[ Objective] To overcome the resistance of Phytophthora parasitica var. nicotianae against metalaxyl and effectively control its damage, new efficient complex agent of metalaxyl was studied and developed. [ Method] Th...[ Objective] To overcome the resistance of Phytophthora parasitica var. nicotianae against metalaxyl and effectively control its damage, new efficient complex agent of metalaxyl was studied and developed. [ Method] The toxieities of nine fungicides against P. parasitica were measured using growth rate method. On this basis, the fungicides with good effects were selected to compound with metalaxyl, and the optimum complex ratio was confirmed. [Result] The toxicity of metalaxyl was the strongest with EC50 of 2. 130 5μg/ml; followed by carbendazim, mancezeb and dimethomorph with EC50 of 2.357 9, 2.639 8 and 2. 778 8 μg/ml. The effect of cyazofamid was the poorest with EC50 of 6. 278 8 μg/ml. The optimum complex ratios of dimethomorph, carbendazim and mancezeb with metalaxyl were 40： 60, 30：70 and 20： 80, and their co-toxicity coefficients were 138.80,124.25 and 115.00, respectively. [ Conclusion] The complex agents had application and promotion value, which could be used to carry out further field trials.展开更多
[Objective] This study aimed to investigate the resistance to different fungicides in Phytophthora parasitica var. nicotianae. [Method] Under indoor incubation conditions, the resistance to dimethomorph, metalaxyl-man...[Objective] This study aimed to investigate the resistance to different fungicides in Phytophthora parasitica var. nicotianae. [Method] Under indoor incubation conditions, the resistance to dimethomorph, metalaxyl-mancozeb, propamocarb and ovraclostrobin.dimethomorph in P. parasitica strain isolated from Zhenyuan County in Qiandongnan State was analyzed with colony growth measurement method. [Result] P. parasitica exhibited different levels of sensitivity to four fungicides. To be specific, P. parasitica exhibited the highest resistance to dimethomorph, and ECho reached 1.19 μg/ml. [Conclusion] In Zhenyuan tobacco-growing area, long-term single use of dimethomorph possesses certain resistance risk in prevention and control of black shank disease.展开更多
Foot and root rot caused by Phytophthora parasitica is a substantial threat to citrus cultivation,affecting both yield and quality.Thus,rapid and accurate detection of P.parasitica plays an important role in disease m...Foot and root rot caused by Phytophthora parasitica is a substantial threat to citrus cultivation,affecting both yield and quality.Thus,rapid and accurate detection of P.parasitica plays an important role in disease management.The aim of this study was to develop a simple diagnostic method to detect P.parasitica infection by combining recombinase polymerase amplification and lateral flow strips(LF-RPA).To establish the LF-RPA assay of P.parasitica,the primers and probe designed based on the Ypt1 gene were tested for specificity to P.parasitica,which showed no cross-reactivity with DNAs of other related oomycete species.The LF-RPA assay detected the amount of genomic DNA of P.parasitica which was as low as 1 pg.To make the LF-RPA assay useful in low-resource settings,four simplified DNA extraction methods were compared,after which the LF-RPA assay was applied,with no specialized equipment,to analyze a diverse range of citrus tissues by using a simplified PEG-NaOH method for DNA extraction.This method was successful in detecting P.parasitica in infected plant samples within 30 min.Combining the LF-RPA assay and a simplified DNA extraction method could be a potential detection test for P.parasitica,especially in areas with limited resources.展开更多
基金Supported by Key Project of Sichuan Education Department "Study on Physiological Race of Tobacco Black Shank in Liangshan and Resistance Evaluation of Tobacco Germplasm Resources in Sichuan Province"(08ZA032)~~
文摘[ Objective] To overcome the resistance of Phytophthora parasitica var. nicotianae against metalaxyl and effectively control its damage, new efficient complex agent of metalaxyl was studied and developed. [ Method] The toxieities of nine fungicides against P. parasitica were measured using growth rate method. On this basis, the fungicides with good effects were selected to compound with metalaxyl, and the optimum complex ratio was confirmed. [Result] The toxicity of metalaxyl was the strongest with EC50 of 2. 130 5μg/ml; followed by carbendazim, mancezeb and dimethomorph with EC50 of 2.357 9, 2.639 8 and 2. 778 8 μg/ml. The effect of cyazofamid was the poorest with EC50 of 6. 278 8 μg/ml. The optimum complex ratios of dimethomorph, carbendazim and mancezeb with metalaxyl were 40： 60, 30：70 and 20： 80, and their co-toxicity coefficients were 138.80,124.25 and 115.00, respectively. [ Conclusion] The complex agents had application and promotion value, which could be used to carry out further field trials.
文摘[Objective] This study aimed to investigate the resistance to different fungicides in Phytophthora parasitica var. nicotianae. [Method] Under indoor incubation conditions, the resistance to dimethomorph, metalaxyl-mancozeb, propamocarb and ovraclostrobin.dimethomorph in P. parasitica strain isolated from Zhenyuan County in Qiandongnan State was analyzed with colony growth measurement method. [Result] P. parasitica exhibited different levels of sensitivity to four fungicides. To be specific, P. parasitica exhibited the highest resistance to dimethomorph, and ECho reached 1.19 μg/ml. [Conclusion] In Zhenyuan tobacco-growing area, long-term single use of dimethomorph possesses certain resistance risk in prevention and control of black shank disease.
基金This work was funded by grants from the Fundamental Research Funds for the Central Universities,China(KYT202001 and JCQY201901)the Special Fund for Agro-scientific Research in the Public Interest,China(201503112).
文摘Foot and root rot caused by Phytophthora parasitica is a substantial threat to citrus cultivation,affecting both yield and quality.Thus,rapid and accurate detection of P.parasitica plays an important role in disease management.The aim of this study was to develop a simple diagnostic method to detect P.parasitica infection by combining recombinase polymerase amplification and lateral flow strips(LF-RPA).To establish the LF-RPA assay of P.parasitica,the primers and probe designed based on the Ypt1 gene were tested for specificity to P.parasitica,which showed no cross-reactivity with DNAs of other related oomycete species.The LF-RPA assay detected the amount of genomic DNA of P.parasitica which was as low as 1 pg.To make the LF-RPA assay useful in low-resource settings,four simplified DNA extraction methods were compared,after which the LF-RPA assay was applied,with no specialized equipment,to analyze a diverse range of citrus tissues by using a simplified PEG-NaOH method for DNA extraction.This method was successful in detecting P.parasitica in infected plant samples within 30 min.Combining the LF-RPA assay and a simplified DNA extraction method could be a potential detection test for P.parasitica,especially in areas with limited resources.
