Preemergence Herbicides Research Articles

Growth and yield of irrigated maize (Zea mays L.) as influenced by mechanization and nutrient management practices

Maize is a dominant and promising crop grown in almost all regions throughout the year for various purposes, owing to its wide adaptability. In India, the productivity of maize is low, which can be attributed to usage of conventional varieties, inadequate supply of organic and inorganic fertilizers, low adoption of mechanization practices, and the indiscriminate use of pesticides and fungicides etc. Among these factors, mechanization and nutrient management practices play a critical role in influencing productivity through supply of nutrients and ensuring timeliness of operations. Keeping in view the above facts, field experiments were conducted in the Department of Agronomy and the Department of Millets during Kharif seasons of 2018, 2019 and 2020 to study the growth and yield of irrigated maize as influenced by mechanization practices and nutrient management strategies. The results of mechanization experiment revealed that T3 - sowing by inclined plate planter (75 × 20 cm – drip tape irrigation) + spraying of pre-emergence herbicide (3 days after sowing (DAS) - after irrigation) + weeding by power weeder (30 - 35 DAS) achieved higher grain yield (5549 kg ha-1), net returns (Rs. 58, 158 ha-1), and B:C ratio (2.66). The results of nutrient management experiments revealed that the application of 250:75:75 kg NPK/ha (100% the recommended dose of fertilizer (RDF) achieved higher grain yield (7327 kg ha-1), net returns (Rs. 73518/ha) and B: C ratio (2.50) in maize (T2).

Postemergence giant ragweed management as affected by soil and cover crop management, soybean planting time, and preemergence herbicide application

Abstract Early soybean planting and cover crop adoption in the US Midwest prompt investigation into the impact of these practices on weed community dynamics and best management practices. While previous research has explored different aspects of giant ragweed control, the specific integration among soil management practices, including cover crop adoption, soybean planting timing, and herbicide use, has not been thoroughly investigated. This study assessed soil management, soybean planting time, and PRE herbicide application on giant ragweed control and soybean yield in Wisconsin and Nebraska in 2022 and 2023. The study included a factorial arrangement of four soil management treatments [conventional tillage, no-till, and fall-planted cereal rye early terminated and terminated at planting (planting green)]; two soybean planting times; and two PRE herbicide treatments (PRE and no PRE). Postemergence (POST) herbicides were applied when ∼50% of giant ragweed plants within each treatment reached ∼10 cm in height. In Nebraska, cereal rye and tillage treatments without a PRE had at least 67% lower giant ragweed density than no-till at POST. In no-till, densities were at least 60% lower with PRE compared to no PRE. In Wisconsin, cereal rye did not reduce giant ragweed density at POST compared to no-till, likely due to relatively low biomass accumulation. In contrast, delayed soybean planting reduced giant ragweed density for most treatments but lowered soybean yield in no-till and planting green treatments. The PRE herbicides had either no or positive effects on reducing giant ragweed density and increasing soybean yield. Overall, this study suggests that soil management and soybean planting timing are crucial for effective giant ragweed management in Wisconsin, where biotypes with a long emergence window during the spring and summer are present, while in Nebraska, soil management and soybean planting timing are less critical due to giant ragweed biotypes with an early and short emergence window in the spring.

Soil Residual Activity of Tetflupyrolimet and the Influence of Soil Moisture and Flood Timeliness on Barnyardgrass Efficacy

