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The demand for rice to meet the dietary need in low-income countries is expected to witness an exponential rise as the population increases. Meeting the rice demand domestically has remained challenging due to significant yield loss caused by several biotic and abiotic factors. Among these factors, one of the most important is the high weed pressure that ravages the upland rice ecology. In Nigeria, several independent weed control techniques, such as physical, chemical and cultural methods, have been recommended and adopted for weed control across varying rice upland ecologies. However, outcomes of these approaches when used independently have not consistently led to an increase in yield. There remains an outstanding deficit between the actual yield and the potential rice yield. This review aimed to identify potential research gaps, and quest effective and sustainable weed management strategies in smallholder upland rice farming systems in Nigeria. A critical analysis of studies suggests the potential of sustainable weed management practices if adopted and adapted smartly in different upland ecologies in Nigeria. Competitiveness of upland rice against weeds can be enhanced through strategic integration of weed competitive cultivars, optimum nitrogen application timings (within weed-free periods), uniform plant spacing, and high seeding rates, with conventional herbicide/manual weed control practices. However, such management practices can only be engaged where inputs are supplied on time and the technical know-how is extended to farmers. The review equally highlights potential research gaps for further studies. [ABSTRACT FROM AUTHOR]

Due to the increasing number of herbicide-resistant weed populations and the resulting yield losses, weed control must be given high priority to ensure food security. Integrated weed management (IWM) strategies, including reduced herbicide application, sensor-guided mechanical weed control and combinations thereof are indispensable to achieve this goal. Therefore, this study examined combinations of pre- and post-emergence herbicide applications with sensor-based harrowing and hoeing in cereals by conducting five field experiments at two locations in Southwestern Germany from 2019 to 2021. Each experiment contained an untreated control and a single post-emergence herbicide treatment as a comparison to these IWM treatments. The effects of the different IWM approaches on weed control efficacy (WCE), crop density, and grain yield were recorded. All experiments were set up in a randomized complete block design with four repetitions. Pre-emergence herbicide application combined with one-time harrowing and subsequent hoeing (Pre-Herb + Harr + Hoe) achieved the highest WCE (100%), followed by an approach of WCE (95%) for two-times hoeing. In contrast, a single pre-emergence herbicide application achieved the worst result with an average WCE of 25%. Grain yield was equal between all treatments in between 6 t ha−1 and 10 t ha−1, except for a single pre-emergence herbicide application, which achieved a 2.5 t ha−1 higher grain yield in winter wheat in 2021 that averaged 11 t ha−1, compared to the combination of Pre-Herb + Harr + Hoe that averaged 8.5 t ha−1. The results showed that it is possible to reduce and replace herbicides while achieving equivalent yield and WCE. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is grown in a wide range of agro‐ecological environments and production systems across Mexico. Weeds are a major constraint on maize grain yield, but knowledge regarding the best weed management methods is lacking. In many production systems, reducing tillage could lessen land degradation and production costs, but changes in tillage might require changes in weed management. This study evaluated weed dynamics and rainfed maize yield under five weed management treatments (pre‐emergence herbicide, post‐emergence herbicide, pre‐emergence + post‐emergence herbicide, manual weed control, and no control) and three tillage methods (conventional, minimum and zero tillage) in three agro‐ecologically distinct regions of the state of Oaxaca, Mexico, in 2016 and 2017. In the temperate Mixteca region, weeds reduced maize grain yields by as much as 92% and the long‐growing season required post‐emergence weed control, which gave significantly higher yields. In the hot, humid Papaloapan region, weeds reduced maize yields up to 63% and pre‐emergence weed control resulted in significantly higher yields than treatments with post‐emergence control only. In the semi‐arid Valles Centrales region, weeds reduced maize yields by as much as 65%, but weed management was not always effective in increasing maize yield or net profitability. The most effective weed management treatments tended to be similar for the three tillage systems at each site, although weed pressure and the potential yield reduction by weeds tended to be higher under zero tillage than minimum or conventional tillage. No single best option for weed management was found across sites or tillage systems. More research, in which non‐chemical methods should not be overlooked, is thus needed to determine the most effective weed management methods for the diverse maize production systems across Mexico. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Branched broomrape (Phelipanche ramosa), a parasitic weed that was the focus of a $1.5 million eradication effort four decades ago in California, has recently re-emerged in tomato fields in several Central Valley counties. Processing tomatoes are important to the California agricultural economy; the state produced over 90% of the 12 million tons of tomatoes grown in the United States in 2018. Branched broomrape is listed as an “A” noxious weed by the California Department of Food and Agriculture (CDFA); discovery of broomrape in California tomato fields leads to quarantine and crop destruction without harvest, resulting in significant economic loss to growers. In countries where broomrape is common, yield reductions caused by this parasitic weed can range from moderate to 80%, depending upon the infestation level, host and environmental conditions. Developing a detailed understanding of the biology of this weed under local conditions is an important step towards developing effective management plans for California. In this review, we discuss branched broomrape in the context of California production systems, particularly of tomato. We also discuss the potential management practices that could help to prevent or reduce the impacts of branched broomrape in tomatoes and other host crops.

Following growers’ reports of herbicide control problems, populations of 30 wild oats, Avena fatua, were collected from the south-east main arable counties of Ireland in 2016 and investigated for the occurrence and potential for herbicide resistance to acetyl-CoA carboxylase (ACCase) inhibitors pinoxaden, propaquizafop and cycloxydim, as well as acetolactate synthase (ALS) inhibitor mesosulfuron + iodosulfuron. Plant survival ≥20% was considered as the discriminating threshold between resistant and susceptible populations, when plants were treated with full recommended field rates of ACCase/ALS inhibitors. Glasshouse sensitivity screens revealed 2 out of 30 populations were cross-resistant to all three ACCase inhibitors. While three populations were cross-resistant to both pinoxaden and propaquizafop, and additionally, two populations were resistant to propaquizafop only. Different degree of resistance and cross-resistance between resistant populations suggest the involvement of either different point mutations or more than one resistance mechanism. Nevertheless, all populations including the seven ACCase-resistant populations were equally susceptible to ALS inhibitor. An integrated weed management (cultural/non-chemical control tactics and judicious use of herbicides) approach is strongly recommended to minimize the risk of herbicide resistance evolution.

This study aimed to assess the phytosociology of weeds as a function of different crop management technology levels in cassava production. Field experiments were conducted in Santa Maria (29°41′03″ S; 53°48′25″ W) and Itaqui (lat. 29°07′31″ S; long. 56°33′11″ W), Rio Grande do Sul, Brazil. Treatments consisted of three technology levels: low (postemergence weeding without basal dressing); medium (weeding performed at 7 and 40 days after planting and fertilization with 6.25, 25, and 25 kg⋅ha−1 of N, P, and K, respectively); and high (postemergence application of s-metolachlor; 1250 kg⋅ha−1 of lime and 12.5, 50, and 50 kg⋅ha−1 of N, P, and K, respectively). Weed frequency, density, relative abundance, and importance values were calculated for each location. Then, locations were compared using a dissimilarity matrix. Weed density and diversity decreased linearly as technology levels increased. The predominant weed species found in Itaqui and Santa Maria belong to the Poaceae family. Itaqui presented highest weed diversity among the locations. The genus Cyperus had the highest importance value index in Santa Maria. The use of S-metolachlor at the high technology level provided a lower frequency and lower diversity of weed species than did levels without chemical control in Itaqui and Santa Maria.

