{"title":"A comprehensive study on occurrence records of African neglected and underutilized weed species,\u0000 \u0000 Cleome gynandra\u0000 \u0000 L. (cat's whiskers) validating the ecogeographical range expansion in West Bengal, India","authors":"Ekta Bhattacharya, Rahul Bose, Suparna Mandal Biswas","doi":"10.1111/wbm.12189","DOIUrl":"https://doi.org/10.1111/wbm.12189","url":null,"abstract":"","PeriodicalId":23536,"journal":{"name":"Weed Biology and Management","volume":"19 1","pages":"129-134"},"PeriodicalIF":1.4,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/wbm.12189","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47185292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Planning effective weed control in cropping systems requires exact appraisal of the weed intensity and duration of their competition with the crops. This 2‐year study was carried out in order to determine the critical weed control period in sesame fields. Related and relative crop yields were monitored and analyzed using a four‐parametric log‐logistic model. We recorded data from weed‐free plots and compared these with data from different periods of weed interference. In both the study years, the longer period of weed interference decreased the relative yield of sesame, whereas the yield was increased with increasing duration of the weed‐free period. A 51–78.7% decline in sesame yield was noted if the weeds were allowed to compete with the crop from planting to harvest. In the first year, the duration of the critical period for weed control (CPWC) was 177–820 growing degree days (GDD), which corresponded to 14–64 days after crop emergence (DAE), and between 170 and 837 GDD (13–64 DAE) in the second year; this was based on a 5% acceptable yield loss. The results of this study clearly elaborated that maintaining weed‐free conditions is compulsory from as early as the second week after the emergence of sesame plants, and this should be maintained at least until the ninth week to avoid sesame yield losses by more than 5%. These findings show that growers can benefit from CPWC to improve weed control in sesame production, including the efficacy of a weed control program and its cost.
{"title":"Critical period for weed control in sesame production","authors":"Z. Karnas, D. Işık, N. Tursun, K. Jabran","doi":"10.1111/wbm.12188","DOIUrl":"https://doi.org/10.1111/wbm.12188","url":null,"abstract":"Planning effective weed control in cropping systems requires exact appraisal of the weed intensity and duration of their competition with the crops. This 2‐year study was carried out in order to determine the critical weed control period in sesame fields. Related and relative crop yields were monitored and analyzed using a four‐parametric log‐logistic model. We recorded data from weed‐free plots and compared these with data from different periods of weed interference. In both the study years, the longer period of weed interference decreased the relative yield of sesame, whereas the yield was increased with increasing duration of the weed‐free period. A 51–78.7% decline in sesame yield was noted if the weeds were allowed to compete with the crop from planting to harvest. In the first year, the duration of the critical period for weed control (CPWC) was 177–820 growing degree days (GDD), which corresponded to 14–64 days after crop emergence (DAE), and between 170 and 837 GDD (13–64 DAE) in the second year; this was based on a 5% acceptable yield loss. The results of this study clearly elaborated that maintaining weed‐free conditions is compulsory from as early as the second week after the emergence of sesame plants, and this should be maintained at least until the ninth week to avoid sesame yield losses by more than 5%. These findings show that growers can benefit from CPWC to improve weed control in sesame production, including the efficacy of a weed control program and its cost.","PeriodicalId":23536,"journal":{"name":"Weed Biology and Management","volume":"19 1","pages":"121-128"},"PeriodicalIF":1.4,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/wbm.12188","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44985452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. T. Forte, U. R. Nunes, A. C. Filho, L. Galon, Leonardo Chechi, R. Roso, André Dalponte Menegat, E. Rossetto, Milena Barretta Franceschetti
Solanum americanum Mill. is a weed that occurs with a number of crops, and it is known for its high seed production and its staggered germination. The objective of this work was to evaluate the germination behavior of S. americanum seeds under the influence of chemical and environmental factors. In the laboratory, we tested the effect on germination of (i) constant and alternating temperatures, (ii) seed washing, (iii) exposure time and concentration of chemical treatments and (iv) seeding depth and soil covered with plant residue on seedling emergence. The variables analyzed were germination percentage, germination rate index, seedling emergence and length of the seedlings. The results indicated that alternating temperatures are the main way to promote germination of S. americanum; however, chemical treatments can help to increase the germination percentage and rate index. There was no increase in germination with seed washing, with the exception of KNO₃ application. A GA₃ concentration of 0.84 g L⁻¹ and an exposure time of 21.22 h in 0.2% of KNO₃ promoted the highest germination of S. americanum. Germination occurs when seeds remain on the soil surface and are not covered by crop residue.