ABSTRACT Tetflupyrolimet is the first herbicide with a novel site of action to be commercialized for use in agronomic crops in three decades. Direct-seed rice field experiments were conducted at research facilities near Stuttgart (silt loam), AR, and Keiser (clay), AR, to evaluate tetflupyrolimet as a preemergence herbicide versus commercial standards. Greenhouse experiments determined the influence of soil moisture on pre- and postemergence (POST) barnyardgrass control with tetflupyrolimet and clomazone, and the impact of a delayed flood on efficacy when POST-applied. For the field experiments, clomazone, tetflupyrolimet, and quinclorac were applied individually PRE at 336 and 560, 134 and 224, and 336 and 560 g ai ha-1, respectively, on a silt loam and clay soil, along with clomazone plus tetflupyrolimet and clomazone plus quinclorac at the same rates. The soil moisture experiment included a single PRE and POST application of clomazone at 336 g ai ha-1, tetflupyrolimet at 134 g ai ha-1, and a mixture at the respective rates, on a silt loam soil at 50, 75, and 100% of field capacity. For the flood timing experiment, tetflupyrolimet was applied to 2- to 3-leaf barnyardgrass at 134 g ai ha-1, and a flood was established at 4 hr after treatment (HAT) and 5 and 10 d after treatment (DAT). Barnyardgrass control with a tetflupyrolimet and clomazone mixture was comparable to clomazone plus quinclorac when averaged over all evaluations on silt loam and clay texture soils (≥91%). Soil moisture interacted with herbicide treatments for PRE and POST barnyardgrass efficacy when averaged over DAT, with tetflupyrolimet plus clomazone generally providing the greatest and most consistent control across regimes. Flooding barnyardgrass at 4 HAT provided superior control to later flood timings. Tetflupyrolimet is an effective residual barnyardgrass herbicide, and the addition of clomazone will aid in providing consistent control across varying soil moisture conditions.

Seleção de herbicidas pré-emergentes para o trigo

ABSTRACT Weed control is a challenge in crop management due to the limited number of registered herbicides, especially for preemergent application. This study aimed to investigate the selectivity of pre-emergent herbicides with different mechanisms of action for wheat. The experiment consisted of two stages: the first involved screening under greenhouse conditions, and the second assessing the selected treatments under field conditions, with a focus on crop yield. Plant phytointoxication, crop stand, and shoot dry weight were assessed in the greenhouse experiment, and tillering, crop stand, plant height, canopy closure, yield, 1000-grain weight, and hectoliter weight in the field. Under greenhouse conditions, [imazapic + imazapyr], pendimethalin, isoxaflutole, florpyrauxifen, and halosulfuron-methyl produced the best results and were selected for the field experiment. Florpyrauxifen was the only herbicide that was selective both in greenhouse and field experiments. Isoxaflutole and trifluralin did not damage wheat in any of the field evaluations. Despite reducing crop performance in some assessments, pendimethalin and flumioxazin provided yield, hectoliter weight, and 1000-grain weight results equivalent to the herbicide-free control. Florpyrauxifen (1.08 g ha-1) was the most promising herbicide. Trifluralin (900 g ha-1), pendimethalin (1750 g ha-1), isoxaflutole (60 g ha-1), and flumioxazin (40 and 60 g ha-1) also produced grain yields equivalent to the control without herbicide.

Preemergence pyrimisulfan applications affect purple nutsedge (Cyperus rotundus L.) survival and reproduction

AbstractPurple nutsedge (Cyperus rotundus L.) is one of the most problematic turfgrass weeds due to an elevated growth rate, aggressive rhizomes, and prolific tuber production. Currently, limited preemergence herbicide options exist for the control of C. rotundus. Therefore, research was conducted in the greenhouse to examine preemergence activity of pyrimisulfan on C. rotundus control and reproduction. Seven tubers were planted in 1‐L pots containing native soil. Treatments were initiated on July 14, 2021 and consisted of single and sequential applications of granular‐applied pyrimisulfan, liquid‐applied pyrimisulfan, and liquid‐applied pyrimisulfan + dithiopyr. Sequential applications were made on September 3, 2021. A nontreated check was added for comparison. Pots were destructively harvested 12 weeks after initial treatment (WAIT). Shoot dry biomass (g), rhizome dry biomass (g), tuber dry biomass (g), and tuber number were determined for each pot. Tubers were tested for viability (%) using tetrazolium chloride. All herbicide treatments reduced the number of emerged plants, shoot dry biomass, rhizome dry biomass, tuber dry biomass, tuber number, and tuber viability compared to the nontreated. A single application of liquid‐applied pyrimisulfan reduced the number of emerged plants by 99% 10 WAIT and viable tubers by 100% 12 WAIT, compared to a single application of granular‐applied pyrimisulfan (70% and 87%, respectively). Sequential applications of granular‐applied pyrimisulfan provided similar results as all liquid‐applied pyrimisulfan treatments across response variables. Neither a sequential application nor the addition of dithiopyr increased liquid‐applied pyrimisulfan efficacy.

