Tatiane Severo Silva, Nicholas John Arneson, Daniel Valadão Silva, Rodrigo Werle
Abstract More growers across the US Midwest are considering interseeding or overseeding cover crops into corn for soil health purposes. One challenge of this practice is the potential injury from soil residual herbicides applied preemergence (PRE) for weed control in corn to the interseeded and overseeded cover crop species. Field treated soil was collected in 2021 and 2022 at Janesville and Lancaster, WI to investigate the impact of PRE residual herbicides on establishment of interseeded and overseeded cover crops via greenhouse bioassay. Soil samples (0-5 cm depth) were collected from field experiments at 0, 10, 20, 30, 40, 50, 60, and 70 days after treatment (DAT). Treatments consisted of 14 single and multiple sites of action PRE herbicides plus a nontreated check (NTC). Four bioindicator cover crop species were used in the greenhouse bioassay: annual ryegrass, cereal rye, radish, and red clover. Cover crop biomass was collected 28 days after bioassay seeding. Cover crop species responded differently across herbicide treatments. Annual ryegrass and cereal rye were sensitive to treatments containing herbicide group 15, whereas groups 2, 4, 5, 14, and 27 had minimal impact on their establishment when field soil was collected at 30 DAT (interseeding scenario) and 70 DAT (overseeding scenario) compared to the NTC. Radish and red clover were sensitive to herbicide groups 2, 4, and 27, whereas groups 5, 14, and 15 had minimal impact on their establishment. Annual ryegrass, radish, and red clover were more sensitive to PRE herbicides containing two and three sites of action than herbicides with a single site of action. Based on these greenhouse bioassay results, cover crop species should be carefully selected depending on the soil residual herbicide when interseeded and overseeded into corn. Field studies will be conducted to validate these results and support recommendations to growers interested in this system.
{"title":"Evaluating cover crop tolerance to corn residual herbicides using field treated soil in greenhouse bioassay","authors":"Tatiane Severo Silva, Nicholas John Arneson, Daniel Valadão Silva, Rodrigo Werle","doi":"10.1017/wet.2023.72","DOIUrl":"https://doi.org/10.1017/wet.2023.72","url":null,"abstract":"Abstract More growers across the US Midwest are considering interseeding or overseeding cover crops into corn for soil health purposes. One challenge of this practice is the potential injury from soil residual herbicides applied preemergence (PRE) for weed control in corn to the interseeded and overseeded cover crop species. Field treated soil was collected in 2021 and 2022 at Janesville and Lancaster, WI to investigate the impact of PRE residual herbicides on establishment of interseeded and overseeded cover crops via greenhouse bioassay. Soil samples (0-5 cm depth) were collected from field experiments at 0, 10, 20, 30, 40, 50, 60, and 70 days after treatment (DAT). Treatments consisted of 14 single and multiple sites of action PRE herbicides plus a nontreated check (NTC). Four bioindicator cover crop species were used in the greenhouse bioassay: annual ryegrass, cereal rye, radish, and red clover. Cover crop biomass was collected 28 days after bioassay seeding. Cover crop species responded differently across herbicide treatments. Annual ryegrass and cereal rye were sensitive to treatments containing herbicide group 15, whereas groups 2, 4, 5, 14, and 27 had minimal impact on their establishment when field soil was collected at 30 DAT (interseeding scenario) and 70 DAT (overseeding scenario) compared to the NTC. Radish and red clover were sensitive to herbicide groups 2, 4, and 27, whereas groups 5, 14, and 15 had minimal impact on their establishment. Annual ryegrass, radish, and red clover were more sensitive to PRE herbicides containing two and three sites of action than herbicides with a single site of action. Based on these greenhouse bioassay results, cover crop species should be carefully selected depending on the soil residual herbicide when interseeded and overseeded into corn. Field studies will be conducted to validate these results and support recommendations to growers interested in this system.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135923632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Erica D. Shoenberger, Jacob M. Jungers, Eugene P. Law, Clair L. Keene, Antonio DiTommaso, Craig C. Sheaffer, Donald L. Wyse, Valentin D. Picasso, David E. Stoltenberg
Abstract Intermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019-2021) at sites in Wisconsin, Minnesota, New York, and North Dakota, USA. This evaluation included Group 4 broadleaf herbicides registered in wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA. Each herbicide or mixture was applied at 1X and 2X the labeled wheat application rate to newly planted and established (1 to 5 yr old) IWG stands in the fall or spring. Applications were made during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71 to 92% across herbicide treatments relative to the nontreated check at the WI site while weed control at the MN site was variable among treatments. At the NY site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the ND site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.
