Improving cotton irrigation management practices in West Texas is important for increasing farmers＇ profits and for sustainability of the Ogallala aquifer. The objective of this work was to evaluate the effects in fi...Improving cotton irrigation management practices in West Texas is important for increasing farmers＇ profits and for sustainability of the Ogallala aquifer. The objective of this work was to evaluate the effects in field controlled episodic drought conditions on cotton gas exchange. Irrigated cotton was subjected to water stress at different timings. Irrigation was interrupted at the squaring stage, early flowering stage, from three weeks at peak bloom, and from peak bloom to the crop termination. These episodic drought treatments were compared with cotton fully irrigated throughout the whole season. From 2010 to 2012, cotton cultivar FM9180 gas exchange was measured throughout the season using a LiCor-6400 portable photosynthesis system. In 2011 and 2012, measurements were also made on DP0935 cultivar. The cotton physiological parameters evaluated included photosynthesis, transpiration and temperature. From the several parameters evaluated, some relationships were presented. Episodic drought periods can affect leaf-level gas exchange and impact yield. Photosynthesis and yield were particularly sensitive to water deficit at early flowering. Despite an increase in leaf water use efficiency under water deficit, overall growth and yield were inhibited in all treatments with a stress component. Understanding the relative sensitivity at different growth stages can help with irrigation decisions when water resources are limited.展开更多
The application and spraying effect of 3 WG-1200 A air-assisted sprayer in dwarfing rootstock apple orchard were evaluated by investigating the droplet density, coverage and volume median diameter(VMD) in different ca...The application and spraying effect of 3 WG-1200 A air-assisted sprayer in dwarfing rootstock apple orchard were evaluated by investigating the droplet density, coverage and volume median diameter(VMD) in different canopy layers(2.0, 1.5, 1.0 m) and five directions(east, south, west, north and middle) of apple trees. The results showed that the droplet density was 166.99 per square centimeter, the coverage was 48.23%, and the VMD was 138.63 μm. The droplet density in different canopy layers of the trees had consistent trend with the coverage. The droplet density and coverage in the upper and middle canopy(2.0 m and 1.5 m) had no significant difference, but they were both higher than those in the lower canopy, while the VMD in different canopy layers showed an opposite trend. The change trends of the coverage and VMD in the five directions were consistent, and the values in the middle and east were the highest, followed by the north, south and west, respectively. The results indicated that droplet characteristics of the 3 WG-1200 A air-assisted sprayer met the basic requirements for pest and pathogen control. This study provides a theoretical basis and data support for the application and improvement of orchard application equipments in dwarfing rootstock apple orchard.展开更多
The rice stem borer(RSB),Chilo suppressalis,a notorious rice pest in China,has evolved a high resistance level to commonly used insecticides.Tetraniliprole,a new anthranilic diamide insecticide,effectively controls mu...The rice stem borer(RSB),Chilo suppressalis,a notorious rice pest in China,has evolved a high resistance level to commonly used insecticides.Tetraniliprole,a new anthranilic diamide insecticide,effectively controls multiple pests,including RSB.However,the potential resistance risk of RSB to tetraniliprole is still unknown.In this study,the tetraniliprole-selection(Tet-R)strain was obtained through 10 continuous generations of selection with tetraniliprole 30%lethal concentration(LC_(30)).The realized heritability(h^(2))of the Tet-R strain was 0.387,indicating that resistance of RSB to tetraniliprole developed rapidly under the continuous selection of tetraniliprole.The Tet-R strain had a high fitness cost(relative fitness=0.53).We established the susceptibility baseline of RSB to tetraniliprole(lethal concentration at LC_(50)=0.727 mg/L)and investigated the resistance level of 6 field populations to tetraniliprole.All tested strains that had resistance to chlorantraniliprole exhibited moderate-to high-level resistance to tetraniliprole(resistance ratio=27.7-806.8).Detection of ryanodine receptor(RyR)mutations showed that the Y4667C,Y4667D,I4758M,and Y4891F mutations were present in tested RSB field populations.RyR mutations were responsible for the cross-resistance between tetraniliprole and chlorantraniliprole.Further,the clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9-mediated genome-modified flies were used to study the contribution of RyR mutations to tetraniliprole resistance.The order of contribution of a single RyR mutation to tetraniliprole resistance was Y4667D>G4915E>Y4667C~~I4758M>Y4891F.In addition,the I4758M and Y4667C double mutations conferred higher tetraniliprole resistance than single Y4667C mutations.These results can guide resistance management practices for diamides in RSB and other arthropods.展开更多