美洲龙葵是一种与许多作物一起生长的杂草，以其高种子产量和交错发芽而闻名。本研究的目的是评价化学和环境因素对美洲藜种子萌发行为的影响。在实验室中，我们测试了(i)恒定温度和交替温度对发芽的影响，(ii)种子清洗，(iii)化学处理的暴露时间和浓度，(iv)播种深度和覆盖植物残留物的土壤对幼苗出苗的影响。分析的变量包括发芽率、发芽率指数、出苗率和幼苗长度。结果表明，交变温度是促进美洲葡萄发芽的主要途径;而化学处理能提高发芽率和发芽率指数。除了使用KNO₃外，洗籽没有增加发芽率。在0.2%的KNO₃中，GA₃的浓度为0.84 g L⁻¹，暴露时间为21.22 h，促进了美洲葡萄的最高发芽率。当种子停留在土壤表面而没有被作物残留物覆盖时，萌发就发生了。
{"title":"Chemical and environmental factors driving germination of\u0000 Solanum americanum\u0000 seeds","authors":"C. T. Forte, U. R. Nunes, A. C. Filho, L. Galon, Leonardo Chechi, R. Roso, André Dalponte Menegat, E. Rossetto, Milena Barretta Franceschetti","doi":"10.1111/wbm.12187","DOIUrl":"https://doi.org/10.1111/wbm.12187","url":null,"abstract":"Solanum americanum Mill. is a weed that occurs with a number of crops, and it is known for its high seed production and its staggered germination. The objective of this work was to evaluate the germination behavior of S. americanum seeds under the influence of chemical and environmental factors. In the laboratory, we tested the effect on germination of (i) constant and alternating temperatures, (ii) seed washing, (iii) exposure time and concentration of chemical treatments and (iv) seeding depth and soil covered with plant residue on seedling emergence. The variables analyzed were germination percentage, germination rate index, seedling emergence and length of the seedlings. The results indicated that alternating temperatures are the main way to promote germination of S. americanum; however, chemical treatments can help to increase the germination percentage and rate index. There was no increase in germination with seed washing, with the exception of KNO₃ application. A GA₃ concentration of 0.84 g L⁻¹ and an exposure time of 21.22 h in 0.2% of KNO₃ promoted the highest germination of S. americanum. Germination occurs when seeds remain on the soil surface and are not covered by crop residue.","PeriodicalId":23536,"journal":{"name":"Weed Biology and Management","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/wbm.12187","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42777419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herbicides applied alone have failed to reduce weed populations in agricultural ecosystems. The use of this management strategy has followed other problems such as damage to ecosystems and organisms that live in it. Herbicide resistance in weeds has also occurred more quickly based on the application of herbicides. Today, most scientists are looking for new integrated weed management programs in agricultural ecosystems. Biological control is one of the most effective ways of weed management. In this way, living organisms are used to reduce and control weed species in arable lands. Weed seed predators, including predispersal and postdispersal predators as biological control agents, can be primary factors of weed seed mortality in agricultural ecosystems. This review has discussed factors influencing seed predator populations, activity, and granivory. Knowledge of the interrelations between factors and seed predators can contribute to designing future strategies that augment weed seed predator activity and enhance weed seed consumption as a component of an integrated weed management system.