{"title":"Synthetic auxin herbicides do not injure intermediate wheatgrass or affect grain yield","authors":"Erica D. Shoenberger, Jacob M. Jungers, Eugene P. Law, Clair L. Keene, Antonio DiTommaso, Craig C. Sheaffer, Donald L. Wyse, Valentin D. Picasso, David E. Stoltenberg","doi":"10.1017/wet.2023.71","DOIUrl":"https://doi.org/10.1017/wet.2023.71","url":null,"abstract":"Abstract Intermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019-2021) at sites in Wisconsin, Minnesota, New York, and North Dakota, USA. This evaluation included Group 4 broadleaf herbicides registered in wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA. Each herbicide or mixture was applied at 1X and 2X the labeled wheat application rate to newly planted and established (1 to 5 yr old) IWG stands in the fall or spring. Applications were made during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71 to 92% across herbicide treatments relative to the nontreated check at the WI site while weed control at the MN site was variable among treatments. At the NY site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the ND site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135548652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daljit Singh, Andrew Tyre, Alejandro Perez-Jones, Jenny Krebel, John Willis, Jeffrey Herrmann, Tracy Klingaman, Graham Head, Chandrashekar Aradhya
Abstract Herbicide resistance in Palmer amaranth and waterhemp is on the rise and poses a great concern to growers in the United States. A multistate screening was conducted for these two weed species in the United States to assess their sensitivity to glufosinate, dicamba, and 2,4-D. The screening was designed to understand the weed sensitivity landscape and emerging trends in resistance evolution by testing each herbicide at its respective label rate and at half the label rate. A total of 303 weed seed accessions from 21 states representing 162 Palmer amaranth and 141 waterhemp seeds were collected from grower fields in 2019 and screened in greenhouse conditions. Statistical power of different sample sizes and probability of survivors in each accession were estimated for each species and herbicide treatment. Overall, the efficacy of glufosinate, dicamba, and 2,4-D against all these accessions was excellent, with greater than 90% average injury. The variability in herbicide injury, if any, was greater with half the label rate of 2,4-D in some Palmer amaranth accessions, while waterhemp accessions had exhibited variable sensitivity with half the label rate of dicamba and glufosinate. The study highlights the value of monitoring weeds for herbicide sensitivity across broader landscape and the importance of glufosinate, dicamba, and 2,4-D herbicides in managing troublesome weeds as part of a diversified weed control program integrated with other chemical, mechanical and cultural practices.
{"title":"Multi-State Screening of Palmer Amaranth (<i>Amaranthus palmeri</i>) and Waterhemp (<i>Amaranthus tuberculatus</i>) Sensitivity to Glufosinate, Dicamba and 2,4-D in the United States","authors":"Daljit Singh, Andrew Tyre, Alejandro Perez-Jones, Jenny Krebel, John Willis, Jeffrey Herrmann, Tracy Klingaman, Graham Head, Chandrashekar Aradhya","doi":"10.1017/wet.2023.69","DOIUrl":"https://doi.org/10.1017/wet.2023.69","url":null,"abstract":"Abstract Herbicide resistance in Palmer amaranth and waterhemp is on the rise and poses a great concern to growers in the United States. A multistate screening was conducted for these two weed species in the United States to assess their sensitivity to glufosinate, dicamba, and 2,4-D. The screening was designed to understand the weed sensitivity landscape and emerging trends in resistance evolution by testing each herbicide at its respective label rate and at half the label rate. A total of 303 weed seed accessions from 21 states representing 162 Palmer amaranth and 141 waterhemp seeds were collected from grower fields in 2019 and screened in greenhouse conditions. Statistical power of different sample sizes and probability of survivors in each accession were estimated for each species and herbicide treatment. Overall, the efficacy of glufosinate, dicamba, and 2,4-D against all these accessions was excellent, with greater than 90% average injury. The variability in herbicide injury, if any, was greater with half the label rate of 2,4-D in some Palmer amaranth accessions, while waterhemp accessions had exhibited variable sensitivity with half the label rate of dicamba and glufosinate. The study highlights the value of monitoring weeds for herbicide sensitivity across broader landscape and the importance of glufosinate, dicamba, and 2,4-D herbicides in managing troublesome weeds as part of a diversified weed control program integrated with other chemical, mechanical and cultural practices.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135198959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zachary S. Howard, Scott A. Nolte, Mark Hussey, Morgan L. Treadwell, Brent Sellers