Introducción. El establecimiento de cultivos de cobertura como Crotalaria spectabilis es una práctica agroecológica con múltiples beneficios agronómicos y ambientales. Objetivos. Evaluar el efecto de 3 métodos de siembra de C. spectabilis en café en el control de malezas, acúmulo de nitrógeno y fijación de carbono. Además, determinar el periodo de espera entre el control de malezas y la siembra de C. spectabilis, y la tolerancia de C. spectabilis a herbicidas post emergentes. Materiales y métodos. El primer experimento se realizó en Orosi, Costa Rica, en el 2017. C. spectabilis fue sembrada mediante 3 métodos en medio de las hileras de siembra del café. El segundo experimento se realizó en un invernadero en Alajuela, en el 2018. Se aplicó glifosato, glufosinato de amonio y diquat sobre potes llenos con suelo. Luego de 0, 4 y 8 días se sembró C. spectabilis con y sin cobertura de suelo. En el tercer experimento se sembraron en potes semillas de C. spectabilis; cuando las plantas tenían 2, 3 y 4 hojas verdaderas se aplicó fluazifop-p-butil, cletodim y bentazona, asimismo las mezclas fluazifop-p-butil + bentazona y cletodim + bentazona. Resultados. En Orosi, todos los tratamientos lograron una reducción de cobertura de malezas menor al 26%, en comparación con el testigo. La tasa de crecimiento relativo de C. spectabilis fue baja y similar en las 3 metodologías de siembra. La acumulación de nitrógeno y la absorción de CO2 fue mayor en el tratamiento de hileras tapadas (81,46 kg.ha-1 N y 6,20 t.ha-1 CO2, respectivamente). En invernadero, no se observó un efecto negativo de ningún herbicida sobre la germinación ni el crecimiento de C. spectabilis. Conclusión. Debido a la competencia con las malezas, no fue posible establecer C. spectabilis como cobertura en café, sin embargo el uso de los herbicidas evaluados en invernadero permitieron controlar las malezas.

Abstract Brassica carinata A. Braun is a non‐edible, oilseed winter crop for biofuel production that can diversify crop rotations and improve integrated weed management. The research objective was to evaluate the influence of B. carinata on weed population dynamics in the southeastern United States cropping systems. B. carinata was grown after cotton (Gossypium hirsutum L.), peanut (Arachis hypogea L.), or a clean summer fallow, and winter weed pressure was modified with or without S‐metolachlor. The emergence of Lamium amplexicaule L. increased at least 40% after cotton or peanut in 2018–2019 and 50% after cotton in 2019–2020 compared to summer fallow. Stellaria media (L.) Vill. emergence was increased over threefold after peanut or cotton in 2019–2020. Senna obtusifolia (L.) H.S. Irwin & Barneby emergence after cotton was increased at least 43% during both experimental years, whereas Amaranthus hybridus L. emergence was increased over 50% after peanut in 2019–2020 compared to summer fallow. Even without S‐metolachlor, B. carinata reduced A. hybridus (>27%) and S. obtusifolia (>25%) emergence compared to weedy winter fallow. After B. carinata harvest, A. hybridus emergence was reduced >40% with or without S‐metolachlor compared to winter fallow in 2018–2019. Overall, B. carinata biomass was highest after peanut for both seasons. B. carinata seed yield did not differ among crop history treatments in the first season, whereas in 2019–2020, the yield was higher after peanut (2417 kg ha−1) or fallow (2520 kg ha−1) compared to cotton (1710 kg ha−1). Weed management treatments were not different for B. carinata biomass or yield in any year. The results indicate that B. carinata can enhance integrated weed management strategies at the rotational level for summer crops by reducing seed banks of summer weed species, in addition to its potential as a winter biofuel crop for the southeastern United States.

Pelargonic acid is the most successful natural herbicide and can contribute to reducing synthetic herbicides, but information on its efficacy is contrasting. Given its high cost, a reduction of the rate could facilitate the spread of the use of this herbicide. Two greenhouse and three field experiments were conducted to evaluate the herbicidal efficacy of different doses of pelargonic acid on several weeds (Abutilon theophrasti, Alopecurus myosuroides, Conyza sumatrensis, Lolium rigidum, Persicaria maculosa, Setaria pumila, Solanum nigrum). Results show that the efficacy of pelargonic acid is partial both in the greenhouse and field since the sensitivity of weed species is very variable, yet significant weed biomass reduction was observed in field application. Grass weeds, in particular A. myosuroides and L. rigidum, were less sensitive to pelargonic acid, with reduced and transient symptoms even at the highest doses. A large difference in sensitivity was also observed between dicots weeds, with P. oleracea, P. maculosa and A. theophrasti being less sensitive than C. sumatrensis and S. nigrum. The efficacy of pelargonic acid in field conditions depends on the botanical composition of weed flora and environmental conditions. Hot and dry conditions can promote leaf traits that decrease weed sensitivity by reducing herbicide penetration inside leaves. Despite its high cost, pelargonic acid can be a useful tool in an integrated multi-tactic strategy for sustainable weed management, while its use as a stand-alone tactic is less recommendable.

Weeds are the primary biotic constraint affecting sesame growth and production. Here, we applied EMS mutagenesis to an elite sesame cultivar and discovered a novel point mutation in the sesame SiALS gene conferring resistance to imidazolinone, a group of acetolactate-synthase (ALS)-inhibitors. The mutant line exhibited high resistance to imazamox, an ALS-inhibitor, with hybrid plants displaying an intermediate response. Field-based validation confirmed the mutant line's substantial resistance, leading to a significantly higher yield under imazamox treatment. Under pre-emergence application of imazapic, the mutant plants sustained growth, whereas wild-type and weed were effectively controlled. Field trials using s-metolachlor and imazapic combined resulted in weed-free plots compared to untreated controls. Consequently, this treatment showed a significantly greater yield (2280 vs. 880 Kg ha−1) than the commercial practice (s-metolachlor). Overall, our study unveils the potential of utilizing this point mutation in sesame breeding programs, offering new opportunities for integrated weed management strategies for sesame cultivation. Developing herbicide-resistant crop plants holds promise for supporting sustainable production and addressing the challenges of weed infestations in sesame farming. • A point mutation in the sesame SiALS gene conferring resistance to Imidazolinone. • Hybrid plants display an intermediate response. • The mutant plants sustained growth under pre-emergence application of Imazapic. • A new approach for integrated weed management in sesame was developed. • Developing herbicide-resistant crops can support sustainable food production. [ABSTRACT FROM AUTHOR]