Influence of sowing dates and weeding regimes on growth attributes and maize dry fodder yield

Effective agricultural practices are pivotal for ensuring optimal crop yields and sustainable farming. Two critical factors that significantly influence crop productivity are the date of planting and the weeding regime. An experiment was carried out to investigate how the timing of planting and the frequency of weeding impact the growth characteristics and fodder yield of maize. The study involved three planting dates viz. 15 November (D1), 15 December (D2) and 14 January (D3) along with five different weeding regimes viz. no weeding (W0), two hand weedings at 15 and 30 days after sowing (DAS) (W1), pre-emergence herbicide (pendimethalin) + one hand weeding at 30 DAS (W2), post-emergence herbicide (pyrazosulfuran-ethyl) + one hand weeding at 30 DAS (W3), and pre-emergence herbicide (pendimethalin) + post-emergence (pyrazosulfuran-ethyl) herbicide (W4). The growth characteristics and the amount of dry fodder produced were notably affected by the timing of planting, the method of weeding and how these factors interacted. At harvest, the tallest plant (138.48 cm) and total dry matter production plant-1 (37.32 g) were recorded in the plants sown on 15 November with the application of pre-emergence herbicide (pendimethalin) + one hand weeding at 30 DAS. The maximum number of leaves plant-1 (13.33) and leaf chlorophyll content (116.60) were obtained from15 November with the application of pre-emergence herbicide (pendimethalin) + post-emergence (pyrazosulfuran-ethyl) herbicide and 14 January with the application of pre-emergence herbicide (pendimethalin) + one hand weeding at 30 DAS. The highest dry fodder yield (4.14 t ha-1) was achieved with maize planted on 15 November and treated with pre-emergence herbicide (pendimethalin) + one hand weeding at 30 days after sowing. Based on the study, it can be concluded that planting on November 15 using a pre-emergence + one hand weeding 30 days after sowing may result in the tallest plants, maximum total dry matter production and the maximum dry fodder yield of maize.

Chemical Control of the Invasive Weed Trianthema portulacastrum: Nethouse Studies.

Trianthema portulacastrum L. (Aizoaceae), commonly known as desert horse purslane or black pigweed, is a C4 dicot succulent invasive annual plant that is widespread in agricultural fields in Southeast Asia, tropical America, Africa, and Australia. In Israel, Trianthema portulacastrum is an invasive weed of increasing importance in agricultural fields, including mainly corn, tomato, alfalfa watermelon, and groundnut crops. The significance of this weed in crops has been recently reported in neighboring countries of Jordan and Egypt. In previous studies, we have examined and described the spread, biology, and germination requirements of Trianthema portulacastrum in Israel. The present study aimed to investigate the efficiency of single pre- and post-emergence herbicides and the combination of pre-applied herbicides for the control of this invasive weed in pots in a nethouse. We conducted three sequential experiments in a nethouse: (1) screening of pre-emergence herbicides, (2) screening of post-emergence herbicides, and (3) assessment of residual activity of combined pre-emergence herbicides in three distinct Hula Valley soil types. Efficacy was evaluated through weekly assessments of seedling emergence and vigor, with the final shoot fresh weight determined upon the experiment's completion. In all experiments, weekly counts and vigor estimation of T. portulacastrum seedlings were conducted, and shoot fresh weights were determined at the end of the experiments. The results of pre-emergence herbicide screening showed that Fomesafen, Terbutryne, Flurochloridon, Sulfosulfuron, Cyrosulfamid + Izoxaflutole, and Dimethenamid were the most effective herbicides, leading to complete eradication of T. portulacastrum plants. Results of the post-emergence screening revealed that Saflufenacil, Foramsulfuron, Tembotrione + Isoxdifen-ethyl, and Rimsulfurom Methyl completely controlled the weed. In the soil residual study, three herbicide combinations (Fomesafen + Terbutryn, Sulfosulfuron + Fomesafen, and Dimethenamid + Flurochloridon) provided effective control across all soil types. These findings provide a foundation for future field trials investigating integrated pre- and post-emergence herbicide programs for T. portulacastrum management in various crops.

