Postemergence Research Articles

Gambaran Post Traumatic Growth Pada Pasien Kanker Serviks Paska Histerektomi

Cervical cancer is a gynecology disease and primarily cause of woman death, hysterectomy is a surgical procedure to remove partially or totally the uterus. Hysterectomy is one of the surgical actions that causes anatomical changes. This research aims to examine the dynamics on overview of post traumatic growth emergence women with servical cancer post hysterectomy. This study used a qualitative approach three participants who were joined this study were gained by purposive sampling method. Data obtained through observation and interview with subject and significant others. The data collection technique is interview with general guidelines. The study subjects were three early adult woman 30-45 years old, who have hysterectomy between 1-2 years in the Obstetrics and Gynecology Clinic Cipto Mangunkusumo Hospital, Jakarta. Results showed in the process of post traumatic growth, all subjects demonstrated positive change toward higher level of change in perception, relation with others and change in philosophy of life. Change in philosophy of life was found to be the most dominant dimension. Subjects can develop themselves toward psychological growth which is better than ever. This process is also influenced by the presence of presence of social support and believe in God

Performance of Various Weed Management Approaches on Weed Dynamics, Yield Attributes and Yield of Puddled Rice under Different Planting Techniques

Background: Rice is a major food source worldwide and direct seeding can shorten crop duration and reduce labour. The system of rice intensification (SRI) can boost yields with fewer inputs. Weed management is crucial for high yields, but chemical herbicides may not be necessary with SRI. A study evaluated herbicide performance based on rice establishment methods. Methods: An field experiment was conducted in January to May, 2021 (Navarai) to find out the efficient weed control techniques in puddled rice. The experiment has been carried out in split-plot design, which included two planting techniques viz., drum seeded rice and system of rice intensification (SRI) in main plot, as well as eight weed control techniques viz., hand weeding, cono weeding, pretilachlor, bispyribac sodium and fenoxaprop - p - ethyl as pre and post emergence application in sub plot. Result: The results of the experiment demonstrated that among the planting techniques and weed management practices tested, the system of rice intensification and sequential application of pretilachlor @ 0.5 kg a.i ha-1 fb bispyribac sodium @ 20 g a.i ha-1 has revealed lowest weed density and highest weed control efficiency, yield attributes and yield and energetics.

Multiple herbicide-resistant kochia (Bassia scoparia) control in glufosinate-resistant canola

Multiple herbicide-resistant kochia ( Bassia scoparia (L.) A.J. Scott) has grown in prevalence in the canola ( Brassica napus L.) production region of North America. Glufosinate-resistant canola facilitates kochia management since glufosinate-resistant kochia is not known to occur. Field experiments were conducted from 2013 to 2015 in five environments near Lethbridge and Coalhurst, Alberta, to identify herbicide strategies targeting acetolactate synthase inhibitor-resistant kochia with and without glyphosate resistance in glufosinate-resistant canola. Sequential glufosinate treatments (500 g ai ha−1) postemergence (POST) caused excellent (≥90%) kochia control and biomass reduction across environments. Preplant (PP) carfentrazone + sulfentrazone (9 + 105 g ai ha−1) alone or followed by (fb) POST glufosinate (9 + 27 fb 500 or 9 + 105 fb 500 g ai ha−1) resulted in excellent kochia control in all environments tested. PP carfentrazone + sulfentrazone (9 + 53 g ai ha−1) alone, and a single POST treatment with glufosinate (500 or 590 g ai ha−1) alone or preceded by fall-applied ethalfluralin (1100 fb 500 g ai ha−1) with or without PP carfentrazone (1100 fb 9 fb 500 g ai ha−1) caused ≥80% kochia control and biomass reduction in all environments tested. However, treatments containing PP carfentrazone + sulfentrazone caused unacceptable canola injury or yield loss in at least one environment. In conclusion, single or sequential treatments of glufosinate POST managed multiple herbicide-resistant kochia effectively in canola. Layering fall-applied/PP ethalfluralin and/or PP carfentrazone with glufosinate POST may help alleviate resistance selection pressure placed on glufosinate in canola.

Assessing the Combined Effects of Host and Parasite Exposure to Forever Chemicals in an Amphibian-Echinostome System.

Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants of growing concern due to their potential negative effects on wildlife and human health. Per- and polyfluoroalkyl substances have been shown to alter immune function in various taxa, which could influence the outcomes of host-parasite interactions. To date, studies have focused on the effects of PFAS on host susceptibility to parasites, but no studies have addressed the effects of PFAS on parasites. To address this knowledge gap, we independently manipulated exposure of larval northern leopard frogs (Rana pipiens) and parasites (flatworms) via their snail intermediate host to environmentally relevant PFAS concentrations and then conducted trials to assess host susceptibility to infection, parasite infectivity, and parasite longevity after emergence from the host. We found that PFAS exposure to only the host led to no significant change in parasite load, whereas exposure of parasites to a 10-µg/L mixture of PFAS led to a significant reduction in parasite load in hosts that were not exposed to PFAS. We found that when both host and parasite were exposed to PFAS there was no difference in parasite load. In addition, we found significant differences in parasite longevity post emergence following exposure to PFAS. Although some PFAS-exposed parasites had greater longevity, this did not necessarily translate into increased infection success, possibly because of impaired movement of the parasite. Our results indicate that exposure to PFAS can potentially impact host-parasite interactions. Environ Toxicol Chem 2024;43:1537-1546. © 2024 SETAC.

Enhancing Summer Soybean Yield through Evaluation of Herbicidal Weed Management Options

The farmers of Gujarat have turned to soybean cultivation as soybean demand is increasing promisingly. Improper weed management is one of the reasons for the large yield gap between the potential and the actual yield of soybean harvested by the farmers. So, the selection of different herbicides in soybean is necessary for effective management of complex weed flora. An experiment was plotted with an aim of enhancing summer soybean yield through evaluation of herbicidal weed management options on medium black calcareous soil at Junagadh Agricultural University, Junagadh during summer season of 2021. The experiment comprised 12 treatments that were arranged in randomized block design with 3 replications. The outcomes of the results revealed that following to weed-free treatment, pre-mix pendimethalin + imazethapyr 750+50 g/ha as pre-emergence (PE) fb hand-weeding (HW) & inter-culturing (IC) at 30 days after sowing (DAS), HW at 15 DAS fb pre-mix propaquizafop + imazethapyr 50+75 g/ha as post-emergence (PoE) at 30 DAS, HW at 15 DAS fb pre-mix fluazifop-p-butyl + fomesafen 125+125 g/ha (PoE) at 30 DAS and pre-mix pendimethalin + imazethapyr 750+50 g/ha (PE) fb pre-mix fluazifop-p-butyl + fomesafen 125+125 g/ha (PoE) at 30 DAS enhanced growth parameters viz., plant height, branches per plant; yield attributes i.e., number of pods per plant and ultimately lead to greater seed yield and stover yield. These herbicidal weed management options also reduced population in addition to dry matter of weeds and had less reduction in yield due to better control of weeds, less crop-weed competition and higher weed control efficiency.

Pyroxasulfone based tank-mix herbicide combinations for diverse weed flora control in wheat

Field studies were conducted to assess the efficacy of pyroxasulfone alone and its combinations with other herbicides at different time of application against a diverse weed flora in wheat (Triticum aestivum L). Applications of pyroxasulfone at 125 g/ha as pre-emergence (PE) or early post-emergence (EPO) at 20 days after sowing effectively controlled the grass weeds (Phalaris minor Retz. and Avena ludoviciana Durieu). However, pyroxasulfone alone exhibited poor control of broad-leaved weeds, such as Medicago denticulata Willd and Rumex dentatus L. To address the limitations in controlling broad-leaved weeds, tank mix combinations of pyroxasulfone at 125 g/ha with either pendimethalin at 1000 g/ha or metsulfuron at 4 g/ha or metribuzin at 300 g/ha proved highly effective. Pre-emergence pyroxasulfone application in combination with either metsulfuron (125 + 4 g/ha) or with metribuzin (125 + 300 g/ha) in wheat gave effective control of diverse weed flora and improved wheat productivity by 52.1% and 51.2%, respectively, over untreated control. Ready mix combination of clodinafop + metribuzin 60 + 210 g/ha applied as post emergence (32 DAS) provided >99% control of P. minor, A. ludoviciana, M. denticulata and R. dentatus L., however the phytotoxicity with this treatment produced 6.7% lower yield as compared to season long weed free conditions. Among the herbicidal treatments, pre-emergence application of pyroxasulfone + metsulfuron at 125 + 4 g/ha had the highest net returns followed by alone application of pre-emergence metribuzin at 300 g/ha.