Under intensive agriculture, weeds cause heavy losses in crop yield and quality. The existing manual method of weed control is no longer sustainable because of paucity of labours, higher wage, and huge drudgery. Herbicide is an easier, more efficacious, and economical tool for weed control in crops and un-cropped situations. However, the consequences of herbicide use, concerning non-target toxicities, and the evolution of herbicide-resistant weeds have drawn the attention of world communities. Therefore, in this review, we attempt to highlight the potential benefits vis-à-vis harmful consequences of herbicides in diversified crop ecologies across the world. Herbicide use resulted in weed control efficiency of 52–96% in different agro-ecologies. Besides, it could increase grain yield of different arable crops by 19–372% with an additional economic benefit of US$ 305 - US$ 867 over unweeded control. Chemical weed management resulted in gain in net returns by 4–12% over manual weeding (∼two hand weedings) and by 7–247% over the weed-free check in different countries. The majority of herbicides used at recommended doses in crops did not show any direct and/or residual toxicity on soil micro-organisms in agro-ecologies. Environmental conditions may change pesticide impacts on non-target micro-organisms. Over-reliance on herbicides and injudicious use at higher rates may lead to a fragile ecosystem, but judicious use can stimulate productivity, profitability and livelihood security. Hence, integrated weed management (IWM) that can restrict weed populations below threshold level, reduce environmental foot-print, increase cropping system sustainability, and reduce selection pressure for weed resistance to herbicides has been suggested. • Chemical weed management increased 4–12% returns and 52–96% efficacy over manual weeding. • Herbicides at recommended doses did not show any toxicity on soil micro-organisms. • Environmental conditions change impacts of herbicides on non-target microorganisms. • Over-reliance on herbicides and injudicious use may lead to a fragile ecosystem. • Integration of herbicides with suitable methods is recommended for environmental safety. [ABSTRACT FROM AUTHOR]

Although different modifications of ridge tillage (RT) systems exist in different regions around the world, the positive impacts of RT on crop yields and weed management are quite similar. This review gives a comprehensive summary of different forms of RT and highlights the benefits of RT for crop growth, mainly due to better access to soil moisture, nutrients and light. In temperate areas, RT can accelerate crop emergence because soil temperature is usually higher on the ridge. These stimulating effects increase crop competitiveness against weeds especially in the early period of crop development until canopy closure. RT with crops placed on the top of ridges can also be used for automatically guiding inter-row hoes and intra-row band sprayers. The ridges can replace automatic vision control systems for hoeing and band spraying, which are needed for precise weeding in conventional flat seedbeds. Therefore, RT can be considered a possible platform for smart/robotic weeding. This paper introduces a new RT system using real-time kinematic (RTK) global satellite navigation systems (GNSS) for the ridging and seeding of maize and soybean on top of recompacted ridges. Straight ridges with precise positioning data were used to guide mechanical weeding elements precisely along the crop rows. Simultaneously, weeds in the valleys were suppressed by living mulches. Field experiments with this new technology in maize showed 85.5% weed dry biomass suppression compared to an untreated control and a slightly higher weed control efficacy than mechanical weeding in flat seedbeds. [ABSTRACT FROM AUTHOR]

Herbicide-resistant weeds are a growing challenge in agricultural systems worldwide, leading to additional management costs and yield losses. Best practice management guidelines have been promoted for decades, yet incidences of resistance continue to increase. In New Zealand, herbicide resistance might be more widespread than commonly assumed. To respond to the emerging challenge, this article draws on qualitative social research with arable farmers and agricultural stakeholders in the Canterbury region to describe drivers underlying herbicide use on three levels: individuals' psycho-social context, farm system characteristics, and the socioeconomic system. While findings show concerns for maintaining practical and profitable farm operations, we argue that farmers' herbicide use is influenced by diverse biophysical, technological, and sociocultural factors, with some hindering recommended best practice. These findings demonstrate that integrated systems-based approaches are needed to holistically understand herbicide use as a critical step in collaborative efforts to establish feasible practice guidelines and management strategies. [ABSTRACT FROM AUTHOR]

Amongst all biotic factors, weeds pose the most serious threat to successful cotton production. Adoption of conservation agriculture, the evolution of herbicide-resistant weed populations, and the absence of any new herbicide chemistry are allowing weeds to become more destructive and uncontrollable. It is important now to investigate cultural practices (non-chemical) to reduce the pressure on herbicides. Trials were conducted at the Gatton Research Farm of University of Queensland during 2015/16 and 2016/17 to assess the implications of narrow row-spacing (50 cm) in managing weeds in glyphosate-tolerant cotton at different weed-infestation intervals [0, 21, 42, 63, 84 and 154 days after planting (DAP)]. Results revealed that narrow (50 cm) row-spacing (at the same density of planting) was not only beneficial in suppressing weed growth (55% lower) and achieving greater lint yield (26% more) but also made the cotton plants more competitive in the early weed-crop interference compared with wide (100 cm) row-spacing. Consequently, the weed-crop competition period (CWIP) was shorter (42 days after emergence) in narrow row-spaced cotton when compared with wide row-spaced cotton (154 days after emergence). The use of this technology will reduce the reliance on herbicides, which in turn will decrease the development of future herbicide-resistant weed populations. [ABSTRACT FROM AUTHOR]

Vegetables are consequently experiencing great yield losses due to weed infestation. Weed management is extremely important for sustainable crop production in all cropping systems. This review paper aimed to provide general information and alternative recommendations for the management of Parthenium hysterophorus weed by chemicals, adjuvants and plant extracts in okra. Different strategies have been used to control parthenium, but no single management solution is sufficient to handle parthenium; hence, different management options need to be combined. Only an integrated approach will achieve effective control over this weed. In areas where parthenium natural enemies are absent, chemical control is an important method of managing this weed. In the control of this plant, the use of chemical herbicides such as chlorimuron ethyl, glyphosate, atrazine, ametryn, bromoxynil and metsulfuron are considered to be efficient. Moreover, various plants have allelopathic potential and attempts have been made to use them in parthenium control. Three allelopathic grasses, namely, Achyranthes aspera, Syzygium cumini and Acacia nilotica are able to minimize the plant growth and inhibit early seedling growth of exotic weed P. hysterophorus. The results recommend that the control of parthenium in okra and other summer vegetables using chemical herbicides with single and combination mode of action is still effective compared to the use of plant extracts. The use of herbicides by adding adjuvants has the potential to minimize the use of excessive herbicides.

Cinmethylin is a potential new pre-emergence herbicide in Europe inhibiting the fatty acid thioesterases in the plastid against Alopecurus myosuroides and other grass-weeds in winter cereals and oil-seed rape. Five field experiments were conducted in Southwestern Germany from 2018 until 2020 to assess the control efficacy of cinmethylin and other common pre-emergence herbicides alone and combined with post-emergence herbicides against A. myosuroides and yield response of winter wheat and winter triticale. In four experiments, the effect of early and late sowing of winter cereals was included as the second factor in the experiment to investigate if late sowing can reduce A. myosuroides density weed control efficacy. All fields were heavily infested with A. myosuroides with average densities of 110-730 plants/m2. Late sowing reduced densities in three out of four experiments. Herbicides controlled 42-100% of the A. myosuroides plants. However, none of the treatments was consistently better than the other treatments over all experiments. In three out of 5 experiments, grain yields were significantly increased by the herbicide treatments. The results demonstrate that cinmethylin increases the options for controlling A. myosuroides in winter cereals. However, it needs to be combined with other control tactics.