Effectiveness of pre-emergence herbicides on weed population and yield of boro rice (cv. BRRI dhan58) under different dose

Weed management is crucial for optimal crop performance in rice cultivation. In this respect, an experiment was conducted at the Agronomy Field Laboratory (AFL), Bangladesh Agricultural University (BAU), Mymensingh, from December 2019 to May 2020 and aimed to evaluate the effectiveness of various herbicide treatments on weed management and crop performance in rice cultivation, focusing on the variety BRRI dhan58. The study included a control group and various herbicide treatments: half the recommended dose (RD), RD, and a double dose of pendimethalin, bensulfuron methyl + acetachlor, bensulfuron methyl + bispyribac sodium, pretilachlor, and butachlor. Eleven weed species from six families infested the plots. The results showed that double doses of pre-emergence herbicides resulted in lower weed populations (WP) (m-²), reduced weed dry weight (DW) (gm-2), and higher weed control efficiency (WCE %). The highest weed control efficiencies at 30 DAT were 94.58% for Bensulfuron methyl + Acetachlor and 94.38% for Pretilachlor. The double dose of Bensulfuron methyl + Acetachlor achieved the lowest WP and DW and the highest WCE. Crop performance improved significantly with the double dose of Bensulfuron methyl + Acetachlor, resulting in the highest PH, a more significant number of effective tillers (NET) hill-1, 1000-grain weight (TGW), grain yield (GY), straw yield (SY), biological yield (SY), and harvest index (HI). The second-highest GY was observed with the double dose of Bensulfuron methyl + Bispyribac sodium. The study concluded that the double dose of Bensulfuron methyl + Acetachlor was the most effective weed management strategy, leading to the highest grain yield in boro rice. These findings highlight that using a double dose of Bensulfuron methyl + Acetachlor not only offers superior weed control but also maximizes grain yield, making it the most effective weed management strategy for boro rice cultivation and a practical recommendation for farmers seeking to optimize productivity through targeted herbicide application.

Developing AI Smart Sprayer for Punch-Hole Herbicide Application in Plasticulture Production System

In plasticulture production systems, the conventional practice involves broadcasting pre-emergent herbicides over the entire surface of raised beds before laying plastic mulch. However, weed emergence predominantly occurs through the transplant punch-holes in the mulch, leaving most of the applied herbicide beneath the plastic, where weeds cannot grow. To address this issue, we developed and evaluated a precision spraying system designed to target herbicide application to the transplant punch-holes. A dataset of 3378 images was manually collected and annotated during a tomato experimental trial at the University of Florida. A YOLOv8x model with a p2 output layer was trained, converted to TensorRT® to improve the inference time, and deployed on a custom-built computer. A Python-based graphical user interface (GUI) was developed to facilitate user interaction and the control of the smart sprayer system. The sprayer utilized a global shutter camera to capture real-time video input for the YOLOv8x model, which activates or disactivates a TeeJet solenoid for precise herbicide application upon detecting a punch-hole. The model demonstrated excellent performance, achieving precision, recall, mean average precision (mAP), and F1score exceeding 0.90. Field tests showed that the smart sprayer reduced herbicide use by up to 69% compared to conventional broadcast methods. The system achieved an 86% punch-hole recognition rate, with a 14% miss rate due to challenges such as plant occlusion and variable lighting conditions, indicating that the dataset needs to be improved. Despite these limitations, the smart sprayer effectively minimized off-target herbicide application without causing crop damage. This precision approach reduces chemical inputs and minimizes the potential environmental impact, representing a significant advancement in sustainable plasticulture weed management.

Comparative analysis of weed management techniques in taro (Colocasia esculenta (L.) Schott)