Application and Effects of Different Herbicides against Weed Flora in Wheat Crop for Sustainable Agriculture

Weed management is a sustainable approach which promotes the majority of crop production. To control weeds in various cropping systems, farmers employ a variety of techniques, although nowadays, the most popular method is the application of herbicides, which can be attributed to labour shortage. Application and effects of different herbicides against weed flora in wheat crop for sustainable agriculture," was conducted in 2020 and 2021. The experiment's goal was to assess how many herbicides performed against complex weed flora in wheat crop. The experiment was planned and laid out with nine treatments which are pre-emergance application of pendinethalin 1.0 kg a.i. ha-1 at (3 DAS) (T2) and post emergence application of metribuzin 0.3 kg a.i. ha-1 (T1), sulfosulfuron 0.03 kg a.i. ha-1 (T3), metsulfuron-methyl 0.005 kg a.i. ha-1 (T4), clodinafop-propargyl 0.04 kg a.i. ha-1 kg (T5), 2,4-D 0.6 kg a.i. ha-1 (T6), carfentrazone-ethyl 0.025 kg a.i. ha-1 (T7), weed free (T8) and weedy check (T9) and four replications under randomized block design. The major weeds infesting the wheat crop field were Anagallis arvensis, Chenopodium album, Phalaris minor, Parthenium hysterophorus and Cyperus rotundus. The post-emergence application of carfentrazone-ethyl 0.025 kg a i/ha at 33 days after sowing was most efficient in controlling the weeds (both grassy and non-grassy) among the various applied herbicides. Weed growth suppression effect of carfentrazone-ethyl 0.025 resulted significant increase the growth parameters, yield attributes and higher economic yield of wheat over check control in order to promote the sustainability.

Analyzing the synergistic impact of UAV-based technology and knapsack sprayer on weed management, yield-contributing traits, and yield in wheat (Triticum aestivum L.) for enhanced agricultural operations

Modern agriculture uses agrochemicals to boost crop yield and quality. Using knapsack sprayers, Indian farmers apply herbicides, insecticides, and other chemicals. Herbicides are applied by manually operated knapsack sprayers, which are laborious, uneven, and prone to human mistakes. Unmanned aerial vehicles (UAVs) are a promising agricultural spraying alternative to manual operations. Future agricultural and field scouting technology aids weed management, pest control, and automated irrigation systems. Drone herbicide spraying was compared to traditional and mechanical knapsack sprayers in this study. The study also tested knapsack (manual) and UAV herbicide pre- and post-emergence and spraying on wheat crops. Herbicide application by knapsack and drones was examined for weed control, yield-contributing characters, and wheat yield. The experiments were performed at Vasantrao Naik Marathwada Krishi Vidyapeeth's Department of Agronomy in Parbhani, Maharashtra. A randomized block design (RBD) with eight treatments, including drones and knapsack sprayers for weed management in wheat crops with different herbicide application times and repeated hoeings (cultural method), was compared to absolute weed-free, where no weeds were allowed to grow in wheat by frequent weeding and weedy inspection. The experimental field measured 7.2 m x 6 m gross land area and 6.3 m x 5.6 m net land area. When winds were light, the drone was flown at 3 m to avoid herbicide droplets drifting. The study found that unweeded wheat yields dropped 38 % owing to weed insects. The pre-emergence (PE) application using a knapsack sprayer and post-emergence (POE) herbicide application via a drone synergistically resulted in the highest growth and yield for T3, attaining values of 11.02 gm/plant, an average of 284.97 grains/plant, and a per-hectare grain yield of 4256.59 kg/ha. The cultural approach of weed management (T4) reduced yield by 21.2 %; however, treatment T3 improved yield contributing characteristics and losses by just 2.8 %. UAV-based herbicide spraying is a fast and easy method that contributes to achieving sustainable development goal (SDG) 2 for Zero Hunger by promoting sustainable plant protection and crop production.