This study evaluated false seedbeds, which are sequences of irrigation and tillage that eliminate weed seedlings before crop planting, to reduce requirements for hand hoeing in chile pepper (Capsicum annuum). To address this objective, a field study was conducted near Las Cruces, NM from July 2015 to Oct. 2016 (experimental run 1) and July 2016 to Oct. 2017 (experimental run 2). False seedbeds were designed to target weeds that typically emerge after chile pepper planting. This was done by implementing false seedbeds the summer before chile pepper seeding. During chile pepper seasons, data included repeated measures of weed seedling emergence, amounts of time required for individuals to hoe field sections (i.e., hoeing time), and yields of two chile products: early harvest of green fruit and late harvest of red fruit. Hoeing time and yield data were included in cost–benefit analyses that also incorporated expenses and revenues projected by crop budget models for the study region. Results indicated false seedbeds caused a 54% decrease in weed population density during the chile pepper season of experimental run 1; however, for experimental run 2, false seedbeds did not affect cumulative weed seedling emergence. For both experimental runs, false seedbeds reduced hoeing times, suggesting that false seedbeds affected hoeing by means other than reduced weed density. After accounting for costs for implementation, false seedbeds reduced hand hoeing costs by $262/acre to $440/acre. These reductions in hoeing costs coincided with improved profitability in all but one combination of year and product. Green fruit yield was lower in false seedbed plots in experimental run 1; however, false seedbeds did not affect green fruit yield in experimental run 2, or red fruit yield in both experimental runs. These results indicate that false seedbeds implemented the summer before planting are promising techniques for reducing labor requirements for weeding in chile pepper production.

Corn- and soybean-dominated cropping systems create and maintain a favorable environment for summer annual weeds whose emergence and growth phenology are similar to these annual summer crops. Cropping system diversification can be an effective approach for controlling noxious weeds without increasing reliance on chemical herbicides. Diversification may be especially important for managing waterhemp, a dioecious, summer annual weed that is becoming increasingly prevalent in the US Corn Belt due to its life history characteristics and herbicide resistance profile. Compared to corn and soybean, alfalfa and oat emerge and establish earlier and are thus more competitive with warm-season weeds like waterhemp. Knowledge of vegetative and reproductive characteristics in a range of crop environments can be valuable for planning weed management strategies. However, most of the relevant characteristics for a population dynamics model were available in corn and soybean monocultures. We examined the relationship between waterhemp's aboveground mass and fecundity under four crop species' presence within three crop rotation systems: a 2-year sequence of corn and soybean; a 3-year sequence of corn, soybean, and oat intercropped with red clover; and a 4-year sequence of corn, soybean, oat intercropped with alfalfa, and alfalfa. All the rotation systems were treated with conventional or reduced rates of herbicides. We established eighteen linear equations to predict waterhemp's fecundity from dried aboveground mass in each crop and associated crop management program since measuring the latter allows for quicker estimation of fecundity compared to counting seeds on each individual plant. Rotation system and crop phase within rotation system had significant effects on all the response variables but weed control regime on some. The sex ratios at maturity were slightly female-biased in oat and alfalfa. Mature waterhemp plants were larger in corn and soybean than in oat and alfalfa. Oat and alfalfa were planted earlier than corn and soybean and successfully competed for resources against waterhemp despite the absence of herbicide or interrow cultivation. Frequent hay cuts in alfalfa served as physical weed control and contributed to suppressing waterhemp and other weeds substantially.

Weed control is necessary to ensure a high crop yield with good quality. Herbicide application and mechanical weeding are the most common methods worldwide. The use of herbicides has led to the increasing occurrence of herbicide-resistant weeds and unwanted contamination of the environment. Mechanical weed control harms beneficial organisms, increases the degradation of organic matter, may dry out the soil, and stimulate new cohorts of weed seeds to germinate. Therefore, there is a need to develop more sustainable weed control means. We suggest using small autonomous vehicles equipped with lasers as a sustainable alternative method. Laser beams are based on electricity, which can be produced from non-fossil fuels. Deep learning methods can be used to locate and identify weed and crop plants for targeting and delivery of laser energy with robotic actuators. Given the targeted nature of laser beams, the area exposed for weed control can be reduced substantially compared to commonly used weed control methods. Therefore, the risk of affecting non-target organisms is minimized, and the soil will be kept untouched in the field, avoiding triggering weed seeds to germinate. Small autonomous vehicles may have limited weeding capacity, and precautions need to be taken as reflections from the laser beam can be harmful to humans and animals. In this paper, we discuss the pros and cons of replacing or supplementing common used weed control methods with laser weeding. The ability to use laser weeding technology is relatively new and not yet widely practiced or commercially available. Therefore, we do not discuss and compare the costs of the various methods at this early stage of the development of the technology.

A two-year study was conducted on integrated weed management in maize under different tillage regimes at Agricultural Research Station Swabi Khyber Pakhtunkhwa, Pakistan during Spring 2014 and subsequently repeated in 2015. The experiment was laid out at silt loam soil in Randomized complete block design (RCBD) with a split plot arrangement having three replications. Tillage regimes ((minimum, conventional and deep tillage) were kept in main plots (Factor A) and allelopathic plant residues (sorghum, sunflower and parthenium) as surface mulched in various combinations and their water extracts @ 15L each + atrazine @ ?th of recommended dose were assigned to the sub-plots (Factor B), for weed management in maize. Data during both years (2014 and 2015) were recorded and analyzed for dry biomass of weeds 30 DAS, kernels ear-1, ear length (cm), kernel yield (kg ha-1) and cost benefit ratio. Foliar application of Sorghum + parthenium water extracts at 15 L integrated with a quarter recommended dose of atrazine (pre emergence) under conventional tillage regimes suppressed total weed dry biomass by 34 and 42% at 30 DAS during 2014 and 2015, respectively which increased maize kernel yield by 52 % over the weedy check and was almost equivalent to the label dose of atrazine (0.50 kg a.i ha-1) and also had the highest CBR (1:20.4). Among the soil mulch treatments, Sorghum + sunflower +parthenium each at 4 Mg ha-1 under deep tillage regimes suppressed weed dry biomass by 69 and 75 % at 30 DAS during 2014 and 2015 respectively, pooled data of both years (2014 and 2015) indicated increase in maize kernel yield by 54 % over control with CBR (1:15:2). However, the mulch treatments and the cost of deep tillage were uneconomical. Hand weeding under deep tillage regimes increased maize kernel yield by 46 % as compared to the weedy check. Based on current studies, it is concluded that foliar application of Sorghum + parthenium aqueous extract integrated with reduced atrazine dose are economical and eco-friendly having the highest CBR. Consequently, reliance on atrazine could be reduced by 75% resulting in environmental safety and sustainability, however further studies are suggested to fine tune our findings. [ABSTRACT FROM AUTHOR]

