Background Cotton(Gossypium hirsutum L.)is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies.However,over the years quantity and quality have ...Background Cotton(Gossypium hirsutum L.)is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies.However,over the years quantity and quality have been hampered by the pest leafhopper.Leafhopper alone has been shown to cause yield losses of up to 40%.In this study,screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant,moderately resistant,sensitive and highly sensitive to leafhoppers.Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance.Based on the screening results,a total of 19 genotypes were resistant to leafhoppers,which was on par with the findings of the check KC 3.The contents of total soluble sugar,total soluble protein,and total free amino acids were significantly positively correlated with the mean grade,whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade.However,based on screening and biochemical analysis,the genotypes KC 2,JR-23,Samaru-26-T,D 4,TCH 1728,RS 253,and B-61-1862 exhibited high resistance to leafhopper.Conclusion According to the findings of this study,choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar,total soluble protein,and free amino acids may aid in the development of resistant genotypes.展开更多
Leafhoppers (jassids) are well-known pests of vegetable crops in Niger. They are often part of a parasitic complex that causes varying degrees of damage. Over the last two crop years, the Niamey region has seen a heav...Leafhoppers (jassids) are well-known pests of vegetable crops in Niger. They are often part of a parasitic complex that causes varying degrees of damage. Over the last two crop years, the Niamey region has seen a heavy outbreak of leaf hoppers on okra and guinea sorrel. These insects alone have caused spectacular damage, resulting in losses ranging from 50% to 100% of unharvested plants. Following this observation, infested fields were surveyed, specimens sampled, and the responsible species identified. Two sites were surveyed in the city of Niamey. At each site, two plots of okra and two of guinea sorrel were visited. Fifty (50) plants were randomly sampled using the double “W” method per plot. The sampled plants were used for active and passive leaf hopper capture, damage description and loss assessment. Captured leaf hoppers were identified based on their morphology observed with a binocular magnifying glass and compared with the data in the identification keys. The symptoms observed in the plots were yellowing, leaf curling and drying, stunting, abortion of flowers and immature fruit and very low production. Identification results revealed the single species Amrasca biguttula (Ishida, 1913), which can be considered a new invasive species in Niger. Further confirmation of this identification by molecular tests, the distribution of the pest in Niger and the development of appropriate control methods would yield good prospects.展开更多
【目的】旨在明确生物源和新烟碱类杀虫剂对棉叶蝉Amrasca biguttula若虫的毒力水平和田间药效,为棉叶蝉科学防治提供依据。【方法】以浸叶法在室内测定了3种生物源杀虫剂(藜芦胺、阿维菌素、苦参碱)和5种新烟碱类杀虫剂(烯啶虫胺、氯...【目的】旨在明确生物源和新烟碱类杀虫剂对棉叶蝉Amrasca biguttula若虫的毒力水平和田间药效,为棉叶蝉科学防治提供依据。【方法】以浸叶法在室内测定了3种生物源杀虫剂(藜芦胺、阿维菌素、苦参碱)和5种新烟碱类杀虫剂(烯啶虫胺、氯噻啉、呋虫胺、噻虫嗪和啶虫脒)处理24 h时对湘北棉区棉叶蝉3龄若虫的致死中浓度(median lethal concentration,LC_(50))值。基于各杀虫剂推荐使用剂量,以人工喷雾法在棉叶蝉发生盛期于2021年8月湖南桃源县棉田对0.5%藜芦胺可溶液剂(soluble concentrate,SL)(5.625 g a.i./hm^(2))、5%阿维菌素乳油(emulsifiable concentrate,EC)(10.5 g a.i./hm^(2))、2%苦参碱水剂(aqueous solution,AS)(10.5 g a.i./hm^(2))、10%烯啶虫胺AS(30 g a.i./hm^(2))、40%氯噻啉水分散粒剂(water dispersible granule,WG)(30 g a.i./hm^(2))、20%呋虫胺悬浮剂(suspension concentrate,SC)(75 g a.i./hm^(2))、30%噻虫嗪SC(33.75 g a.i./hm^(2))和5%啶虫脒EC(18 g a.i./hm^(2))进行棉叶蝉田间防效评价。【结果】室内毒力测定结果表明:处理后24 h时,8种杀虫剂对棉叶蝉3龄若虫的毒力从大到小依次为0.5%藜芦胺SL>5%阿维菌素EC>10%烯啶虫胺AS>40%氯噻啉WG>20%呋虫胺SC>2%苦参碱AS>30%噻虫嗪SC>5%啶虫脒EC,且生物源杀虫剂0.5%藜芦胺AS与5%阿维菌素EC对棉叶蝉3龄若虫的LC_(50)值分别为1.79和4.00 mg/L,其毒力均高于供试的5种新烟碱类杀虫剂。田间药效试验结果表明,0.5%藜芦胺SL对棉叶蝉的田间防效最佳,施药1 d后校正防效为91.36%,显著高于其他杀虫剂;药后7和14 d时的校正防效分别为86.14%和80.09%,仅次于20%呋虫胺SC的92.02%和86.99%,与10%烯啶虫胺AS和40%氯噻啉WG的无显著差异,但显著高于其他杀虫剂的。【结论】本研究结果表明藜芦胺和烯啶虫胺对湘北棉区棉叶蝉种群兼具较好的室内杀虫活性与田间防效。为了减少杀虫剂的不合理使用,促进化学农药与生物源农药的协同应用,建议在棉田交替使用藜芦胺与烯啶虫胺防治棉叶蝉。展开更多
文摘Background Cotton(Gossypium hirsutum L.)is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies.However,over the years quantity and quality have been hampered by the pest leafhopper.Leafhopper alone has been shown to cause yield losses of up to 40%.In this study,screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant,moderately resistant,sensitive and highly sensitive to leafhoppers.Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance.Based on the screening results,a total of 19 genotypes were resistant to leafhoppers,which was on par with the findings of the check KC 3.The contents of total soluble sugar,total soluble protein,and total free amino acids were significantly positively correlated with the mean grade,whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade.However,based on screening and biochemical analysis,the genotypes KC 2,JR-23,Samaru-26-T,D 4,TCH 1728,RS 253,and B-61-1862 exhibited high resistance to leafhopper.Conclusion According to the findings of this study,choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar,total soluble protein,and free amino acids may aid in the development of resistant genotypes.