Weed management poses a significant challenge in taro cultivation since it’s a long-duration crop grown during the monsoon season. The warm, humid conditions of its extended growing period promote rapid weed germination and growth, complicating weed management efforts. To address this issue, a study was conducted at the Bangladesh Agricultural Research Institute, Jashore, in 2021 and 2022 to evaluate sustainable weed management strategies for taro. The experiment, designed as a randomized complete block (RCB) with three replications, tested seven weed control methods: T1= straw mulching (SM), T2= pre-emergence herbicide+SM, T3= poly mulching (PM), T4= pre-emergence herbicide+PM, T5= intercropping+two hand-weeding, T6= pre-emergence herbicide, and T7= four hand-weeding, alongside T8= weed-free and T9= weedy control treatments. Results indicated that all mulching treatments achieved 70% to 80% weed control efficiency, significantly reducing weed growth up to 120 days after emergence (DAE). The intercropping+hand-weeding treatment provided 75% to 80% weed control up to 90 DAE. Among the mulches, straw mulching resulted in the tallest and widest plant base girths, leading to the highest yield and benefit-cost ratio, followed by other mulch and intercropping+hand-weeding treatments. Pre-emergence herbicide treatments were ineffective due to their short duration of action. Additionally, combining mulching (SM & PM) with pre-emergence herbicide offered no advantage over mulching alone. These findings highlight straw mulch as the most effective weed management strategy for taro, eliminating the need for herbicides. Where mulch is unavailable, intercropping combined with hand weeding can be a viable alternative for effective weed control.

Control of dicamba/glufosinate/glyphosate-resistant volunteer soybean in corn with preemergence and postemergence herbicides

Abstract The widespread adoption of multiple herbicide-resistant corn and soybean often causes the problem of volunteers in corn-soybean rotation, which necessitates alternative herbicides for effective management. The objective of this research was to evaluate preemergence (PRE) and postemergence (POST) herbicides labelled in corn for control of dicamba/glufosinate/glyphosate-resistant volunteer soybean. Field experiments were conducted from 2021 to 2023 near Clay Center, Nebraska. Two separate field experiments were conducted to evaluate 12 PRE and 14 POST herbicides to control volunteer soybean in Enlist corn. Soybean resistant to dicamba/glufosinate/glyphosate was planted perpendicular to corn rows to mimic volunteer soybean. Among PRE herbicides tested, acetochlor/clopyralid/flumetsulam (1,190; 1,050/106/34 g ai ha–1) and acetochlor/clopyralid/mesotrione (2,304; 1,961/133/210 g ai/ae ha–1) provided 97% and 99% control of volunteer soybean, respectively, in 2021, and 68% and 89% control, respectively, in 2023 at 42 d after PRE. Among POST herbicides tested, 2,4-D choline (1,064 g ae ha–1), acetochlor/clopyralid/mesotrione (2,304; 1,961/133/210 g ai/ae ha–1), atrazine/bicyclopyrone/mesotrione/S-metolachlor (2,409; 700/42/168/1,499 g ai ha–1), clopyralid/flumetsulam (192; 146/46 g ai ha–1), nicosulfuron + atrazine (34 + 1,120 g ai ha–1), and thiencarbazone-methyl/tembotrione + atrazine (76; 12/63 + 896 g ai ha–1) provided ≥ 97% volunteer soybean control, ≥ 94% density reduction, and ≥ 97% biomass reduction 28 d after POST herbicide application. Corn yield did not differ from the weed-free control in these treatments. The results of this study suggest that PRE and POST herbicides are available for control of dicamba/glufosinate/glyphosate-resistant volunteer soybean in Enlist corn, and careful selection of herbicide is required based on the herbicide-resistant soybean planted previous year.

Evaluation of Newly-transplanted Blackberry Tolerance to a Selection of Preemergence Herbicides

Abstract This trial assessed the effect of preemergence herbicides on newly transplanted blackberries. A two-year field trial was initiated in 2021 and conducted at two locations: Fayetteville, AR and Clarksville, AR. Seven treatments consisted of six preemergence herbicides (flumioxazin, mesotrione, napropamide, oryzalin, pendimethalin, and S-metolachlor) and one nontreated check. Preemergence herbicide treatments were applied to field plots of newly-transplanted blackberry plugs (var. ‘Ouachita’), using a CO2 backpack sprayer at 187 L ha-1 covering a 1 m swath, ensuring spray pattern overlap over newly planted blackberries in 2021 and reapplied in the same manner to established blackberries of the same plots in 2022. Data were collected on crop injury and plant height of blackberry plants in each plot. Yield data was collected in the second year, and fruit were analyzed for soluble solids content, pH, and average berry weight. In the first year mesotrione and flumioxazin treatments caused injury to newly transplanted blackberries, and mesotrione-treated blackberries (58% - Fayetteville, 29% - Clarksville) did not fully recover by 84 days after treatment (DAT). Napropamide, S-metolachlor, oryzalin, and pendimethalin did not cause crop injury over 6% throughout the 2021 season. In the second year (2022), no crop injury was caused by any herbicide treatments. Results from these trials verify that flumioxazin, napropamide, oryzalin, and pendimethalin at the tested rates would be appropriate options for weed control in newly planted blackberries. These results corroborate regional recommendations against the use of mesotrione in first year blackberry plantings. The findings from this trial indicate S-metolachlor would be safe for registration for use in blackberries, regarding crop injury and blackberry yield.