Abstract Smutgrass is a non-native perennial weed that is problematic because of its poor palatability to cattle and its difficulty to control once established. Limited literature exists to explain the effectiveness of herbicides other than hexazinone for smutgrass control and forage injury. This study aimed to evaluate seasonal applications of labeled herbicides used on forage for maximum smutgrass control. The second objective was to evaluate preemergent herbicides and hexazinone for their ability to control smutgrass germinating from seed. Hexazinone, nicosulfuron + metsulfuron-methyl, and glyphosate + imazapic were the most effective postemergence treatments, while quinclorac exhibited little activity on smutgrass. Common bermudagrass forage fully recovered from all treatments by 3 mo after treatment. Hexazinone, nicosulfuron + metsulfuron methyl, glyphosate, and imazapic were applied postemergence to smutgrass in spring, summer, and fall. Summer applications of hexazinone resulted in the greatest level of control, while spring treatments provided the least control. Applications of hexazinone or glyphosate resulted in the most effective smutgrass control. However, fall applications resulted in the least forage injury. Results of the study of preemergence herbicides indicate that treatments with indaziflam and hexazinone provide adequate control of germinating smutgrass seedlings in the greenhouse at 0.25×, 0.5×, and 0.75× of the lowest recommended labeled rate for seedling grass control. Indaziflam treatments prevented the emergence of any visible smutgrass seedling tissue, compared to hexazinone, which fully controlled the germinating seedlings by 21 d after treatment, whereas pendimethalin significantly reduced seedling numbers at the 0.5× and 0.75× rates.
{"title":"Evaluation of Chemical Control and Seasonal Application Options for Smutgrass (<i>Sporobolus indicus</i>)","authors":"Zachary S. Howard, Scott A. Nolte, Mark Hussey, Morgan L. Treadwell, Brent Sellers","doi":"10.1017/wet.2023.70","DOIUrl":"https://doi.org/10.1017/wet.2023.70","url":null,"abstract":"Abstract Smutgrass is a non-native perennial weed that is problematic because of its poor palatability to cattle and its difficulty to control once established. Limited literature exists to explain the effectiveness of herbicides other than hexazinone for smutgrass control and forage injury. This study aimed to evaluate seasonal applications of labeled herbicides used on forage for maximum smutgrass control. The second objective was to evaluate preemergent herbicides and hexazinone for their ability to control smutgrass germinating from seed. Hexazinone, nicosulfuron + metsulfuron-methyl, and glyphosate + imazapic were the most effective postemergence treatments, while quinclorac exhibited little activity on smutgrass. Common bermudagrass forage fully recovered from all treatments by 3 mo after treatment. Hexazinone, nicosulfuron + metsulfuron methyl, glyphosate, and imazapic were applied postemergence to smutgrass in spring, summer, and fall. Summer applications of hexazinone resulted in the greatest level of control, while spring treatments provided the least control. Applications of hexazinone or glyphosate resulted in the most effective smutgrass control. However, fall applications resulted in the least forage injury. Results of the study of preemergence herbicides indicate that treatments with indaziflam and hexazinone provide adequate control of germinating smutgrass seedlings in the greenhouse at 0.25×, 0.5×, and 0.75× of the lowest recommended labeled rate for seedling grass control. Indaziflam treatments prevented the emergence of any visible smutgrass seedling tissue, compared to hexazinone, which fully controlled the germinating seedlings by 21 d after treatment, whereas pendimethalin significantly reduced seedling numbers at the 0.5× and 0.75× rates.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135199073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