Winter cover crops (CC) may facilitate weed management by inhibiting weed seed germination and seedling emergence and suppressing weed growth within the cash crop. In southern New Mexico, with scarce winter precipitation and limited irrigation water, producing sufficient CC biomass for effective weed suppression while conserving water resources is challenging. This study assessed the water requirement to produce a CC with enough biomass for weed suppression benefits during cash crop growth at two locations in New Mexico. Three winter CC species, barley, Austrian winter pea and mustard, grown singly and in a three‐way mix, under three differential irrigation treatments (one, two or three irrigations after emergence) were evaluated for their weed‐suppressive potential. Maize was planted as a cash crop four weeks after winter CC termination. Number of irrigations had no effect on the CC and weed biomass production. All CCs had lower weed density prior to maize planting compared with fallow. Barley and the three‐way mix reduced weed density by 56–96% and 68–95%, respectively. All CC treatments had lower weed biomass at the end of critical period for weed control in maize compared with fallow. Weed biomass at maize harvest did not differ between treatments. The maize yield was consistently higher in conventionally managed, weed‐free subplots, than in unsprayed weedy subplots, suggesting that CCs did not suppress weeds throughout the maize growing season. Except for barley, CCs did not cause reductions in maize yield compared with fallow. Overall, the study suggested that with adequate winter precipitation, weed‐suppressive winter cover crop stands can be produced with just one irrigation at seeding and one supplemental irrigation, making them a viable option in water‐limited agroecosystems. [ABSTRACT FROM AUTHOR]

A living mulch is a cover crop grown during the growing season of a main (cash) crop. Living mulches may reduce soil erosion and nitrate leaching more effectively than bare ground or non‐living mulches. Living mulches can also make substantial contributions to non‐chemical or diversified weed management programmes. However, living mulches sometimes fail to suppress weeds, or they succeed at the cost of main crop yield. Seeking to understand these divergent outcomes, we survey the effects of living mulches on weeds in temperate field and vegetable crops. Primary purposes of this review include (a) outlining mechanisms of weed control by living mulches, (b) identifying major sources of variation in weed control outcomes, and (c) highlighting knowledge gaps. The effects of living mulches on weeds are largely (but not exclusively) via competition and typically strongest when living mulch vigour is high at sensitive stages of weed life cycles. Best management practices depend on living mulch, main crop, and weed community characteristics. Living mulches often have different effects on different weed species, which may have far‐reaching consequences for weed diversity and community composition. Future research on long‐term changes to weed communities will clarify how and when living mulches should be adopted to increase agroecosystem biodiversity and promote sustainability. [ABSTRACT FROM AUTHOR]

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Determination of interference periods, competitive ability and economic threshold level (ETL) are important tools for integrated weed management (IWM) in barley. The objective of the work was to determine the periods of interference, the competitive ability and the ETL of weeds in barley (Hordeum vulgare). Two field experiments were carried out, in a randomized block design, with four replications. In this study, the periods of coexistence and control for ryegrass (Lolium multiflorum) and turnip (Raphanus raphanistrum) infesting barley cultivar, cv. ANA 01 were evaluated. The coexistence periods and/or control were: 0, 7, 14, 21, 28, 35, 42 and 120 days after barley emergence (DAE). In experiment 2the treatments for determination of ETLs were composed by barley cultivars (BRS Suábia, ANA 01, BRS Korbel, BRS Manduri, BRS Cauê and BRS Greta), and turnip densities, from zero (0) to maximum densities of 816, 788, 948, 394, 584 and 618 plants · m−2, in competition with each cultivar. Control of turnip and ryegrass should be adopted in barley in the period between 12 to 22 DAE, which is described as a critical control period. The rectangular hyperbola adequately estimates losses in grain yield due to turnip infestation. There is an effect on the competitive ability of the cultivars in relation to turnip, which resulted in ETLs that ranged from 0.27 to 1.99 plants · m−2 . The cultivars BRS Greta, BRS Suábia, ANA 01 and BRS Manduri were the most competitive in the presence of turnip. [ABSTRACT FROM AUTHOR]

Weed infestation is one of the main challenges in crop management. The environmental, economic and social impacts attributed to pesticides lead to the search for new sustainable possibilities for the management of these plants, especially for Commelina benghalensis, which is considered one of the worst weeds in the world. This work consists of a description of the external morphology of the insect Lema quadrivittata and its potential use as a biological regulator of C. benghalensis, a weed plant, which suffers effective injuries by this natural enemy. Plots with high infestation of C. benghalensis were inspected to find plant damage and its possible causes. Upon identifying the occurrence of L. quadrivittata, it was decided to cultivate C. benghalensis in a greenhouse in order to observe the interaction of the insect with the plant. In this sense, during the study, we identified the insect L. quadrivittata by describing its morphological structures of adults and larvae and its interaction with C. benghalensis as a biological control agent. This work is an approach to the attack of L. quadrivittata on C. benghalensis. Future studies are needed to indicate the potential of this insect as a biological regulator of this weed from the knowledge of its behavior, morphology and evaluations of potential hosts. [ABSTRACT FROM AUTHOR]

Weeds are a major problem in potato production. Two years of trials were conducted to study the efficacy of herbicides and integrated use of mulch with herbicides in controlling weeds and for improving the growth and yield of autumn potato crop at Ludhiana, north-west India, during autumn 2016 and 2017. Each trial had a randomized complete block design with three replicates. There were 11 treatments including weed-free and weedy controls. Uncontrolled weeds caused a yield reduction of 49.7%. Metribuzin at 350 g/ha pre-emergence resulted in 82.4% weed control efficiency at 30 days after planting but this control was reduced to 23.9% at harvest. In contrast, metribuzin at 350 g/ha applied post-emergence controlled broadleaf weeds and grasses very effectively. Clodinafop at 60 g/ha post-emergence resulted in control of grasses only. The post-emergence application of pre-mix clodinafop plus metribuzin at 260 g/ha provided effective weed control and resulted in more tuber yield and economic returns and was significantly better than an application solely of metribuzin or clodinafop. The integrated weed control treatment of paddy straw mulch (PSM) at 6 t/ha with clodinafop plus metribuzin at 195 g/ha post-emergence resulted in the highest tuber yield with weed control efficiency of 95.3% at harvest. The next best one was an integrated treatment of PSM at 6 t/ha with metribuzin at 275 g/ha pre-emergence. [ABSTRACT FROM AUTHOR]