Evaluation of Four Control Methods Efficiency and Damage Mitigation of Field Dodder (Cuscuta campestris Yunck.) in Eggplant Cultivation

Field dodder (Cuscuta campestris Yunck.) is one of the most difficult parasitic weeds to control. This study was conducted in 2020 and 2021 to investigate the efficiency of four selected control methods against field dodder in eggplant. The treatments that were applied in the experiment were hand hoeing, black polyethylene mulch, pendimethalin as a pre-emergence herbicide, and rimsulfuron as a post-emergence herbicide. The hand hoeing treatment achieved the highest efficiency against field dodder among the weed control methods used, reaching 100% weed-free, followed by the mulch treatment, with 91.2% weed-free. When the field dodder was left without control, it caused a decrease in plant height by 31.13%, the number of fruits by 59.00%, and a loss in eggplant yield by 82.16%. Infection with field dodder usually results in failure of the eggplant flowers' pollination and then death, reduced quality of fruits, deformation in leaves, and cases of severe infection lead to the complete death of plants.

Efficacy of weed control and selectivity in soybean in the application of preemergent herbicides and their carryover in sorghum and maize

Further studies are necessary to evaluate not only the effectiveness of preemergent herbicides for weed control and selectivity in soybeans but also the potential carryover damage to crops planted in succession, such as sorghum and maize. This study aimed to assess the efficacy of preemergent herbicides in controlling Euphorbia heterophylla L. and Digitaria insularis L., as well as their selectivity in soybeans (Glycine max L.) and the residual effects on crops sown in succession, including maize (Zea mays L.) and sorghum (Sorghum bicolor (L.) Moench). Two field experiments were conducted with soybean, both in a randomized block design, consisting of the following treatments: sulfentrazone + diuron, flumioxazin + imazethapyr, diclosulam, sulfentrazone, s-metolachlor and flumioxazin, in addition to weeded controls and without weeding, with four replicates. Subsequently, the sowing of maize and sorghum was performed. Visual evaluations of weed control were performed at 14, 21, 28, 35 and 42 days after application of the treatments (DAA) and of phytotoxicity in soybean, sorghum and maize at 14, 21, 28, 35 and 42 days after planting emergence (DAE), and at the end, yield estimate. It was found that the sulfentrazone, sulfentrazone + diuron and imazethapyr + flumioxazin treatments were effective in controlling D. insularis and E. heterophylla up to 42 DAA. For sorghum and maize, no significant injury levels were observed for any treatment, with the exception of sulfentrazone alone, which provided significant reductions in productivity.

Optimizing cotton production through efficient weed management using herbicides: A promising solution for labour-scarce farming

Cotton, often referred to as ‘White gold’ and the ‘King of fibre crops’ holds a significant position as a cash and fibre crop in India. Weeds contribute to approximately 45 % yield reduction in cotton cultivation at the national lev?el, making weed management a critical factor in determining cotton productivity, particularly in high-density planting systems (HDPS). Effective weed control optimizes resource allocation, leading to improved growth parameters and higher yields. This study investigates the efficacy of various weed management practices, including pre-emergence and post-emergent herbicide applications, in enhancing cotton yield under HDPS. The results clearly demonstrate that a combination of PE Pendimethalin (1.0 kg a.i./ha), Metolachlor (1.0 kg a.i./ha), POE Pyrithiobac sodium (0.075 kg a.i./ha), and Quizalofop ethyl (0.075 kg a.i./ha) led to significantly greater plant height (113.4 cm) and dry matter production (7609 kg ha-1 ) . This treatment also resulted insignificantly improved yield parameters, with a higher seed cotton yield of 2098 kg ha-1 , and yielded higher net returns of Rs.141961 ha-1 and a Benefit Cost Ratio (BCR) of 3.09. In the face of increasing labour scarcity, these herbicide-based weed management practices offer a viable solution for maximizing cotton productivity under HDPS. This approach supports the rapid expansion of cotton acreage in the current era of farm mechanization.