Insect ryanodine receptors(RyRs)are the targets of diamide insecticides.Two point mutations G4946E and I4790M(numbering according to Plutella xylostella,PxRyR)in the transmembrane domain of the insect RyRs associated ...Insect ryanodine receptors(RyRs)are the targets of diamide insecticides.Two point mutations G4946E and I4790M(numbering according to Plutella xylostella,PxRyR)in the transmembrane domain of the insect RyRs associated with diamide resistance have so far been identified in three lepidopteran pests,P.xylostella,Tuta absoluta and Chilo suppressalis.In this study,we identified one of the known RyR target site resistance mutations(I4790M)in a field-collected population of Spodoptera exigua.The field-collected WF population of S.exigua exhibited 154 fold resistance to chlorantraniliprole when compared with the susceptible WH-S strain.Sequencing the transmembrane domains of S.exigua RyR(SeRyR)revealed that the resistant WF strain was homozygous for the 14743M mutation(corresponding to I4790M in PxRyR),whereas the G4900E allele(corresponding to G4946E of PxRyR)was not detected.The 4743M allele was introgressed into the susceptible WH-S strain by crossing WF with WH-S,followed by three rounds of backcrossing with WH-S.The introgressed strain 4743M was homozygous for the mutant 4743M allele and shared about 94%of its genetic background with that of the recipient WH-S strain.Compared with WH-S,the near-isogenic 4743M strain showed moderate levels of resistance to chlorantraniliprole(21 fold),cyantraniliprole(25 fold)and flubendiamide(22 fold),suggesting that the I4743M mutation confers medium levels of resistance to all three diamides.Genetic analysis showed diamide resistance in the 4743M strain was inherited as an autosomal and recessive trait.Results from this study have direct implications for the design of appropriate resistance monitoring and management practices to sustainably control S.exigua.展开更多
Over-expression of the cytochrome P450 CYP6CM1 gene has been associated with imidacloprid resistance in a number of Q and B biotype Bemisia tabaci laboratory strains from distinct geographical origins worldwide. We re...Over-expression of the cytochrome P450 CYP6CM1 gene has been associated with imidacloprid resistance in a number of Q and B biotype Bemisia tabaci laboratory strains from distinct geographical origins worldwide. We recently demonstrated that the Q biotype version of the CYP6CM 1 protein （CYP6CMlvQ） is capable of metabolizing imida- cloprid. Here, we show that the levels of BtCYP6CMlvQ were also elevated in laboratory- resistant strains and field-derived populations, with variable imidacloprid resistance levels, collected in Crete. High levels of CYP6CMlvQ transcripts were also determined in survivors of a heterogeneous field population, after exposure to discriminating imidacloprid dosage. Using peptide antibody-based detection assays, we demonstrated that in line with transcriptional data, the CYP6CMlvQ protein levels were higher in imidacloprid-resistant insects, which further implicates the gene as the causal factor of resistance. Finally, assess- ment of the cross-metabolism potential of CYP6CMlvQ against additional neonicotinoid molecules used for B. tabaci control revealed that clothianidin and thiacloprid, but not acetamiprid or thiamethoxam, are metabolized by the recombinant enzyme in vitro.展开更多
Abamectin resistance was selected in the vegetable leafminer, Liriomyza sativae （Blanchard） （Diptera： Agromyzidae） under laboratory conditions, and cross- resistance patterns and possible resistance mechanisms in...Abamectin resistance was selected in the vegetable leafminer, Liriomyza sativae （Blanchard） （Diptera： Agromyzidae） under laboratory conditions, and cross- resistance patterns and possible resistance mechanisms in the abamectin-resistant strains （AL-R, AF-R） were investigated. Compared with the susceptible strain （SS）, strain AL-R displayed 39-fold resistance to abamectin after 20 selection cycles during 25 generations, and strain AF-R exhibited 59-fold resistance to abamectin after 16 selection cycles during 22 generations. No cross-resistance to cyromazine was found in both abamectin-resistant strains. However, we failed to select for cyromazine resistance in L. sativae under laboratory conditions by conducting 17 selection cycles during 22 generations. However, moderate levels of cross-resistance to abamectin （6-9 fold） were observed in strains which received cyromazine treatments. Biochemical analysis showed that glutathione S-transferase （GST） activity in both abamectin-resistant strains （AL-R, AF-R） was significantly higher than in the susceptible strain （SS）, suggesting metabolically driven resistance to abamectinin L. sativae. Recommendations of mixtures or rotation of cyromazine and abamectin should be considered carefully, as consecutive cyromazine treatments may select for low-level cross-resistance to abamectin.展开更多
The Wheat dwarf virus, the causal agent of the wheat dwarf disease, is trans- mitted by leafhoppers from the genus Psammotettix and currently the main protection strategy is based on the use of insecticide treatments....The Wheat dwarf virus, the causal agent of the wheat dwarf disease, is trans- mitted by leafhoppers from the genus Psammotettix and currently the main protection strategy is based on the use of insecticide treatments. Sustainable management strategies for insect vectors should include methods that are targeted to disrupt reproductive behavior and here we investigated the mating behavior of Psammotettix alineus （Dahlbom 1850） in order to determine the role of vibrational signals in intra-specific communication and pair formation. Both genders spontaneously emit species- and sex-specific calling songs that consisted of regularly repeated pulse trains and differ primarily in pulse train duration