文摘Leafhoppers (jassids) are well-known pests of vegetable crops in Niger. They are often part of a parasitic complex that causes varying degrees of damage. Over the last two crop years, the Niamey region has seen a heavy outbreak of leaf hoppers on okra and guinea sorrel. These insects alone have caused spectacular damage, resulting in losses ranging from 50% to 100% of unharvested plants. Following this observation, infested fields were surveyed, specimens sampled, and the responsible species identified. Two sites were surveyed in the city of Niamey. At each site, two plots of okra and two of guinea sorrel were visited. Fifty (50) plants were randomly sampled using the double “W” method per plot. The sampled plants were used for active and passive leaf hopper capture, damage description and loss assessment. Captured leaf hoppers were identified based on their morphology observed with a binocular magnifying glass and compared with the data in the identification keys. The symptoms observed in the plots were yellowing, leaf curling and drying, stunting, abortion of flowers and immature fruit and very low production. Identification results revealed the single species Amrasca biguttula (Ishida, 1913), which can be considered a new invasive species in Niger. Further confirmation of this identification by molecular tests, the distribution of the pest in Niger and the development of appropriate control methods would yield good prospects.
文摘【目的】旨在明确生物源和新烟碱类杀虫剂对棉叶蝉Amrasca biguttula若虫的毒力水平和田间药效,为棉叶蝉科学防治提供依据。【方法】以浸叶法在室内测定了3种生物源杀虫剂(藜芦胺、阿维菌素、苦参碱)和5种新烟碱类杀虫剂(烯啶虫胺、氯噻啉、呋虫胺、噻虫嗪和啶虫脒)处理24 h时对湘北棉区棉叶蝉3龄若虫的致死中浓度(median lethal concentration,LC_(50))值。基于各杀虫剂推荐使用剂量,以人工喷雾法在棉叶蝉发生盛期于2021年8月湖南桃源县棉田对0.5%藜芦胺可溶液剂(soluble concentrate,SL)(5.625 g a.i./hm^(2))、5%阿维菌素乳油(emulsifiable concentrate,EC)(10.5 g a.i./hm^(2))、2%苦参碱水剂(aqueous solution,AS)(10.5 g a.i./hm^(2))、10%烯啶虫胺AS(30 g a.i./hm^(2))、40%氯噻啉水分散粒剂(water dispersible granule,WG)(30 g a.i./hm^(2))、20%呋虫胺悬浮剂(suspension concentrate,SC)(75 g a.i./hm^(2))、30%噻虫嗪SC(33.75 g a.i./hm^(2))和5%啶虫脒EC(18 g a.i./hm^(2))进行棉叶蝉田间防效评价。【结果】室内毒力测定结果表明:处理后24 h时,8种杀虫剂对棉叶蝉3龄若虫的毒力从大到小依次为0.5%藜芦胺SL>5%阿维菌素EC>10%烯啶虫胺AS>40%氯噻啉WG>20%呋虫胺SC>2%苦参碱AS>30%噻虫嗪SC>5%啶虫脒EC,且生物源杀虫剂0.5%藜芦胺AS与5%阿维菌素EC对棉叶蝉3龄若虫的LC_(50)值分别为1.79和4.00 mg/L,其毒力均高于供试的5种新烟碱类杀虫剂。田间药效试验结果表明,0.5%藜芦胺SL对棉叶蝉的田间防效最佳,施药1 d后校正防效为91.36%,显著高于其他杀虫剂;药后7和14 d时的校正防效分别为86.14%和80.09%,仅次于20%呋虫胺SC的92.02%和86.99%,与10%烯啶虫胺AS和40%氯噻啉WG的无显著差异,但显著高于其他杀虫剂的。【结论】本研究结果表明藜芦胺和烯啶虫胺对湘北棉区棉叶蝉种群兼具较好的室内杀虫活性与田间防效。为了减少杀虫剂的不合理使用,促进化学农药与生物源农药的协同应用,建议在棉田交替使用藜芦胺与烯啶虫胺防治棉叶蝉。