{"title":"Factors that influence the level of weed seed predation: A review","authors":"V. Sarabi","doi":"10.1111/wbm.12186","DOIUrl":"https://doi.org/10.1111/wbm.12186","url":null,"abstract":"Herbicides applied alone have failed to reduce weed populations in agricultural ecosystems. The use of this management strategy has followed other problems such as damage to ecosystems and organisms that live in it. Herbicide resistance in weeds has also occurred more quickly based on the application of herbicides. Today, most scientists are looking for new integrated weed management programs in agricultural ecosystems. Biological control is one of the most effective ways of weed management. In this way, living organisms are used to reduce and control weed species in arable lands. Weed seed predators, including predispersal and postdispersal predators as biological control agents, can be primary factors of weed seed mortality in agricultural ecosystems. This review has discussed factors influencing seed predator populations, activity, and granivory. Knowledge of the interrelations between factors and seed predators can contribute to designing future strategies that augment weed seed predator activity and enhance weed seed consumption as a component of an integrated weed management system.","PeriodicalId":23536,"journal":{"name":"Weed Biology and Management","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/wbm.12186","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41497466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Kurokawa, A. Kaga, Mai Tsuda, Daisuke Sekine, T. Shibuya
{"title":"Evaluation of validity and limitations of the soybean canopy height‐to‐row spacing ratio as an onsite index to control weeds using diverse soybean accessions","authors":"S. Kurokawa, A. Kaga, Mai Tsuda, Daisuke Sekine, T. Shibuya","doi":"10.1111/wbm.12184","DOIUrl":"https://doi.org/10.1111/wbm.12184","url":null,"abstract":"","PeriodicalId":23536,"journal":{"name":"Weed Biology and Management","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/wbm.12184","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46723316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Echinochloa crus‐galli (L.) Beauv. var. formosensis Ohwi (2n = 6x = 54, AABBCC genomes) and Echinochloa oryzicola (Vasinger) Vasinger (2n = 4x = 36, AABB) are major paddy weeds in East and Southeast Asia. E. oryzicola has been generally considered to be a paternal genome donor of E. crus‐galli s. l., which includes E. crus‐galli var. formosensis based on cpDNA sequences. Thus, molecular characterization using polymerase chain reaction‐restriction fragment length polymorphism analysis of cpDNA has been proposed as a reliable method for discriminating between the two species. In this study, we report that four accessions of E. crus‐galli var. formosensis from Okinawa, Nagasaki, Shizuoka and Tokyo had similar cpDNA sequences to E. oryzicola and had been misidentified as E. oryzicola using molecular methods. In addition, our results demonstrated that these accessions likely inherited their chloroplast genomes from E. oryzicola and not from an anonymous diploid species during polyploidization. Our findings provide new insights into the evolution of E. crus‐galli s. l. and suggest that identification using the cpDNA molecular method alone is not an appropriate approach to differentiate E. crus‐galli var. formosensis and E. oryzicola.
{"title":"Misidentifications of\u0000 Echinochloa crus‐galli\u0000 var.\u0000 formosensis\u0000 as\u0000 Echinochloa oryzicola\u0000 as a result of similar cpDNA sequences","authors":"K. Yasuda, Y. Nakayama","doi":"10.1111/WBM.12185","DOIUrl":"https://doi.org/10.1111/WBM.12185","url":null,"abstract":"Echinochloa crus‐galli (L.) Beauv. var. formosensis Ohwi (2n = 6x = 54, AABBCC genomes) and Echinochloa oryzicola (Vasinger) Vasinger (2n = 4x = 36, AABB) are major paddy weeds in East and Southeast Asia. E. oryzicola has been generally considered to be a paternal genome donor of E. crus‐galli s. l., which includes E. crus‐galli var. formosensis based on cpDNA sequences. Thus, molecular characterization using polymerase chain reaction‐restriction fragment length polymorphism analysis of cpDNA has been proposed as a reliable method for discriminating between the two species. In this study, we report that four accessions of E. crus‐galli var. formosensis from Okinawa, Nagasaki, Shizuoka and Tokyo had similar cpDNA sequences to E. oryzicola and had been misidentified as E. oryzicola using molecular methods. In addition, our results demonstrated that these accessions likely inherited their chloroplast genomes from E. oryzicola and not from an anonymous diploid species during polyploidization. Our findings provide new insights into the evolution of E. crus‐galli s. l. and suggest that identification using the cpDNA molecular method alone is not an appropriate approach to differentiate E. crus‐galli var. formosensis and E. oryzicola.","PeriodicalId":23536,"journal":{"name":"Weed Biology and Management","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/WBM.12185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63507045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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