Residual phytotoxicity effects of different integrated herbicides management in soils from field-treated plots and post-harvest field

Soil residual phytotoxicity of commonly used herbicides in cotton crop in India were investigated through bioassay. Pendimethalin at 900 g a.i. ha-1, oxyfluorfen at 180 g a.i. ha-1, oxadiargyl at 90 g a.i. ha-1, quizalofop-ethyl at 40 g a.i. ha-1, imazethapyr at 75 g a.i. ha-1, propaquizafop at 50 g a.i. ha-1 and glyphosate at 960 g a.i. ha-1 were applied to field plots of 6.0 x 6.0 m2. Sorghum and cucumber were used in the bioassay and succeeding crops groundnut, green gram & pearl millet to test the residual effect of herbicides in the soil of the treated plots and post-harvest field. Soil, sampled at 30 day after treatment (DAT) for pre emergence herbicide and until 2 weeks (WAT) for post emergence herbicide later, show significant affect the seed germination and seedling development stage of sorghum and cucumber. There was no residual toxicity of pre and post-emergence herbicides as observed through field bioassay after harvesting cotton crop and it was found safe to grow groundnut, green gram and pearl millet as succeeding crop.

Weed seedbank as influenced by tillage and herbicide in direct seeded rice‐mustard cropping sequence in lateritic soil of eastern India

AbstractThe above‐ground community dynamics of weeds represent the soil weed seedbank in an agro‐ecosystem. Hence, understanding the seedbank will offer an idea for future weed management tactics. We aimed to determine the density of weed seedbank and emergence of major weeds in direct seeded rice (DSR) (Oryza sativa L.)—mustard (Brassica campestris L. var. yellow sarson) cropping sequence under varied tillage and herbicide combinations. The present study on weed seedbank was conducted using seedling emergence method after collecting the soils at the harvest of mustard at the completion of 2 years field experimentation. The experiment was conducted in split‐plot design with two tillage practices [zero tillage (ZT) and conventional tillage (CT)] in main plot and eight weed management practices in DSR [oxadiargyl followed by (fb) bispyribac‐sodium, penoxsulam + cyhalofop‐butyl, oxadiargyl fb penoxsulam + cyhalofop‐butyl, fenoxaprop‐p‐ethyl + ethoxysulfuron, oxadiargyl fb fenoxaprop‐p‐ethyl + ethoxysulfuron, pendimethalin fb bispyribac‐sodium, unweeded control, and weed free check] as subplot. The carry‐over effect of tillage and weed management practices were recorded in mustard crop. Seed emergence study revealed that ZT reduced the emergence of grassy weeds (by 13.7%) and total weed emergence (19.5%) in comparison to the CT (p < 0.05). However, emergence of broadleaf weeds was 24.5% higher in ZT than in CT. The higher infestation was recorded for Ludwigia parviflora (Jacq.) Raven under penoxsulam + cyhalofop‐butyl, fenoxaprop‐p‐ethyl + ethoxysulfuron, Cyperus iria (L.) under fenoxaprop‐p‐ethyl + ethoxysulfuron, and Eleusine indica (L.) Gaertn. under pendimethalin fb bispyribac‐sodium, oxadiargyl fb bispyribac‐sodium. Sole application of post‐emergence (POE) herbicide decreased the total weed emergence by 22.2%–28.1% than unweeded control (p < 0.05). Whereas, sequential application of PRE + POE herbicides decreased the total weed emergence by 32.8%–36.9% than unweeded control (p < 0.05). Notably, sedge weeds such as Cyperus iria (L.) and Fimbristylis miliacea (L.) Vahl were lower in ZT than in CT under herbicide treated plots (by 66.6%–84.3%) than unweeded control. Thus, ZT with oxadiargyl 90 g a.i. ha−1 fb fenoxaprop‐p‐ethyl + ethoxysulfuron (90 + 15 g a.i. ha−1) as tank‐mix can be effectively used to lower the weed seedbank density vis‐à‐vis managing complex weed flora in DSR and rice‐mustard cropping sequence.

Weed management in soybean using early post emergence herbicide in lateritic soil and residual effects of herbicide in succeeding crops

Weed management in soybean using early post emergence herbicide in lateritic soil and residual effects of herbicide in succeeding crops

Studies on weed density and weed control efficiency of post emergence herbicides in wheat (Triticum aestivum L.)

Studies on weed density and weed control efficiency of post emergence herbicides in wheat (Triticum aestivum L.)

Studies on Chemical Weed Management Practices on Growth and Yield of Blackgram [Vigna mungo (L.)

