Research and Development Program of China(No.2018YFA0900404).
文摘The TetR family of regulators are an important group of transcription regulators that regulate diverse cellular processes in prokaryotes.In this study,we found that XNR_0706,a TetR family regulator,controlled the expression of XNR_0345,XNR_0454,XNR_0513 and XNR_1438 putatively involved in fatty acidβ-oxidation by interacting with the promoter regions in Streptomyces albus B4.The transcription level of these four genes was downregulated in XNR_0706 deletion strain(ΔXNR_0706)and restored by XNR_0706 complementation inΔ0706/pIB-0706,demonstrating that XNR_0706 was a positive transcriptional regulator of the genes.With toxic long-chain fatty acids addition in TSB media,deletion of XNR_0706 caused significantly poor growth,whereas XNR_0706 complementation increased the utilization of additional fatty acids,resulting in restored growth.Fatty acidβ-oxidation is one source of acetyl-and malonyl-CoA precursors for polyketides biosynthesis in actino-bacteria.Overexpression of XNR_0706 in B4/spnNEW,a spinosad heterologous expression strain derived from S.albus B4,increased spinosad yield by 20.6%.Additionally,supplement of 0.3 g/L fatty acids resulted in a further 42.4%increase in spinosad yield.Our study reveals a regulatory mechanism in long-chain fatty acids metabolism in S.albus and these insights into the molecular regulation ofβ-oxidation by XNR_0706 are instrumental for increasing secondary metabolites in actinobacteria.
文摘Cross-resistance, resistance mechanisms, and mode of inheritance of spinosad resistance were studied in the western flower thrip, Frankliniella occidentalis （Pergande）. Spinosad （naturalyte insecticide） showed low cross-resistance to prothiophos （organophosphorus insecticide） and chlorphenapyr （respiratory inhibitor） showed some cross-resistance to thiocyclam （nereistoxin）. The synergists PBO （piperonyl butoxide）, DEM （diethyl maleate）, and DEF （s,s,s-tributyl phosphorotrithioate） did not show any synergism on the toxicity of spinosad in the resistant strain （ICS）, indicating that metabolic- mediated detoxification was not responsible for the spinosad resistance, suggesting that spinosad may reduce sensitivity of the target site： the nicotinic acetylcholine receptor and GABA receptor. Following reciprocal crosses, dose-response lines and dominance ratios indicated that spinosad resistance was incompletely dominant and there were no maternal effects. The results of backcross showed that spinosad resistance did not fit a single-gene hypothesis, suggesting that resistance was influenced by several genes.
基金supported by the National Basic Research Program of China (Grant Nos. 2012CB722301 and 2011CB111605)the National High Technology Research and Development Project of China (Grant No. 2011AA10A203)the National Natural Science Foundation of China (Grant No. 31070006)
文摘To promote spinosad biosynthesis by improving the limited oxygen supply during high-density fermentation of Saccharopolyspora spinosa, the open reading frame of the Vitreoscilla hemoglobin gene was placed under the control of the promoter for the erythromycin resistance gene by splicing using overlapping extension PCR. This was cloned into the integrating vector pSET152, yielding the Vitreoscilla hemoglobin gene expression plasmid pSET152EVHB. This was then introduced into S. spinosa SP06081 by conjugal transfer, and integrated into the chromosome by site-specific recombination at the integration site ФC31 on pSET152EVHB. The resultant conjugant, S. spinosa S078-1101, was genetically stable. The integration was further confirmed by PCR and Southern blotting analysis. A carbon monoxide differential spectrum assay showed that active Vitreoscilla hemoglobin was successfully expressed in S. spinosa S078-1101. Fermentation results revealed that expression of the Vitreoscilla hemoglobin gene significantly promoted spinosad biosynthesis under normal oxygen and moderately oxygen-limiting conditions （P〈0.01）. These findings demonstrate that integrating expression of the Vitreoscilla hemoglobin gene improves oxygen uptake and is an effective means for the genetic improvement of S. spinosa fermentation. Saccharopolyspora spinosa, spinosad, Vitreoscilla hemoglobin, integrating vector, homologous recombination
文摘In January 2005, the United States Environmental Protection Agency registered spinosad as a stored grain protectant. No referenced data on the efficacy of spinosad on corn in suppressing major stored-grain insects have been published. In this paper, we evaluated the efficacy of spinosad against seven major stored-grain insects on shelled corn in the laboratory. Insect species tested were the red flour beetle, Tribolium castaneum （Jacquelin duVal）; rusty grain beetle, Cryptolestesferrugineus （Stephens）; lesser grain borer, Rhyzopertha dominica （F.）; sawtoothed grain beetle, Oryzaephilus surinamensis （L.）; rice weevil, Sitophilus oryzae （L.）; maize weevil, Sitophilus zeamais （Motschulsky）; and Indian meal moth, Plodia interpunctella （Htibner）. Corn kernels were treated with spinosad at 0, 0. 1, 0.5, 1, and 2 active ingredient （a.i.） mg/kg for controlling the seven species. Beetle adults or P. interpunctella eggs were introduced into each container holding 100 g of untreated or insecticide-treated corn. The seven insect species survived well on the control treatment, produced 28 to 336 progeny, and caused significant kernel damage after 49 days. On spinosad-treated corn, adult mortality of C. ferrugineus, R. dominica, 0. surinamensis, S. oryzae, and S. zeamais was 〉 98% at 1 and 2 mg/kg after 12 days. Spinosad at≥ 0.5 mg/kg completely suppressed egg-to-larval survival after 21 days and egg-to-adult emergence of P. interpunctella after 49 days, whereas 16% T. castaneum adults survived at 1 mg/kg after 12 days. Spinosad at 1 or 2 mg/kg provided complete or near complete suppression of progeny production and kernel damage of all species after 49 days. Our results indicate that spinosad at the current labeled rate of 1 mg/kg is effective against the seven stored-grain insect pests on corn.