Weed infestation is considered a significant yield reducing factor in maize yield around the world as well as in the south Asia. Integrated weed management (IWM) is recommended to reduce our reliance on synthetic herbicides and sustainable maize production. In this study, different tillage regimes and various allelopathic treatments were integrated for weed management in spring planted maize at Agricultural Research Station, Swabi (KP), Pakistan during spring both years 2014 and 2015. The experiment was laid out at silt loam soil in Randomized Complete Block Design (RCBD) with a split plot arrangement having three (03) replications. Different tillage regimes namely minimum, conventional, and deep tillage regimes were assigned to main plots (Factor A) and various allelopathic plants [Sorghum {Sorghum bicolor (L.) Conard Moench.}, Sunflower (Helianthus annuus L.) and Parthenium (Parthenium hysterophorus L.)] residues as surface mulches and their water extracts integrated @ 15L each +atrazine @ 0.125 kg a.i ha-1(1/4th of the recommended dose) was assigned to sub plots (Factor B). Data were recorded and analyzed for dry biomass (g) of total weeds 60 DAS, leaf area (cm²), leaf area Index (%) and Stover yield (Kg.ha-1). Integration of tillage regimes and various allelopathic treatments had significant effect on tested parameters. However, the efficacy of surface mulches was more pronounced than atrazine foliar application @ 0.50 kg a.i ha-1 and allelopathic plants water extracts combined with atrazine @ 0.125 kg a.i ha-1. Data obtained for the interaction effect (tillage x weed control treatments) showed that maximum stover yield of 12426 kg.ha-1 was recorded in sorghum +sunflower + parthenium (S.M) each @ 6 Mg ha-1 at 3-4 leaf stage of maize under conventional tillage regime. Hence it could be considered as an alternative to atrazine @ 0.50 kg a.i ha-1 (recommended dose) for weed management in spring planted maize. However, further studies are suggested to investigate the phytotoxic effect of these plants' residues on soil microbial activities. [ABSTRACT FROM AUTHOR]

Rice is one of the most important crops for food security in Africa. However, there is a large gap between its present demand and supply. Weed competition is basically one of the major constraints in rice systems in Africa, leading to 48–100% yield reduction and sometimes complete crop failure, thereby threatening food security. Weed control methods currently employed to avoid such losses are predominantly hoe-weeding and herbicide application. Hoe weeding is tedious, inefficient, time consuming, associated with high labour demands and often too expensive for the average farmer to afford. Herbicide use on the other hand, does not provide season-long weed control. Moreover, there are not many herbicides that can control different kinds of weeds with one application. Thus, to optimise yield, financial, social and environmental costs and benefits, integrated and ecological weed management approaches are advocated. Future weed research should therefore be focused on delivering information for the implementation of these approaches. This would require improved knowledge of weed biology and ecology, prioritization of problematic weed species, development of competitive rice cultivars and timely weed control. To address the diversity of weed problems in rice systems in Africa, however, research innovations must take full account of farmer’s local conditions using farmers’ participatory approaches. This review suggests that knowledge-based integrated novel approaches must be developed to assist farmers in coping with the challenges of weed management for sustainable rice production.

ABSTRACT Weed management consists of a fundamental practice in cassava, with mechanical and chemical control widely used. The objective of this work was to evaluate the efficacy of pre-emergence herbicides, as well as to determine the interaction of these with weeding complementation in the weed management in cassava. Two experiments were conducted in Junqueiro (Alagoas). In 2015/16, the experimental design was based on randomized blocks, with treatments distributed in a split-split-plot scheme, with four replications. In the main plot, four pre-emergence associations of clomazone + flumioxazin in different doses were evaluated, in addition to a control without herbicide. In the subplots, the Caravela and Pretinha cassava cultivars were evaluated, while in the sub-subplots the control complementation was evaluated using or not the manual weeding. In the 2016/17, the plot design and layout remained the same as for 2015/16, except for the composition of the herbicide treatments, since the standardization of clomazone dose has been chosen, varying only the doses of flumioxazin. The association of clomazone and flumioxazin has shown efficacy in weed control, with a greater residual as higher doses are used. This association provided higher shoot and root yield. Weeding complementation along the cassava cycle can increase its yield.

The need to determine the minimum application rates of commonly used herbicides in Malete and the Guinea savanna of Nigeria for effective weed control and higher grain yield of maize, triggered this study. Therefore, field trials were conducted at the Teaching and Research Farm of Kwara State University, Malete, to determine the weed control method that will be more effective in controlling weeds and give higher grain yield and cash returns in the production of maize. The experiment consisted of 9 treatments viz: primextra (metolachlor plus atrazine) + 2,4-D at 1.5 + 1.5 kg active ingredient (a.i.).ha−1, primextra + 2,4-D at 2.0 + 2.0 kg a.i. ha−1, primextra + 2,4-D at 2.5 + 2.5 kg ha−1, primextra + nicosulfuron at 1.5 + 0.03 kg a.i. ha−1, primextra + nicosulfuron at 2.0 + 0.05 kg a.i. ha−1, primextra + niconsulfuron at 2.5 + 0.07 kg a.i. ha−1, primextra at 1.5 kg a.i. ha−1 + one Supplementary Hoe Weeding (SHW) at 6 Weeks After Sowing (WAS), two hand weeding at 3 and 6 Weeks After Sowing (WAS) and a weedy check. These treatments were laid out in randomised complete block design (RCBD) with three replicates. Data collected were subjected to analysis of variance using Statistical Analysis Software (SAS) package, after which means were separated using Duncan’s Multiple Range Test (DMRT). Results showed that treatment combinations of primextra + one SHW at 6 WAS, two hoe weeding at 3 and 6 WAS, primextra + 2,4-D at 2.0 + 2.0 kg a.i. ha−1 and primextra + nicosulfuron at 2.0+0.05 kg a.i. ha−1 gave effective weed control, higher grain yield and cash returns. Therefore, primextra at 1.5 kg a.i. ha−1 + one SHW at 6 WAS, primextra +2,4-D at 2.0 + 2.0 kg a.i. ha−1 and primextra + nicosulfuron at 2.0 + 0.05 kg a.i. ha−1 are recommended to farmers as alternative to two hoe weeding at 3 and 6 WAS.

Unter Berücksichtigung der allgemeinen Grundsätze des Integrierten Pflanzenschutzes (Richtlinie 2009/128/EG Anhang III) wurde im Rahmen eines dreijährigen europäischen ERA-Net-Projektes (Co-ordinated Integrated Pest Management in Europe - C-IPM) ein Internet-gestütztes Entscheidungshilfemodell für die Unkrautbekämpfung in Winterweizen und Mais entwickelt (DSS-IWM). Der Prototyp dieses DSS-Modells, IPMwise, wurde Rahmen des Projektes in drei europäischen Ländern erarbeitet, geprüft und verbessert. Die Behandlungsvorschläge des Programms richten sich nach der aktuellen Verunkrautung der Fläche und beruhen auf Dosis-Wirkungsdaten und spezifischen Ziel-Wirksamkeiten. Das Programm soll sowohl Landwirte als auch Berater verlässlich dabei unterstützen, Unkräuter zum richtigen Zeitpunkt mit den geeignetsten Herbiziden in optimierter Aufwandmenge zu bekämpfen und somit dazu beitragen, den Herbizidaufwand zu reduzieren, ohne Ertragseinbußen zu riskieren. In die Entscheidungen werden lokale Bedingungen, Schadensschwellen und ökonomische Berechnungen der Behandlungen einbezogen. Das Programm soll zukünftig auch als Tablet- oder Smartphone-Version dem Anwender zur Verfügung stehen. Validierungsversuche an verschiedenen Standorten in Deutschland zeigten, dass Wirkungsgrade sowohl im Mais als auch im Winterweizen nach Behandlungsvorschlägen des DSS-Programms im Mittel etwas niedriger waren als nach der lokalen Standardbehandlung, an einzelnen Standorten aber gleich hoch. Der Behandlungsindex in wurde in den DSS-Varianten bis zu 50 % verringert, wodurch Kosteneinsparungen für Herbizide von 50 % bis 60 % möglich waren. Das Programm ist demnach geeignet, um ökologische und ökonomische Ziele der Unkrautregulierung im Rahmen der Integrierten Unkrautbekämpfung zu fördern.