An investigation was carried out at Zonal Agricultural Research Station, Kalaburagi, University of Agricultural Sciences, Raichur during kharif 2021-22 entitled studies on chemical weed management practices on growth and yield of blackgram [Vigna mungo (L.)]. The experiment was laid out in randomized complete block design with nine treatments and three replications. Among all the treatments, hand weeing at 25-30 DAS, recorded significantly lower weed density, higher weed control efficiency that favoured higher growth and yield parameters. Whereas, among the chemical weed management practices, application of sodium acifluorfen 16.5% + clodinafop propargyl 8% EC @ 1.0 kg a.i. ha-1 at 20-25 DAS as post emergent recorded significantly lower weed population (2.71/0.25 m2), lower weed dry weight (1.53/0.25 m2) and higher weed control efficiency (90.31 %) compared to other chemical weed management treatments. The treatment sodium acifluorfen 16.5% + clodinafop propargyl 8% EC @ 1.0 kg a.i. ha-1 at 20-25 DAS as post emergent also recorded significantly higher growth parameters viz., plant height (40.18 CM), number of branches (9.18), and dry matter production at harvest (23.50 g plant-1) and yield components viz., number of pods plant-1 (46.69 ), number of seeds pod-1 (7.89), 100 seed weight (4.7 g), seed yield (1059 kg ha-1) compared to other treatments. Significantly higher net returns (Rs.48,406) were recorded in hand weeding at 25-30 DAS and intercultivation at 45 DAS, which was on par with application of sodium acifluorfen 16.5% + clodinafop propargyl 8% EC @ 1.0 kg a.i. ha-1 at 20-25 DAS (Rs.45,066 ha-1). The higher benefit cost ratio was recorded with application of sodium acifluorfen 16.5% + clodinafop propargyl 8% EC @ 1.0 kg a.i. ha-1 at 20-25 DAS (3.08) followed by hand weeding at 25-30 DAS and intercultivation at 45 DAS.

Johnson Grass (Sorghum halepense) Interference, its Effect on Crops Yield and Soil attributes under Different Cropping Systems and Management Practices

Johnson grass (Sorghum halepense) is one of the most detrimental and toxic weeds among the weed species. Its environment is expanding unceasingly due to deeply expanding of its rhizomes in the soil, self-pollinating reproduction strategy, accelerated growth and poor management which results in production losses of major agronomic crops. Mungbean and sorghum are important crops grown on significant acreage around the world, and a major constraint for their production losses is weeds interference. Thus, field studies were conducted to examine Johnson grass interference, control, and recovery under different management practices and cropping system and its effects on crops production and soil health. Our results indicated that the Johnson grass density was minimized by the application of plastic sheet mulch treatment under wheat-mungbean cropping system. Johnson grass competition had a significant impact on growth and grain yield of both mungbean and sorghum. The crop yield parameters; 100 grain weight and grain yield were lowest in the non-treated treatment (control), while the greatest values of these parameters were recorded in the plastic sheet mulch and post emergence herbicide treatments with wheat-mungbean cropping system. Similarly, soil building attributes; available nitrogen, available phosphorus, available potassium and organic matter content were positively affected by the interaction of plastic sheet mulch + wheat-mungbean cropping system. Besides this, benefit-cost ratio of the research shows that wheat-mungbean cropping system with application of plastic sheet mulch and post emergence herbicide also proved to be economically feasible. Overall, we have concluded that wheat-mungbean and wheat-sorghum are most resilient cropping system with the implementation of plastic sheet mulch and Post Emergence Herbicide to suppress the spread of Johnson grass under changing climatic scenarios.

Evaluation of different weed management practices on growth and yield of transplanted rice (Oryza sativa L.) in Northeastern Zone of Tamil Nadu

Weeds cause a 57 per cent yield loss in transplanted rice and an 82 per cent yield loss in direct seeded rice, resulting in a $4.20 billion monetary loss per year. Weed infestation, species richness, density, dry matter accumulation and duration of association significantly affects rice grain production. Therefore, a field experiment was conducted in farmer’s field in Thiruvennainallur village, Villupuram District, Tamil Nadu, India during Navarai season of 2021, in order to evaluate the different weed management practices on growth and yield of rice under transplanted conditions. The experiment was laid out in a randomized block design, having fourteen treatment and replicated thrice. Treatment consists of hand weeding, butachlor, pretilachlor, pyrazosulfuron ethyl, bispyribac sodium, fenoxaprop-p-ethyl, Triafamone + ethoxy sulfuron, metsulfuron methyl + chlorimuron ethyl and penoxsulam + cyhalofop butyl were used as herbicides. Among the different herbicides tried out, pre emergence application of pyrazosulfuron ethyl 10% WP @ 0.15 g/ha fb post emergence application of bispyribac sodium 10% SC @ 0.25 l/ha recorded least weed density (15.55, 29.56 m-2), weed biomass (8.25, 16.02 g/m2) with weed index (2.18 %) and highest weed control index (89.22%, 85.18%), plant height (97.21 cm), dry matter production (12735 kg/ha), number of productive tillers/m2 (349.23), grain yield (6416 kg/ha) and straw yield (7839 kg/ha). Sequential application of pre-emergence followed by post emergence enhance the reduction of weed leads to higher productivity of transplanted rice.

