Weed Technology最新文献

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"title":"Effect of spray droplet spectra on control of Poa annua with pronamide","authors":"Martin Ignes, J. C. Ferguson, T. Tseng, Barry R. Stewart, E. Castro, J. McCurdy","doi":"10.1017/wet.2023.54","DOIUrl":"https://doi.org/10.1017/wet.2023.54","url":null,"abstract":"\u0000 Annual bluegrass is a troublesome weed in turfgrass, with reported resistance to at least 12 herbicide sites of action. The mitotic-inhibiting herbicide pronamide has both pre- and postemergence activity on susceptible annual bluegrass populations. Previous studies suggest that postemergence activity may be compromised due to lack of root-uptake, as well as target-site- and translocation-based mechanisms. Research was conducted to determine the effects of spray droplet spectra on spray coverage and control of annual bluegrass with pronamide, flazasulfuron, and the mixture of pronamide plus flazasulfuron. Herbicides were delivered to annual bluegrass plants having two to three leaves via five different spray spectra based on volume median diameters (VMD) of 200, 400, 600, 800, and 1000 µm. Fluorescent tracer dye was added to each treatment solution to quantify the effects of herbicide and spray droplet spectra on herbicide deposition. In another experiment, efficacy of 0.58, 1.16, and 2.32 kg pronamide ha-1; 0.022, 0.044, and 0.088 kg flazasulfuron ha-1, or the combination, were assessed in iteration with droplet spectrum sprays of 400 and 1000 µm on two pronamide-resistant and two pronamide-susceptible annual bluegrass populations. Spray droplet spectrum affected deposition of pronamide and flazasulfuron, applied alone and in combination. Pronamide foliar deposition decreased with increasing droplet spectra. Pronamide efficacy was affected by droplet spectrum, with the largest (1000 µm) showing improved control. Flazasulfuron efficacy and pronamide plus flazasulfuron efficacy were not affected by droplet spectra. Pronamide plus flazasulfuron mixture controlled all four populations more effectively than pronamide alone, regardless of droplet spectra. Pronamide plus flazasulfuron mixture applied with relatively large droplets may be optimal for annual bluegrass control, which offers valuable insights for optimizing herbicide application and combatting herbicide resistance. However, applications in this controlled growth pot study may not mimic conditions where thatch and turfgrass canopy limit soil deposition of pronamide.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46722695","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}

{"title":"Assessment of Dicamba and 2,4-D Residues in Palmer amaranth and Soybean","authors":"M. L. Zaccaro-Gruener, J. Norsworthy, L. Piveta, L. Barber, Andy Mauromoustakos","doi":"10.1017/wet.2023.60","DOIUrl":"https://doi.org/10.1017/wet.2023.60","url":null,"abstract":"\u0000 Off-target movement of 2,4-D and dicamba are sometimes to blame as the cause of symptoms observed in weeds growing in production fields. Pesticide regulatory authorities routinely sample tissue of weeds or crops from fields under investigation for potential illegal use of auxin herbicides. This research aimed to determine if analytical tests of herbicide residue on soybean or Palmer amaranth vegetation treated with dicamba or 2,4-D could be used to differentiate between rates applied and how the residue levels decay over a one-month interval. Four rates of each herbicide (1X, 0.1X, 0.01X, and 0.001X) were applied, with a 1X rate of dicamba and 2,4-D assumed to be 560 and 1065 g ae ha-1, respectively. Experiments included dicamba- and 2,4-D-resistant soybean (Xtend and Enlist traits, respectively) and Palmer amaranth categorized by size (8-15 cm, 20-30 cm, and 35-50 cm in height). Analytical results showed that herbicide residues were detected above detection limits of 0.04 µg g-1 for dicamba and 0.004 µg g-1 for 2,4-D, respectively, particularly for samples treated with a 1X and 0.1X rate of dicamba or 2,4-D. Non-detections were frequent, even as early as 2 to 3 days after treatment (DAT), with 0.01X and 0.001X rates of 2,4-D or dicamba. Dicamba residues declined rapidly on Xtend soybean treated with dicamba, and 2,4-D residue in Enlist soybean. The severity of auxin symptomology generally agreed with the ability to detect dicamba or 2,4-D residue in plant tissue for Palmer amaranth, while, for soybean, this was not always the case. Hence, detecting dicamba or 2,4-D residues in both Palmer amaranth and soybean vegetation, along with visible symptoms on both plants during investigations, would generally indicate an earlier direct application of the auxin herbicide rather than off-target movement being the cause of detection.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43872720","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}