John M. Peppers, Matthew T. Elmore, Shawn D. Askew
Abstract Few herbicides are registered for goosegrass control in creeping bentgrass turfgrass. Topramezone controls goosegrass and is labeled for use on creeping bentgrass, but potential injury risks lead many turf managers to frequently apply it at a low-dose. This application practice increases the likelihood that topramezone treatments will be mixed with fungicide treatments. Previous research found that fungicides can reduce the activity of some herbicides, but their effects on topramezone efficacy are unknown. Four studies were established between Blacksburg, VA, and North Brunswick, NJ, in 2021 to determine whether chlorothalonil reduces goosegrass control from topramezone. In controlled environment dose-response studies the amount of topramezone needed to reduce goosegrass biomass by 50% increased from 3.04 g ha −1 to 5.27 g ha −1 when chlorothalonil (7,400 g ha −1 ) was added to the mixture. In field experiments, topramezone at 3.7 and 6.1 g ha −1 controlled goosegrass by 50% and 63%, respectively, at 42 d after treatment when averaged across herbicide admixtures. The addition of chlorothalonil alone and chlorothalonil plus acibenzolar-S-methyl to topramezone reduced goosegrass control from 73% to 52% and 45%, respectively, when averaged across topramezone rate. From these studies we can conclude that chlorothalonil has the potential to reduce goosegrass control when topramezone is applied at the maximum allowable rate (6 g ae ha −1 ) or less. This is the first report of fungicides acting to reduce herbicidal weed control efficacy in turfgrass systems.
摘要目前在匍匐生长的弯草类草坪草中，用于防治鹅草的除草剂很少。Topramezone可以控制鹅草，并被标记为用于匍匐的弯曲草，但潜在的伤害风险导致许多草坪管理者经常以低剂量使用它。这一应用实践增加了将topamezone处理与杀菌剂处理混合使用的可能性。以前的研究发现，杀菌剂可以降低某些除草剂的活性，但它们对topamezone功效的影响尚不清楚。2021年，在弗吉尼亚州的布莱克斯堡和新泽西州的北不伦瑞克之间建立了四项研究，以确定百菌清是否会减少topamezone对鹅草的控制。在受控环境剂量反应研究中，当向混合物中添加百菌净(7,400 g ha - 1)时，将鹅草生物量减少50%所需的topamezone的量从3.04 g ha - 1增加到5.27 g ha - 1。在田间试验中，施用3.7和6.1 g ha - 1的topamezone在处理后42 d对鹅草的控制效果分别为50%和63%。单投加百菌清和投加酸苯并- s -甲基百菌清可将鹅毛草的防治率分别从73%降低到52%和45%。从这些研究中，我们可以得出结论，当以最大允许剂量(6 g / h - 1)或更少施用topamezone时，百菌清有可能减少鹅毛草的防治。这是首次报道杀菌剂在草坪草系统中降低除草剂杂草控制效果。
{"title":"Evaluation of goosegrass response to combinations of topramezone and chlorothalonil","authors":"John M. Peppers, Matthew T. Elmore, Shawn D. Askew","doi":"10.1017/wet.2023.67","DOIUrl":"https://doi.org/10.1017/wet.2023.67","url":null,"abstract":"Abstract Few herbicides are registered for goosegrass control in creeping bentgrass turfgrass. Topramezone controls goosegrass and is labeled for use on creeping bentgrass, but potential injury risks lead many turf managers to frequently apply it at a low-dose. This application practice increases the likelihood that topramezone treatments will be mixed with fungicide treatments. Previous research found that fungicides can reduce the activity of some herbicides, but their effects on topramezone efficacy are unknown. Four studies were established between Blacksburg, VA, and North Brunswick, NJ, in 2021 to determine whether chlorothalonil reduces goosegrass control from topramezone. In controlled environment dose-response studies the amount of topramezone needed to reduce goosegrass biomass by 50% increased from 3.04 g ha −1 to 5.27 g ha −1 when chlorothalonil (7,400 g ha −1 ) was added to the mixture. In field experiments, topramezone at 3.7 and 6.1 g ha −1 controlled goosegrass by 50% and 63%, respectively, at 42 d after treatment when averaged across herbicide admixtures. The addition of chlorothalonil alone and chlorothalonil plus acibenzolar-S-methyl to topramezone reduced goosegrass control from 73% to 52% and 45%, respectively, when averaged across topramezone rate. From these studies we can conclude that chlorothalonil has the potential to reduce goosegrass control when topramezone is applied at the maximum allowable rate (6 g ae ha −1 ) or less. This is the first report of fungicides acting to reduce herbicidal weed control efficacy in turfgrass systems.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135770475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