A Multimethod Exploration of the COVID-Era Transition to Virtual Hearings in Child Welfare Court Cases.

To promote open and safe access to court hearings for families and professionals during the COVID-19 pandemic, juvenile and family courts across the United States shifted towards virtual hearings in child welfare cases. Drawing on findings from a four state court observation study conducted pre and post emergence of the pandemic, as well as from a national survey of court professionals and a survey of parents, we reflect on the experiences of courts and court participants with virtual hearings in child welfare cases and specific impacts on hearing quality. Findings indicate that despite stakeholder perceptions, there is little difference in the quality of hearings with respect to judicial engagement and discussion. Differences were found however, in the attendance of fathers and relatives at hearings, with less fathers and relatives attending virtual hearings. Parents had mixed experiences with the virtual hearing process. Professionals noted challenges, as well as strategies for overcoming challenges, to engage parents and ensure their access to virtual hearings.

Novel use pattern of pendimethalin for annual ryegrass (Lolium rigidum Gaudin) control in wheat and barley

Annual ryegrass (Lolium rigidum Gaudin) is a problematic weed in most of the cropping regions in Australia. Evolved herbicide resistance to multiple modes of action groups, the lack of new herbicidal molecules, and the emergence of late cohorts in winter season crops necessitate the use of existing herbicides in an innovative way to control L. rigidum. Pendimethalin as pre-emergence (PRE) is used for L. rigidum control; however, it is unable to control late cohorts of L. rigidum in winter season crops. Pot studies were conducted from 2019 to 2021 to evaluate the effect of a post-emergence (POST) application of pendimethalin with six doses (0, 220, 440, 880, 1,760, and 3,520 g a.i. ha-1) on L. rigidum control in addition to crop safety in wheat, barley, and sorghum. POST application of pendimethalin was found to be safe for wheat and barley, and the biomass reduction in both crops at varied rates (220 to 3,520 g ha−1) of pendimethalin ranged from 10% to 20%. A dose–response study revealed that the pendimethalin dose required for 50% mortality and growth reduction of L. rigidum was 179 and 144 g ai ha−1, respectively. Pendimethalin at 880 g ai ha−1 completely killed late cohorts of L. rigidum. These results suggest that the POST application of pendimethalin can be used for the effective control of late cohorts of L. rigidum in wheat and barley crops. POST application of pendimethalin suppressed the biomass of sorghum plants compared with the non-treated control treatment, and biomass reduction in sorghum at different pendimethalin doses ranged from 32% to 40%. Results implied that POST applications of pendimethalin in wheat and barley can diversify herbicide programs in managing L. rigidum and may help in delaying the evolution of resistance in this weed.

Integrating cover crops and herbicides for weed control in soybean

Abstract In mid-southern, southeastern, and northeastern U.S. soybean production regions, the evolution of herbicide-resistant weeds has become a significant management challenge for growers. The rising herbicide costs for managing herbicide-resistant weeds are also a growing concern, leading to the utilization of cover crops as an integrated weed management strategy for addressing these challenges. Field experiments were conducted at two locations in Alabama in 2022 to evaluate winter cereal cover crops, including a mixture and herbicide system integration in soybean. Treatments included five cover crops: oats, cereal rye, crimson clover, radish, and a cover crop mixture. Cover crops were evaluated for their weed-suppressive characteristics compared to a winter fallow treatment. Additionally, four herbicide treatments were applied: a preemergence (PRE) herbicide, a postemergence (POST) herbicide, PRE plus POST herbicides, and a nontreated (NT) check. The PRE herbicide was S-metolachlor; the POST treatment contained a mixture of dicamba and glyphosate. The PRE plus POST system contained the PRE application followed by POST application. Results show that cereal rye and the cover crop mixture provided weed biomass reduction compared to all cover crop treatments across both locations. Furthermore, we observed greater soybean yield following the cereal rye cover crop than following the winter fallow treatment at one location. POST and PRE plus POST herbicide treatment resulted in greater weed biomass reduction and improved soybean yield than the PRE herbicide treatment alone and the NT check at both locations.