and pulse repetition time. Females preferred the conspecific male calling song. After a coordinated exchange of pulse trains, the male approached the stationary female. During the close range courtship and also immediately prior to copulatory attempts distinct male vibrational signals associated with wing flapping and wing vibrations were recorded from the substrate. In the presence of a receptive female, competing males emitted vibrational signals most likely aimed to interfere with male-female interaction. Mated females re- gained sexual receptivity after they laid eggs. Although results suggest that the viruliferous status of insects may have an effect on vibrational songs, our current results did not reveal a significant effect of virus on leafhopper performance in mating behavior. However, this study also suggests, that detailed understanding ofplant-vecto^virus interactions relevant for vector mating behavior is essential for trying new approaches in developing future control practices against plant viruses transmitted by insect vectors.展开更多
Indaziflam is a new preemergence herbicide for the control of annual grass and broadleaf weeds in various cropping systems including pecan orchards.The objectives of this study were to（1） determine the mobility and ...Indaziflam is a new preemergence herbicide for the control of annual grass and broadleaf weeds in various cropping systems including pecan orchards.The objectives of this study were to（1） determine the mobility and dissipation of indaziflam and（2） evaluate herbicide efficacy in a flood-irrigated pecan orchard in southern New Mexico,USA.Indaziflam was applied at 0,35.5,and 73.1 g/ha in areas with（impacted） and without（unimpacted） tree injury symptoms.Soil samples were collected at 0-15,15-30,and 30-46 cm depths 25,63,90,and 125 days after the first herbicide application.Additional soil samples were collected 4,30,and 55 days after the second application.Indaziflam was detected in soil samples collected at each depth,suggesting movement with irrigation water.Indaziflam concentrations decreased with increasing soil depth and time.Indaziflam mass recoveries were greater in the unimpacted area than in the impacted area after the first and second applications.Dissipation half-lives of indaziflam in the soil ranged from 30 to 85 days for total indaziflam recovered from the entire soil profile after the first and second applications in both areas.The percent weed control was similar in the impacted and unimpacted areas for both rates of indaziflam on 25 and 53 days after application;however,on 90 days after the application,percent weed control was lower in the impacted than unimpacted area.展开更多
文摘Improving cotton irrigation management practices in West Texas is important for increasing farmers＇ profits and for sustainability of the Ogallala aquifer. The objective of this work was to evaluate the effects in field controlled episodic drought conditions on cotton gas exchange. Irrigated cotton was subjected to water stress at different timings. Irrigation was interrupted at the squaring stage, early flowering stage, from three weeks at peak bloom, and from peak bloom to the crop termination. These episodic drought treatments were compared with cotton fully irrigated throughout the whole season. From 2010 to 2012, cotton cultivar FM9180 gas exchange was measured throughout the season using a LiCor-6400 portable photosynthesis system. In 2011 and 2012, measurements were also made on DP0935 cultivar. The cotton physiological parameters evaluated included photosynthesis, transpiration and temperature. From the several parameters evaluated, some relationships were presented. Episodic drought periods can affect leaf-level gas exchange and impact yield. Photosynthesis and yield were particularly sensitive to water deficit at early flowering. Despite an increase in leaf water use efficiency under water deficit, overall growth and yield were inhibited in all treatments with a stress component. Understanding the relative sensitivity at different growth stages can help with irrigation decisions when water resources are limited.
基金Supported by Shandong Key Research and Development Program(2017CXGC0214)Tai’an Science and Technology Development Project(2017NS0091)
文摘The application and spraying effect of 3 WG-1200 A air-assisted sprayer in dwarfing rootstock apple orchard were evaluated by investigating the droplet density, coverage and volume median diameter(VMD) in different canopy layers(2.0, 1.5, 1.0 m) and five directions(east, south, west, north and middle) of apple trees. The results showed that the droplet density was 166.99 per square centimeter, the coverage was 48.23%, and the VMD was 138.63 μm. The droplet density in different canopy layers of the trees had consistent trend with the coverage. The droplet density and coverage in the upper and middle canopy(2.0 m and 1.5 m) had no significant difference, but they were both higher than those in the lower canopy, while the VMD in different canopy layers showed an opposite trend. The change trends of the coverage and VMD in the five directions were consistent, and the values in the middle and east were the highest, followed by the north, south and west, respectively. The results indicated that droplet characteristics of the 3 WG-1200 A air-assisted sprayer met the basic requirements for pest and pathogen control. This study provides a theoretical basis and data support for the application and improvement of orchard application equipments in dwarfing rootstock apple orchard.