Weed infestation and inherent low soil fertility are among the major factors attributed to the low yield of rice in Nigeria. Field trials were therefore conducted to evaluate the effect of nitrogen application levels and weed control methods on growth and yield of upland rice (var. NERICA 2) at the Teaching and Research Farm of the Federal University of Agriculture, Abeokuta (07° 15'N, 03° 25'E) during 2015 and 2016 cropping seasons. Three nitrogen (N) levels (0, 60 and 90 kg/ha) were evaluated and they constituted the main plot treatments, while three weed control treatments, viz: pre-emergence application of Orizo Plus® (propanil plus 2, 4-D) at 2.0 kg a.i ha-1, Orizo Plus® at 2.0 kg a.i ha-1 followed by supplementary hoe weeding (SHW) at 6 weeks after sowing (WAS) and three hoe-weeding regimes at 3, 6 and 9 WAS, and a weedy check constituted the sub-plot treatments. All the treatments in different combinations were laid out in a randomized complete block design with a split-plot arrangement with three replicates. Results indicated a significant (p≤0.05) increase in weed density and dry matter with an increase in N application level from 0 to 90 kg ha-1. Similarly, crop vigour and plant height increased significantly (p≤0.05) with increasing N application levels up to 90 kg ha-1. However, 60 and 90 kg N ha-1 were at par in increasing the number of tillers, leaf area index and yield attributes of rice. All the weed control methods resulted in a significant (p≤0.05) reduction in weed density and dry matter with subsequent increase in rice growth and yield than the weedy check. Pre-emergence application of Orizo Plus® followed by SHW at 6 WAS and three hoe-weeding regimes resulted in significantly (p≤0.05) lower weed density and dry matter, and a higher number of tillers, panicle weight and grain yield than a sole application of Orizo Plus®. With Orizo Plus® followed by one SHW or three hoe-weeding regimes, increasing N application levels resulted in a significant (p≤0.05) increase in grain yield of rice. However, with Orizo Plus® applied alone, increasing N application levels did not increase rice grain yield. These results suggest that Orizo Plus® at 2.0 kg a.iha-1 followed by one SHW at 6 WAS integrated with N application at 90 kg ha-1 is adequate to effectively control weeds and increase rice yield in the rainforest-savannah transition zone of Nigeria.

Field trials were conducted at the Teaching and Research Farm of Kwara State University, Malete, to determine the weed control method that will be more effective in controlling weeds and give higher grain yield and cash returns in the production of maize. The experiment consisted of 9 treatments: Primextra + Aminicome at 1.5 + 1.5 kg ha-1 (metolachlor 375 g A.I. ha-1 + atrazine 375 g A.I. ha-1 + 2,4-D 900 g A.I. ha-1), Primextra + Aminicome at 2.0 + 2.0 kg ha-1 (metolachlor 500 g A.I. ha-1 + atrazine 500 g A.I. ha-1 + 2,4-D 1200 g A.I. ha-1), Primextra + Aminicome at 2.5 + 2.5 kg ha-1 (metolachlor 750 g A.I. ha-1 + atrazine 750 g A.I. ha-1 + 2,4-D 1500 g A.I. ha-1), Primextra + Guard force at 1.5 + 0.03 kg ha-1 (metolachlor 375 g A.I. ha-1 + atrazine 375 g A.I. ha-1 + nicosulfuron 1.2 g A.I. ha-1), Primextra + Guard force at 2.0 + 0.05 kg ha-1 (metolachlor 500 g A.I. ha-1 + atrazine 500 g A.I. ha-1 + nicosulfuron 2.0 g A.I. ha-1), Primextra + Guard force at 2.5 + 0.07 kg ha-1 (metolachlor 750 g A.I. ha-1 + atrazine 750 g A.I. ha-1 + nicosulfuron 2.8 g A.I. ha-1), Primextra at 1.5 kg ha-1 (metolachlor 375 g A.I. ha-1 + atrazine 375 g A.I. ha-1) + one supplementary hoe weeding (SHW) at 6 weeks after sowing (WAS), two hand weedings at 3 and 6 weeks after sowing (WAS) and a weedy check. These treatments were laid out in a randomized complete block design (RCBD) with three replicates. Data collected were subjected to analysis of variance using the Statistical Analysis Software (SAS) package, after which means were separated using Duncan's Multiple Range Test (DMRT). Results showed that treatment combinations of Primextra at 1.5 Kg ha-1 + one SHW at 6 WAS, two hoe weedings at 3 and 6 WAS, Primextra + Aminicome at 2.0 + 2.0 kg ha-1 and Primextra + Guard force at 2.0 + 0.05 kg ha-1 gave effective weed control, higher grain yield and cash returns. They are therefore recommended for application in rotation by farmers in Malete.

Milk thistle besides being a highly competitive weed is cultivated as a medicinal plant, and the seeds of which have been clinically utilized in several disorders caused in liver. The present study aims to evaluate the effect of duration and storage conditions, population, and temperature on seed germination. The experiment was conducted in Petri dishes with three replications and three factors: (a) wild populations of milk thistle (Palaionterveno, Mesopotamia, and Spata) originating from Greece, (b) duration and storage conditions (5 months at room temperature, 17 months at room temperature, and 29 months in the freezer at −18 °C), and (c) temperature (5 °C, 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C). All three factors significantly affected germination percentage (GP), mean germination time (MGT), germination index (GI), radicle length (RL), and hypocotyl length (HL) and significant interactions among the treatments were noted. In specific, no seed germination was recorded at 5 °C, while the populations showed higher GP and GI at 20 °C and 25 °C after 5 months of storage. Prolonged storage negatively affected seed germination although, cold storage mitigated this effect. Moreover, higher temperatures reduced MGT and increased RL and HL with the populations reacting differently in storage and temperature regimes. The results of this study should be taken into consideration when proposing the appropriate sowing date and storage conditions of the seeds used as propagation material for crop establishment. Moreover, the effects of low temperatures such as 5 °C or 10 °C on seed germination as well as the high decline rate in germination percentage over time could be utilized in the design of integrated weed management systems thereby indicating the importance of the sowing time and the suitable crop rotation system to weed control.