Confirming resistance to PPO-inhibiting herbicides applied preemergence and postemergence in a Georgia Palmer amaranth population

Abstract Herbicides that inhibit protoporphyrinogen oxidase (PPO) are used in more than 40 agronomic and specialty crops across Georgia to manage weeds through residual and postemergence (POST) control. In 2017, a population of Palmer amaranth exhibiting reduced sensitivity to POST applications of PPO-inhibiting herbicides was identified by the University of Georgia. Seed were collected from the site along with a known sensitive population; distance between the samples was 200 m, increasing the likelihood of similar environmental and genetic characteristics. To quantify sensitivity for both preemergence (PRE) and POST uses, 21 greenhouse dose-response assessments were conducted from 2017 to 2022. After conducting initial rate-response studies, 13 doses per herbicide were chosen for the POST experiment; field use rates of fomesafen (420 g ai ha−1), lactofen (219 g ai ha−1), acifluorfen (420 g ai ha−1), and trifludimoxazin (25 g ai ha−1) ranging from 0× to 4× the field use rate for the susceptible population, and 0× to 40× for the suspect population were applied. Herbicide treatments included adjuvants and were applied to plants 8 to 10 cm in height. Relative resistance factors (RRFs) were calculated for control ratings, mortality, and biomass, and ranged from 105 to 318, 36 to 1,477, 215 to 316, and 9 to 49 for fomesafen, lactofen, acifluorfen, and trifludimoxazin, respectively. In the PRE experiment, herbicide applications included five to nine doses of fomesafen (1× = 210 g ai ha−1), flumioxazin (1× = 57 g ai ha−1), oxyfluorfen (1× = 561 g ai ha−1), and trifludimoxazin (1× = 38 g ai ha−1); doses ranged from 0× to 6× for the suspect population and 0× to 2× for the susceptible population. Visual control, mortality, and biomass RRFs ranged from 3 to 5 for fomesafen, 21 to 31 for flumioxazin, 6 to 22 for oxyfluorfen, and 8 to 38 for trifludimoxazin. Results confirm that a Georgia Palmer amaranth population is resistant to PPO-inhibiting herbicides applied both PRE and POST.

Common ragweed (Ambrosia artemisiifolia L.) accessions in the Mid-Atlantic region resistant to ALS-, PPO-, and EPSPS-inhibiting herbicides

Abstract Common ragweed is a troublesome weed in many crops. Farmers and crop advisors in the coastal Mid-Atlantic region have reported inadequate control of common ragweed in soybean fields with glyphosate and other herbicide modes of action. To determine whether herbicide resistance was one of the causes of poor herbicide performance, 29 accessions from four states (Delaware, Maryland, New Jersey, and Virginia) where common ragweed plants survived herbicide applications and produced viable seeds were used for greenhouse screening. Common ragweed seedlings from those accessions were treated with multiple rates of cloransulam, fomesafen, or glyphosate, applied individually postemergence (POST). All accessions except one demonstrated resistance to at least one of the herbicides applied at twice the effective rate (2×), 17 accessions were two-way resistant (to glyphosate and cloransulam, or to glyphosate and fomesafen), and three-way resistance was present in eight accessions collected from three different states. Based on the POST study, five accessions were treated preemergence (PRE) with herbicides that inhibit acetolactate synthase (ALS), and two accessions were treated with herbicides that inhibit protoporphyrinogen oxidase (PPO). All accessions treated PRE with the ALS inhibitors chlorimuron or cloransulam demonstrated resistance at the 2× rates. Both accessions treated PRE with the PPO inhibitor sulfentrazone had survivors at the 2× rate. When the same accessions were treated PRE with fomesafen, one had survivors at the 2× rate, and one had survivors at the 1× rate. Results from these tests confirmed common ragweed with three-way resistance to POST herbicides is widespread in the region. In addition, this is the first confirmation that common ragweed accessions in the region are also resistant to ALS- or PPO-inhibiting herbicides when applied PRE.