基金funded by the National Natural Science Foundation of China to SFW(32272576)the National Key Research and Developmental Program of China(2022YFD1400900).
文摘The rice stem borer(RSB),Chilo suppressalis,a notorious rice pest in China,has evolved a high resistance level to commonly used insecticides.Tetraniliprole,a new anthranilic diamide insecticide,effectively controls multiple pests,including RSB.However,the potential resistance risk of RSB to tetraniliprole is still unknown.In this study,the tetraniliprole-selection(Tet-R)strain was obtained through 10 continuous generations of selection with tetraniliprole 30%lethal concentration(LC_(30)).The realized heritability(h^(2))of the Tet-R strain was 0.387,indicating that resistance of RSB to tetraniliprole developed rapidly under the continuous selection of tetraniliprole.The Tet-R strain had a high fitness cost(relative fitness=0.53).We established the susceptibility baseline of RSB to tetraniliprole(lethal concentration at LC_(50)=0.727 mg/L)and investigated the resistance level of 6 field populations to tetraniliprole.All tested strains that had resistance to chlorantraniliprole exhibited moderate-to high-level resistance to tetraniliprole(resistance ratio=27.7-806.8).Detection of ryanodine receptor(RyR)mutations showed that the Y4667C,Y4667D,I4758M,and Y4891F mutations were present in tested RSB field populations.RyR mutations were responsible for the cross-resistance between tetraniliprole and chlorantraniliprole.Further,the clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9-mediated genome-modified flies were used to study the contribution of RyR mutations to tetraniliprole resistance.The order of contribution of a single RyR mutation to tetraniliprole resistance was Y4667D>G4915E>Y4667C~~I4758M>Y4891F.In addition,the I4758M and Y4667C double mutations conferred higher tetraniliprole resistance than single Y4667C mutations.These results can guide resistance management practices for diamides in RSB and other arthropods.
基金This work was funded by a grant from the Ministry of Agriculture and Rural Affairs(MARA)of China(No.2016YFD0200500).
文摘Insect ryanodine receptors(RyRs)are the targets of diamide insecticides.Two point mutations G4946E and I4790M(numbering according to Plutella xylostella,PxRyR)in the transmembrane domain of the insect RyRs associated with diamide resistance have so far been identified in three lepidopteran pests,P.xylostella,Tuta absoluta and Chilo suppressalis.In this study,we identified one of the known RyR target site resistance mutations(I4790M)in a field-collected population of Spodoptera exigua.The field-collected WF population of S.exigua exhibited 154 fold resistance to chlorantraniliprole when compared with the susceptible WH-S strain.Sequencing the transmembrane domains of S.exigua RyR(SeRyR)revealed that the resistant WF strain was homozygous for the 14743M mutation(corresponding to I4790M in PxRyR),whereas the G4900E allele(corresponding to G4946E of PxRyR)was not detected.The 4743M allele was introgressed into the susceptible WH-S strain by crossing WF with WH-S,followed by three rounds of backcrossing with WH-S.The introgressed strain 4743M was homozygous for the mutant 4743M allele and shared about 94%of its genetic background with that of the recipient WH-S strain.Compared with WH-S,the near-isogenic 4743M strain showed moderate levels of resistance to chlorantraniliprole(21 fold),cyantraniliprole(25 fold)and flubendiamide(22 fold),suggesting that the I4743M mutation confers medium levels of resistance to all three diamides.Genetic analysis showed diamide resistance in the 4743M strain was inherited as an autosomal and recessive trait.Results from this study have direct implications for the design of appropriate resistance monitoring and management practices to sustainably control S.exigua.