George B. Frisvold, Chandrakant Agme, David Ervin, Jennifer Allen, Shawn Askew, Rebecca Grubbs Bowling, Jim Brosnan, Matt Elmore, Travis Gannon, John Kaminski, Lambert McCarty, James D. McCurdy, Aaron J. Patton, Jacob Taylor, J. Bryan Unruh, Muthukumar Bagavathiannan
Abstract Data from a national survey of 348 U.S. sports field managers were used to examine the effects of participation in Cooperative Extension events on the adoption of turfgrass weed management practices. Of the respondents, 94% attended at least one event in the previous three years. Of this 94%, 97% reported adopting at least one practice as a result of knowledge gained at an Extension turfgrass event. Half of the respondents adopted four or more practices; a third adopted five or more practices. Non-chemical, cultural practices were the most-adopted practices (65% of respondents). Multiple regression analysis was used to examine factors explaining practice adoption and Extension event attendance. Compared to attending one event, attending three events increased total adoption by an average of one practice. Attending four or more events increased total adoption by two practices. Attending four or more events (compared to one event) increased the odds of adopting six individual practices by 3- to 6-fold, depending on the practice. This suggests practice adoption could be enhanced by encouraging repeat attendance among past Extension event attendees. Manager experience was a statistically significant predictor of the number of Extension events attended, but a poor direct predictor of practice adoption. Experience does not appear to increase adoption directly, but indirectly, via its impact on Extension event attendance. In addition to questions about weed management generally, the survey asked questions about annual bluegrass management, specifically. Respondents were asked to rank seven sources of information for their helpfulness in managing annual bluegrass. There was no single dominant information source, but Extension was ranked as the most helpful more than any other source (by 22% of the respondents) and was ranked among the top three by 53%, closely behind field representative/local distributor sources at 54%.
{"title":"Extension event attendance increases adoption of weed management practices by sports field managers","authors":"George B. Frisvold, Chandrakant Agme, David Ervin, Jennifer Allen, Shawn Askew, Rebecca Grubbs Bowling, Jim Brosnan, Matt Elmore, Travis Gannon, John Kaminski, Lambert McCarty, James D. McCurdy, Aaron J. Patton, Jacob Taylor, J. Bryan Unruh, Muthukumar Bagavathiannan","doi":"10.1017/wet.2023.66","DOIUrl":"https://doi.org/10.1017/wet.2023.66","url":null,"abstract":"Abstract Data from a national survey of 348 U.S. sports field managers were used to examine the effects of participation in Cooperative Extension events on the adoption of turfgrass weed management practices. Of the respondents, 94% attended at least one event in the previous three years. Of this 94%, 97% reported adopting at least one practice as a result of knowledge gained at an Extension turfgrass event. Half of the respondents adopted four or more practices; a third adopted five or more practices. Non-chemical, cultural practices were the most-adopted practices (65% of respondents). Multiple regression analysis was used to examine factors explaining practice adoption and Extension event attendance. Compared to attending one event, attending three events increased total adoption by an average of one practice. Attending four or more events increased total adoption by two practices. Attending four or more events (compared to one event) increased the odds of adopting six individual practices by 3- to 6-fold, depending on the practice. This suggests practice adoption could be enhanced by encouraging repeat attendance among past Extension event attendees. Manager experience was a statistically significant predictor of the number of Extension events attended, but a poor direct predictor of practice adoption. Experience does not appear to increase adoption directly, but indirectly, via its impact on Extension event attendance. In addition to questions about weed management generally, the survey asked questions about annual bluegrass management, specifically. Respondents were asked to rank seven sources of information for their helpfulness in managing annual bluegrass. There was no single dominant information source, but Extension was ranked as the most helpful more than any other source (by 22% of the respondents) and was ranked among the top three by 53%, closely behind field representative/local distributor sources at 54%.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"174 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136309074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Delaney C Foster, Peter A Dotray, Stanley Culpepper, Lawrence E Steckel