Market Availability of Selective Post-emergence Herbicides for Major Food Crops in the Haut-Sassandra Region, Central-western Côte d'Ivoire

Weed control in crops is increasingly done by the chemical method in the Haut-Sassandra region. However, farmers in this region often struggle to obtain selective post-emergence herbicides for certain food crops. The purpose of this study was therefore to assess the availability of selective post-emergence herbicides of the main food crops of this region markets with a view to providing necessary information to effective weed management and ensure food security. In this context, a survey was conducted among 104 managers of phytosanitary product stores in the region. At the end of the investigations, 41, 34, 2, 5 and 4 trade names of selective post-emergence herbicides of rice, maize, cassava, yam and plantain were observed, respectively. The relative frequencies of these main food crops selective post-emergene were 92,00 %, 92,00 %, 5,00 %, 3,75 % and 1,75 %, respectively, on the regional market. They were divided into 9, 3, 2, 3 and 2 active ingredients, respectively. Selective post-emergence herbicides for rice and maize have been observed on the markets of the four departments of the region and the selective cassava herbicides in Daloa only. As for the selective post-mergence herbicides of yam and plantain, they were noted in Vavoua and Daloa. To effectively manage weeds in their crops, yam, cassava and plantain producers in the departments of Issia and Zoukougbeu and cassava growers in Vavoua can stock up on selective post-emergence herbicides in Daloa. They can also use selective pre-emergence herbicides for their crops or adopt stale seed bed.

Weed management in direct wet-seeded rice - A comprehensive review to higher productivity

This review examines various weed control strategies for Direct Seeded Rice systems. The diverse weed flora in DSR includes grasses (Echinochloa colona), sedges (Cyperus iria) and broadleaf weeds (Ludwigia parviflora) being prevalent. Integrated weed management combining cultural, mechanical, biological and chemical methods is recommended for sustainable control. Cultural practices such as stale seedbed techniques, crop rotations and flooding help suppress the growth of weeds. Mechanical methods, including hand weeding and the use of weeders, are effective but labour-intensive. Chemical control via pre-emergence (pretilachlor) and post-emergence (bispyribac-sodium) herbicides has shown promising results optimally. This review highlights that an integrated approach utilizing multiple complementary weed management tactics is essential for effective and sustainable weed control in direct-seeded rice. The proper timing of interventions, combinations of methods, and consideration of local conditions are essential factors. Although chemical herbicides are still valuable tools, there is a growing emphasis on reducing their use by integrating alternative methods. Overall, continued review of innovative biological and ecological approaches can further enhance the existing options for weed management in DSR systems.

Toxicological Effects of Pendimethalin: Behavioral Changes and LC50 Analysis in Cyprinus carpio

The pre-emergent herbicide pendimethalin is a selective dinitroaniline compound that interferes with the production of microtubules, potentially contaminating groundwater. The current investigation sought to ascertain the acute toxicity levels and behavioral effects of pendimethalin (30% EC) on Cyprinus carpio. Finney's probit bioassay method estimated the lethal toxicity LC50 values for commercial-grade herbicide pendimethalin on C. carpio. This method entails fitting the data collected from experiments to a probit model, which converts the results obtained (such as mortality rates) into a normal distribution scale. It is a useful tool in toxicological research since it enables more precise estimations of the LC50. The lethal toxicity (LC50) values of pendimethalin to C. carpio exposed to 24, 48, 72 and 96-hr were determined to be 2.83µL/L, 2.59µL/L, 2.39µL/L and 2.20µL/L based on the mortality estimations. Pendimethalin-induced behavioral abnormalities in C. carpio were investigated using sublethal concentrations (i.e., 1/15th, 1/10th, and 1/5th of the 96-hour LC50 value) at intervals of 0, 7, 14, 21 and 28 days. Our research observed behavioral shifts such as reduced general activity, reduced foraging behavior, diminished schooling behavior, reduced reflex stimuli, increased opercula movements, irregular movements, mucus secretion, enhanced breathing rates and increased surface air gulping. Our studies showed that pendimethalin can produce both mortality and behavioral alterations in Cyprinus carpio, offering important insights into the pendimethalin fatal and sub-lethal effects. These results highlight how crucial it is to keep an eye on herbicide poisoning in aquatic habitats since even sub-lethal levels can have an effect on fish behavior and the general health of the ecosystem.