文摘Over-expression of the cytochrome P450 CYP6CM1 gene has been associated with imidacloprid resistance in a number of Q and B biotype Bemisia tabaci laboratory strains from distinct geographical origins worldwide. We recently demonstrated that the Q biotype version of the CYP6CM 1 protein （CYP6CMlvQ） is capable of metabolizing imida- cloprid. Here, we show that the levels of BtCYP6CMlvQ were also elevated in laboratory- resistant strains and field-derived populations, with variable imidacloprid resistance levels, collected in Crete. High levels of CYP6CMlvQ transcripts were also determined in survivors of a heterogeneous field population, after exposure to discriminating imidacloprid dosage. Using peptide antibody-based detection assays, we demonstrated that in line with transcriptional data, the CYP6CMlvQ protein levels were higher in imidacloprid-resistant insects, which further implicates the gene as the causal factor of resistance. Finally, assess- ment of the cross-metabolism potential of CYP6CMlvQ against additional neonicotinoid molecules used for B. tabaci control revealed that clothianidin and thiacloprid, but not acetamiprid or thiamethoxam, are metabolized by the recombinant enzyme in vitro.
文摘Abamectin resistance was selected in the vegetable leafminer, Liriomyza sativae （Blanchard） （Diptera： Agromyzidae） under laboratory conditions, and cross- resistance patterns and possible resistance mechanisms in the abamectin-resistant strains （AL-R, AF-R） were investigated. Compared with the susceptible strain （SS）, strain AL-R displayed 39-fold resistance to abamectin after 20 selection cycles during 25 generations, and strain AF-R exhibited 59-fold resistance to abamectin after 16 selection cycles during 22 generations. No cross-resistance to cyromazine was found in both abamectin-resistant strains. However, we failed to select for cyromazine resistance in L. sativae under laboratory conditions by conducting 17 selection cycles during 22 generations. However, moderate levels of cross-resistance to abamectin （6-9 fold） were observed in strains which received cyromazine treatments. Biochemical analysis showed that glutathione S-transferase （GST） activity in both abamectin-resistant strains （AL-R, AF-R） was significantly higher than in the susceptible strain （SS）, suggesting metabolically driven resistance to abamectinin L. sativae. Recommendations of mixtures or rotation of cyromazine and abamectin should be considered carefully, as consecutive cyromazine treatments may select for low-level cross-resistance to abamectin.
文摘The Wheat dwarf virus, the causal agent of the wheat dwarf disease, is trans- mitted by leafhoppers from the genus Psammotettix and currently the main protection strategy is based on the use of insecticide treatments. Sustainable management strategies for insect vectors should include methods that are targeted to disrupt reproductive behavior and here we investigated the mating behavior of Psammotettix alineus （Dahlbom 1850） in order to determine the role of vibrational signals in intra-specific communication and pair formation. Both genders spontaneously emit species- and sex-specific calling songs that consisted of regularly repeated pulse trains and differ primarily in pulse train duration and pulse repetition time. Females preferred the conspecific male calling song. After a coordinated exchange of pulse trains, the male approached the stationary female. During the close range courtship and also immediately prior to copulatory attempts distinct male vibrational signals associated with wing flapping and wing vibrations were recorded from the substrate. In the presence of a receptive female, competing males emitted vibrational signals most likely aimed to interfere with male-female interaction. Mated females re- gained sexual receptivity after they laid eggs. Although results suggest that the viruliferous status of insects may have an effect on vibrational songs, our current results did not reveal a significant effect of virus on leafhopper performance in mating behavior. However, this study also suggests, that detailed understanding ofplant-vecto^virus interactions relevant for vector mating behavior is essential for trying new approaches in developing future control practices against plant viruses transmitted by insect vectors.
基金supported by grants from Bayer CropScienceNakayama endowment,New Mexico State University Agricultural Experiment Station,owners of the pecan orchard for support
文摘Indaziflam is a new preemergence herbicide for the control of annual grass and broadleaf weeds in various cropping systems including pecan orchards.The objectives of this study were to（1） determine the mobility and dissipation of indaziflam and（2） evaluate herbicide efficacy in a flood-irrigated pecan orchard in southern New Mexico,USA.Indaziflam was applied at 0,35.5,and 73.1 g/ha in areas with（impacted） and without（unimpacted） tree injury symptoms.Soil samples were collected at 0-15,15-30,and 30-46 cm depths 25,63,90,and 125 days after the first herbicide application.Additional soil samples were collected 4,30,and 55 days after the second application.Indaziflam was detected in soil samples collected at each depth,suggesting movement with irrigation water.Indaziflam concentrations decreased with increasing soil depth and time.Indaziflam mass recoveries were greater in the unimpacted area than in the impacted area after the first and second applications.Dissipation half-lives of indaziflam in the soil ranged from 30 to 85 days for total indaziflam recovered from the entire soil profile after the first and second applications in both areas.The percent weed control was similar in the impacted and unimpacted areas for both rates of indaziflam on 25 and 53 days after application;however,on 90 days after the application,percent weed control was lower in the impacted than unimpacted area.