{"title":"Russian thistle (Salsola tragus) post-harvest control and plant dispersal","authors":"F. H. Oreja, D. Lyon, Jennifer A. Gourlie, Henry C. Wetzel, Judit Barroso","doi":"10.1017/wet.2023.58","DOIUrl":"https://doi.org/10.1017/wet.2023.58","url":null,"abstract":"\u0000 Russian thistle is one of the most important broadleaf weeds in the semi-arid US Pacific Northwest (PNW). It consumes soil water after wheat harvest, compromising the yield of the following crop. The objectives of this work were to determine the impact of post wheat harvest herbicide application timing on Russian thistle control, and stubble height on Russian thistle post-harvest control and plant dispersal. For the first objective, experiments were conducted at the Columbia Basin Agricultural Research Center (CBARC, Adams, OR) and the Lind Dryland Research Station (LDRS, Lind, WA) in 2020 and 2021. Herbicides evaluated included paraquat, glyphosate, and either bromoxynil + pyrasulfotole (CBARC) or bromoxynil + metribuzin (LDRS). The different post wheat harvest application timings were 24 h, 1, 2, and 3 wk after harvest. For the second objective, two stubble heights (short and tall) were compared for their impact on control at CBARC and in a production field near Ione, OR. Paraquat provided the greatest control in all scenarios, with no differences in application timings or stubble height. Impacts of application timings were not clear for glyphosate or bromoxynil mixtures. For glyphosate treatments, control in short stubble was 11% greater than in tall stubble in both years. Control was also greater in short stubble for the bromoxynil + pyrasulfotole in 2020. However, Russian thistle plant dispersal was greater in short stubble at both locations. At CBARC, plant dispersal in short stubble was 58% compared to 18% in tall stubble. Near Ione, plant dispersal in flattened stubble was 88% compared to 43% in non-flattened short stubble. Leaving tall stubble at harvest should be considered to reduce Russian thistle plant dispersal if the infestation is going to be left untreated after harvest. Otherwise, short stubble might result in better Russian thistle control when using systemic herbicides, such as glyphosate.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48874530","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}

{"title":"Cereal rye residue management tactics influence inter- and intra- row weed recruitment dynamics in field corn when planting green","authors":"John M. Wallace, Tosh Mazzone, Zachary Larson","doi":"10.1017/wet.2023.56","DOIUrl":"https://doi.org/10.1017/wet.2023.56","url":null,"abstract":"\u0000 Delaying cover crop termination until cash crop planting (i.e., planting green) is an emerging no-till practice. Improved management recommendations are needed for optimizing weed suppression benefits while minimizing other pest, fertility, and crop management risks when planting green in corn production systems. In a 2-yr field experiment, we evaluated the interaction between cereal rye residue management tactics (standing residue, roll-crimping, roll-crimping with row cleaners) and herbicide programs (1-pass PRE, 2-pass POST) when planting green on weed recruitment spatial patterns and corn performance compared to standard termination (14 d pre-plant; 14 DPP) and ryelage harvest (14 DPP) practices. In a 2-yr on-farm experiment, we evaluated corn performance in response to the same residue management tactics. Cereal rye biomass production varied significantly across years in on-station experiments, with average (4.9 Mg ha-1) and anomalous (9.9 Mg ha-1) levels observed in 2020 and 2021, respectively. In 2020, planting green with an integrated roll-crimper/row cleaner system resulted in greater intra-row weed density compared to planting green into standing cereal rye. Inter-row weed density was lower when employing roll-crimping compared to early-termination (14 DPP). Planting green into standing cereal rye resulted in greater mean corn height (V5 stage) compared to other treatments but corn population and yield did not differ. In 2021, few differences in weed recruitment patterns were observed, but corn population and yield were significantly lower in planting green treatments compared to early termination. Across years, late-season weed biomass was lower in two-pass POST programs compared to one-pass PRE programs. On-farm trials showed that planting green into standing residue increases corn height, and can reduce corn populations, which may lead to reduce yields. Our results suggest that management recommendations for optimizing herbicide application timing should consider intra- and inter-row weed recruitment dynamics associated with residue management tactics needed to optimize corn performance.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47653574","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}

{"title":"Characterization of Imazamox-Resistant Shattercane (Sorghum bicolor L.) Populations from Kansas","authors":"Vipan Kumar, R. Liu, Deepika Chauhan, Ramasamy Perumal, Sarah Morran, T. Gaines, Prashant Jha","doi":"10.1017/wet.2023.55","DOIUrl":"https://doi.org/10.1017/wet.2023.55","url":null,"abstract":"\u0000 Shattercane is a problematic summer annual grass weed species in grain sorghum producing regions, including Kansas. Three shattercane populations (DC8, GH4, and PL8) collected from sorghum fields from northwestern Kansas survived the field-use rate (52 g ha-1) of postemergence applied imazamox. The main objectives of this research were to (1) confirm and characterize the level of resistance to imazamox in those putative imazamox-resistant (IMI-R) shattercane populations, (2) investigate the underlying mechanism of resistance, and (3) determine the effectiveness of postemergence herbicides for controlling IMI-R populations. A previously known imazamox susceptible (SUS) shattercane population from Rooks County, KS was used. All three putative populations exhibited a 4.1- to 6.0-fold resistance to imazamox compared to the SUS population. The ALS gene sequences from all IMI-R populations did not reveal any known target-site resistance mutations. A pretreatment of the cytochrome P450-inhibiting insecticide malathion followed by imazamox at various doses reversed the resistance phenotype of PL8 population. In a separate greenhouse study, the postemergence treatments of nicosulfuron, quizalofop, clethodim, and glyphosate provided ≥96% injury to all IMI-R populations. The lack of known ALS target-site mutations and the reversal of resistance phenotype by malathion suggest the possibility of metabolism-based resistance to imazamox in PL8 shattercane population.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44714714","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}