Patterns of herbicide resistance in Raphanus raphanistrum revealed by comprehensive testing and statistical analysis.

Raphanus raphanistrum causes $40 million total revenue losses annually in Western Australia partly due to its historically-documented ability to evolve herbicide resistance to multiple modes of action. In this study, 376 field-sampled populations of R. raphanistrum were tested for resistance to 21 herbicides applied at the recommended label rate. Eight treatments were herbicide mixtures with two, three or four modes of action. A total of 7199 individual resistance tests were conducted across 4 years by screening approximately 104 000 individual seeds and seedlings. The mean survival of individuals within a population for all standalone herbicides was 9%, whereas survival was significantly decreased to 3.5% with a herbicide mixture. Some herbicides such as triasulfuron (herbicide Group 2), 2,4-D (Group 4) or diflufenican (Group 12) were highly impacted by resistance, with frequencies of resistant populations being > 50%. Conversely, there was negligible resistance to glyphosate (Group 9) or protoporphyrinogen oxidase (PPO) inhibitors (tiafenacil, saflufenacil + trifludimoxazin, fomesafen: Group 14), and pre-emergence herbicides (i.e., atrazine or mesotrione: Groups 5 and 27, respectively) remained largely effective. Binary, ternary or quaternary mixtures of Groups 4, 6, 12 and 27 herbicides reduced the frequency of high-level resistant populations to 7.1%, 3.8% or 0%, respectively. The cost-effective control of R. raphanistrum remains a challenge due to herbicide resistance. Raphanus raphanistrum management relies heavily on herbicide uses not yet compromised by resistance, such as pre-emergence herbicides (atrazine, fomesafen, mesotrione), glyphosate, and mixtures of two, three or four modes of action including bromoxynil, diflufenican, MCPA, picolinafen, pyrasulfotole and topramezone. Strategies that integrate effective herbicide use patterns, novel modes of action and efficiently-mechanized non-chemical weed control options (i.e., seed destructors) can completely constrain the selection of herbicide resistance in this highly adaptable species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessing the Efficacy and Safety of Preemergence Herbicides Applied Alone or in Combination with Superabsorbent Polymer, Soil Binding Agent, and Compost in Tomato (Solanum lycopersicum L.) Plasticulture Production

Preemergence herbicide application under plastic mulch is an effective way to manage weeds in tomato (Solanum lycopersicum L.) production. Nonetheless, applying herbicides beneath plastic mulch in raised beds is associated with the inherent risk of crop phytotoxicity. This highlights the need to explore crop-safe methods for herbicide application in plastic mulch beds. The research aimed to evaluate the effectiveness of preemergence herbicides S-metolachlor and flumioxazin at the labeled rate (X) and reduced rate (0.5X, half of the labeled rate) either alone or in combination with a super absorbent polymer, soil binding agent, or compost to determine their ability to control weeds effectively in plastic mulched beds without causing negative effects on tomato crops. Two different experimental trials, trial 1 (Mar–Jun 2021) and trial 2 (Oct 2021–Jan 2022) were performed in the fields in Immokalee, FL, USA. The experimental design was a randomized complete block with five replications. S-metolachlor (X) plus soil binding agent and S-metolachlor (X) plus compost mix suppressed purple nutsedge density by >85% and approximately 68%, respectively, during trial II. Similarly, S-metolachlor (X), S-metolachlor (0.5X) plus super absorbent polymer, S-metolachlor (X) plus super absorbent polymer, S-metolachlor (X) plus soil binding agent, and S-metolachlor (X) plus compost caused reductions in purple nutsedge biomass by >50% compared with that of the nontreated control during trial II. Treatments did not significantly impact tomato crop vigor and chlorophyll contents during trials I and II. Moreover, treatments did not significantly affect tomato crop biomass and yield during both trials. In summary, using preemergence S-metolachlor (X) combined with soil binding agent or compost could be a viable option for suppressing purple nutsedge in plastic mulched tomato beds.