Abstract Cotton and soybean growers were offered new technologies in 2016, expanding in-crop herbicide options to include dicamba or 2,4-D. Within three years of commercialization, dicamba use in these crops increased ten-fold and growers began to report Palmer amaranth escapes in dicamba-tolerant production systems in western Tennessee. In 2020, Palmer amaranth seed was collected from eight Tennessee locations where growers witnessed poor control following dicamba. Greenhouse experiments were conducted to evaluate the response of these Palmer amaranth populations to dicamba. In 2021, field experiments were conducted on two tentative dicamba-susceptible populations in Georgia, on three confirmed dicamba-resistant populations in Tennessee, and on a tentative dicamba-susceptible population in Texas to evaluate cotton response following dicamba and to examine if malathion insecticide (a cytochrome P450 inhibitor) would improve weed control and not reduce cotton yield when applied in conjunction with dicamba. Palmer amaranth populations collected in 2020 survived dicamba in the greenhouse at 1, 2, and 4 times the labeled rate. There was 15 to 26% survival exhibited by five Palmer amaranth populations to the labeled dicamba rate (560 g ha -1 ) in the greenhouse. These findings were reinforced in the field when research on three of those populations in 2021 showed 55% control with the labeled dicamba rate and 69% control with 2 times the labeled rate. This demonstrates the dicamba resistance allele or alleles were passed between generations. This result was not consistent in the Macon County or Worth County, GA locations where malathion improved dicamba control of 15- to 38-cm tall Palmer amaranth. Cotton injury was observed when malathion was applied in combination with dicamba. These results further document the evolution of dicamba-resistant Palmer amaranth in Tennessee. Moreover, the non-reversal of resistance phenotype by malathion may suggest that the resistance mechanism is something other than metabolism.
2016年，棉花和大豆种植者获得了新技术，增加了麦草畏或2,4- d除草剂的选择。在商业化的三年内，麦草畏在这些作物中的使用增加了十倍，种植者开始报告在田纳西州西部耐麦草畏的生产系统中，帕尔默苋菜逃逸。2020年，从田纳西州的八个地方收集了帕尔默苋菜种子，种植者发现麦草畏后控制不佳。通过温室试验评价了这些苋菜群体对麦草畏的反应。2021年，对佐治亚州的两个麦草畏试探性易感种群、田纳西州的三个麦草畏抗性种群和德克萨斯州的一个麦草畏试探性易感种群进行了田间试验，以评估麦草畏对棉花的反应，并检验马拉硫磷杀虫剂(一种细胞色素P450抑制剂)与麦草畏联合使用是否会改善杂草控制，而不会降低棉花产量。2020年收集的苋菜种群在温室中麦草畏的存活率分别是标记率的1倍、2倍和4倍。在温室中，5个苋菜群体对标记的麦草畏用量(560 g ha -1)的存活率为15% ~ 26%。这些发现在2021年对其中三个种群的研究中得到了进一步的证实，55%的种群控制了标记的麦草畏含量，69%的种群控制了标记的麦草畏含量的两倍。这表明抗麦草畏等位基因或等位基因在代间传递。在乔治亚州的梅肯县或沃斯县，马拉硫磷改善了对15至38厘米高的帕尔默苋菜的麦草畏控制，但这一结果并不一致。马拉硫磷与麦草畏联用对棉花有伤害。这些结果进一步证明了田纳西州抗麦草畏苋菜的进化。此外，马拉硫磷对抗性表型的不逆转可能表明抗性机制不是代谢机制。
{"title":"Response of Dicamba-Resistant Palmer amaranth and Cotton to Malathion Applied in Conjunction with Dicamba","authors":"Delaney C Foster, Peter A Dotray, Stanley Culpepper, Lawrence E Steckel","doi":"10.1017/wet.2023.62","DOIUrl":"https://doi.org/10.1017/wet.2023.62","url":null,"abstract":"Abstract Cotton and soybean growers were offered new technologies in 2016, expanding in-crop herbicide options to include dicamba or 2,4-D. Within three years of commercialization, dicamba use in these crops increased ten-fold and growers began to report Palmer amaranth escapes in dicamba-tolerant production systems in western Tennessee. In 2020, Palmer amaranth seed was collected from eight Tennessee locations where growers witnessed poor control following dicamba. Greenhouse experiments were conducted to evaluate the response of these Palmer amaranth populations to dicamba. In 2021, field experiments were conducted on two tentative dicamba-susceptible populations in Georgia, on three confirmed dicamba-resistant populations in Tennessee, and on a tentative dicamba-susceptible population in Texas to evaluate cotton response following dicamba and to examine if malathion insecticide (a cytochrome P450 inhibitor) would improve weed control and not reduce cotton yield when applied in conjunction with dicamba. Palmer amaranth populations collected in 2020 survived dicamba in the greenhouse at 1, 2, and 4 times the labeled rate. There was 15 to 26% survival exhibited by five Palmer amaranth populations to the labeled dicamba rate (560 g ha -1 ) in the greenhouse. These findings were reinforced in the field when research on three of those populations in 2021 showed 55% control with the labeled dicamba rate and 69% control with 2 times the labeled rate. This demonstrates the dicamba resistance allele or alleles were passed between generations. This result was not consistent in the Macon County or Worth County, GA locations where malathion improved dicamba control of 15- to 38-cm tall Palmer amaranth. Cotton injury was observed when malathion was applied in combination with dicamba. These results further document the evolution of dicamba-resistant Palmer amaranth in Tennessee. Moreover, the non-reversal of resistance phenotype by malathion may suggest that the resistance mechanism is something other than metabolism.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135435590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laura Anderson, Scott Neil White, Andrew McKenzie-Gopsill
Potato producers in Canada’s Atlantic provinces of Prince Edward Island (PE) and New Brunswick (NB) rely on photosystem II (PSII)-inhibiting herbicides to provide season-long weed control. Despite this fact, a high proportion of common lambsquarters populations in the region have been identified as resistant to this class of herbicides. Crop-topping is a late-season weed management practice that exploits the height differential between weeds and a developing crop canopy. Two field experiments were conducted in Harrington, PE, in 2020 and 2021 one each to evaluate the efficacy of a different crop-topping strategy, above-canopy mowing or wick-applied glyphosate, at two potato phenological stages, on common lambsquarters viable seed production and potato yield and quality. Mowing common lambsquarters post-flowering decreased viable seed production (72%-91%) in 2020 but increased seed production (78%-278%) in 2021. Mowing had minimal impact on potato marketable yield across cultivars in both years. In contrast, treating common lambsquarters with wick-applied glyphosate had variable impacts on seed output in 2020 but dramatically reduced seed production (up to 95%) in 2021 when treatments were applied pre-flowering. Glyphosate damage to potato tubers was not influenced by timing and resulted in a 14%-15% increase in culled tubers due to black spotting and rot. Our results highlight the importance of potato and common lambsquarters phenology when selecting a crop-topping strategy and demonstrate that above-canopy mowing and wick-applied glyphosate can be utilized for seedbank management of herbicide resistant common lambsquarters in potato production systems.
{"title":"Evaluation of crop-topping strategies to reduce common lambsquarters (Chenopodium album) seed production in potato production systems","authors":"Laura Anderson, Scott Neil White, Andrew McKenzie-Gopsill","doi":"10.1017/wet.2023.61","DOIUrl":"https://doi.org/10.1017/wet.2023.61","url":null,"abstract":"\u0000 Potato producers in Canada’s Atlantic provinces of Prince Edward Island (PE) and New Brunswick (NB) rely on photosystem II (PSII)-inhibiting herbicides to provide season-long weed control. Despite this fact, a high proportion of common lambsquarters populations in the region have been identified as resistant to this class of herbicides. Crop-topping is a late-season weed management practice that exploits the height differential between weeds and a developing crop canopy. Two field experiments were conducted in Harrington, PE, in 2020 and 2021 one each to evaluate the efficacy of a different crop-topping strategy, above-canopy mowing or wick-applied glyphosate, at two potato phenological stages, on common lambsquarters viable seed production and potato yield and quality. Mowing common lambsquarters post-flowering decreased viable seed production (72%-91%) in 2020 but increased seed production (78%-278%) in 2021. Mowing had minimal impact on potato marketable yield across cultivars in both years. In contrast, treating common lambsquarters with wick-applied glyphosate had variable impacts on seed output in 2020 but dramatically reduced seed production (up to 95%) in 2021 when treatments were applied pre-flowering. Glyphosate damage to potato tubers was not influenced by timing and resulted in a 14%-15% increase in culled tubers due to black spotting and rot. Our results highlight the importance of potato and common lambsquarters phenology when selecting a crop-topping strategy and demonstrate that above-canopy mowing and wick-applied glyphosate can be utilized for seedbank management of herbicide resistant common lambsquarters in potato production systems.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42869156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Six field experiments were established in southwestern Ontario in 2021 and 2022 to evaluate if the addition of a grass herbicide (acetochlor, dimethenamid-p, flufenacet, pendimethalin, pyroxasulfone, or S-metolachlor) to tolpyralate + atrazine improves late-season weed control in corn. Tolpyralate + atrazine caused 12% and 5% corn injury at 1 and 4 weeks after herbicide application (WAA); corn injury was not increased with the addition of a grass herbicide. Weed inference reduced corn yield 60%. The addition of a grass herbicide to tolpyralate + atrazine did not enhance velvetleaf control. The addition of acetochlor or dimethenamid-p to tolpyralate + atrazine enhanced pigweed species control 4% 4 WAA; the addition of other grass herbicides tested did not increase pigweed species control. The addition of acetochlor enhanced common ragweed control 5% at 4 WAA and the addition of acetochlor or dimethenamid-p enhanced common ragweed control 8% at 8 WAA; the addition of other grass herbicides did not improve common ragweed control. The addition of acetochlor to tolpyralate + atrazine enhanced common lambsquarters control up to 4%; there was no enhancement in common lambsquarters control with the addition of the other grass herbicides. Tolpyralate + atrazine controlled barnyardgrass 90% and 78% at 4 and 8 WAA, respectively; the addition of a grass herbicide enhanced barnyardgrass control 9 to 10% and 21% at 4 and 8 WAA, respectively. Tolpyralate + atrazine controlled green or giant foxtail 80% and 69% at 4 and 8 WAA, respectively; the addition of a grass herbicide enhanced foxtail species control 15 to 19% and 24 to 29% at 4 and 8 WAA, respectively. This research shows that adding a grass herbicide to tolpyralate + atrazine mixture can improve weed control efficacy, especially increased annual grass control in corn production.
{"title":"Weed control in corn with tolpyralate and atrazine plus grass herbicides","authors":"N. Soltani, C. Shropshire, P. Sikkema","doi":"10.1017/wet.2023.63","DOIUrl":"https://doi.org/10.1017/wet.2023.63","url":null,"abstract":"\u0000 Six field experiments were established in southwestern Ontario in 2021 and 2022 to evaluate if the addition of a grass herbicide (acetochlor, dimethenamid-p, flufenacet, pendimethalin, pyroxasulfone, or S-metolachlor) to tolpyralate + atrazine improves late-season weed control in corn. Tolpyralate + atrazine caused 12% and 5% corn injury at 1 and 4 weeks after herbicide application (WAA); corn injury was not increased with the addition of a grass herbicide. Weed inference reduced corn yield 60%. The addition of a grass herbicide to tolpyralate + atrazine did not enhance velvetleaf control. The addition of acetochlor or dimethenamid-p to tolpyralate + atrazine enhanced pigweed species control 4% 4 WAA; the addition of other grass herbicides tested did not increase pigweed species control. The addition of acetochlor enhanced common ragweed control 5% at 4 WAA and the addition of acetochlor or dimethenamid-p enhanced common ragweed control 8% at 8 WAA; the addition of other grass herbicides did not improve common ragweed control. The addition of acetochlor to tolpyralate + atrazine enhanced common lambsquarters control up to 4%; there was no enhancement in common lambsquarters control with the addition of the other grass herbicides. Tolpyralate + atrazine controlled barnyardgrass 90% and 78% at 4 and 8 WAA, respectively; the addition of a grass herbicide enhanced barnyardgrass control 9 to 10% and 21% at 4 and 8 WAA, respectively. Tolpyralate + atrazine controlled green or giant foxtail 80% and 69% at 4 and 8 WAA, respectively; the addition of a grass herbicide enhanced foxtail species control 15 to 19% and 24 to 29% at 4 and 8 WAA, respectively. This research shows that adding a grass herbicide to tolpyralate + atrazine mixture can improve weed control efficacy, especially increased annual grass control in corn production.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45389883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：