Modern vegetable production systems are often characterized by monoculture fields and the intensive use of tillage and/or synthetic agrochemicals for managing weeds. A growing public interest in more sustainable and eco-friendly production practices has resulted in increased demand for crops to be produced with lower inputs. Field studies were conducted over three field seasons to investigate the use of conservation tillage in concert with an interplanted living mulch and/or cover crop residue for managing weeds in sweet corn as compared with the standard practice of using conventional tillage and pre-emergence residual herbicides. Whole plot treatments included: (1) conventional till, (2) no-till with cover crop residue, (3) living mulch + cover crop residue, and (4) living mulch + winter killed residue. The split-plot factor consisted of herbicide treatments: (1) at-planting application of residual herbicides or (2) no herbicide. The cover crop systems suppressed weeds as well as the standard practice throughout the cropping cycle in all three years. In addition, there was no significant improvement in weed suppression with the application of herbicides within the cover crop treatments. Crop development and yield were similar among treatments in year 2. However, reduced yields were encountered in all cover crop treatments during year 3 relative to the conventional tillage treatment.

Weeds are the major biological constraints to wheat production, which reduces the wheat yield up to 80%. The phytotoxic effect of brassica water extracts against weeds has been previously studied; however, the effects of mustard seed meal water extract (MSMWE) alone or in combination with reduced rate of isoproturon (IP) have not yet been explored. Hence, a field experiment was conducted in randomized complete block design to investigate the efficacy of MSMWE, at variable rates, i.e., 113, 225, 338, and 450 L ha−1 alone or combined with IP at 0.50 kg a.i. ha−1 (POST) (IP 0.5), and compared with the recommended rate of IP at 1.0 kg a.i. ha−1 (POST) (IP 1.0), weedy control, and twice-hand weeding (2-HW). Results revealed that 2-HW was the best treatment for weed suppression and wheat yield. Overall, MSMWE 450 L ha−1 + IP 0.5 was highly effective in the suppression of broadleaved weeds (BLWs) as well as of total weeds, and recorded the highest weed control efficiency (47.67) and herbicide efficiency index (0.927). Further, this treatment positively enhanced the tiller count, grain count earhead−1 and grain yield. Application of IP 1.0 effectively suppressed the BLWs, however, failed in the suppression of grassy weeds and total weeds; further, it showed a negative influence on crop dry matter accumulation and grain yield. Sole application of MSMWE suppressed the grassy weeds, dominated by Cynodon dactylon, as compared to combined and sole application of IP. Here we show for the first time that sole MSMWE has potential for suppression of C. dactylon.

The increased demand for the adoption of sustainable practices to protect agroecosystems is challenged by the introduction and dominance of invasive plant species (IPS). The management of IPS requires a direct response from farmers and policy makers and is often associated with the adoption of practices that have negative ecological impacts. Solanum elaeagnifolium Cav. (silverleaf nightshade) is a noxious IPS posing a serious threat to agriculture and the environment. The increased resistance to the biotic and abiotic stress factors caused by high phenotypic plasticity, dense trichomes, and spines allow the weed to adapt to many habitats, rendering several herbicides ineffective. If an early detection and eradication fails, multiple management strategies should be adopted to mitigate a further dispersal. Herbicides should be applied before or during flowering to prevent the formation of berries and the production of seeds. Precision agriculture tools, such as decision support systems, can be exploited to reduce the herbicide input. Soil tillage should be avoided to prevent clonal reproduction. Mowing is an effective tool to prevent the setting of seeds. Biological agents should be carefully released as a part of an agroecological weed management framework. Future research should focus on the development of cross-boundary protocols and actions to monitor the introduction pathways for the early detection and agroecological management of S. elaeagnifolium.

Cinmethylin, a pre-emergent applied active ingredient, inhibits the fatty acid thioesterase and offers a new option in the chemical control of Alopecurus myosuroides, one of the most problematic weeds in arable farming in Europe. It was assumed that with the delayed sowing of winter wheat and winter barley due to more humid and cooler conditions, the efficacy of cinmethylin against A. myosuroides increases. Four field trials were conducted in Southwestern Germany from 2019 to 2022. From mid-September until early November, winter wheat and winter barley were sown in at four dates each year, with intervals of fourteen days. After each sowing, 500 and 250 g cinmethylin ha−1 were applied subsequently to winter wheat and winter barley, respectively. Flufenacet (240 g ha−1) served as a comparison in both crops. A herbicide efficacy of over 90% was achieved for winter wheat sown in mid-October, while it was only 70% for winter wheat sown in mid-September. Similar results were observed for winter barley. On average, cinmethylin achieved a significantly higher efficacy in winter wheat than flufenacet. The presented approach with cinmethylin and delayed sowing date provides a basis for the comprehensive control of A. myosuroides. However, further measures of integrated weed management (crop rotation, situational ploughing, and stale seedbed) need to be applied for 100% control.

Wild oat is a nuisance monocot weed mainly in cereal canopies. The increasing problem of herbicide resistance and the implementation of integrated pest management includes the use of seed meals from species with allelopathic potential. This study aimed to assess the efficacy of seed meals as an environmentally friendly alternative for the control of herbicide-susceptible (S) and -resistant (R) wild oat biotypes. A pot experiment was carried out under greenhouse conditions at the Swojczyce Research and Training Station in Wrocław (Poland) to determine the impact of seed meals from Fagopyrum esculentum, Lupinus luteus, Ornithopus sativus, Phacelia tanacetifolia, Raphanus sativus var. oleiformis and Sinapis alba at two concentrations—1 and 3%. The lowest percentage of seedling emergence was recorded after the application of S. alba seed meal. Seed meals from S. alba reduced the emergence of both S and R biotypes by approximately 82 and 61 percentage points, respectively, and limited the initial growth of both biotypes. F. esculentum, O. sativus and R. sativus seed meals generally did not decrease the number of seedlings. Almost all the seed meals inhibited the growth of the aboveground parts of the susceptible biotype of wild oat to a greater extent than the herbicide treatment.

Pelargonic acid is a non-selective post-emergence contact bio-herbicide which is registered both for cropping and non-cropping uses in several countries. Dose–response curves on the efficacy of pelargonic acid against common weeds in Mediterranean areas are not available. Dose–response curves of pelargonic acid efficacy against summer and winter annual weeds were evaluated in two field experiments (winter exp. in 2019 and summer exp. in 2020) in central Italy. Pelargonic acid was applied at five doses (1.4, 2.7, 5.4, 10.9 and 21.8 kg a.i. ha−1). Data on weed density, weed dry weight, and weed ground cover were used to calculate the efficacy of pelargonic acid against winter and summer weeds. Data were subjected to a non-linear regression analysis using the logistic dose–response model. Dose of pelargonic acid required to obtain 50%, 70%, 90% and 95% weed control against each weed species (ED50, ED70, ED90 and ED95) were estimated. ED values allowed us to classify winter and summer weeds with respect to their susceptibility to pelargonic acid (ED50 values in kg ha−1 are reported in parenthesis): Kickxia spuria (2.6) (more susceptible) > Heliotropium europaeum (3.0) > Echinochloa crus-galli (3.4) > Solanum nigrum (3.6) > Stachys annua (5.3) > Papaver rhoeas (6.5) > Veronica hederifolia (10.3) > Amaranthus retroflexus (11.4) > Matricaria chamomilla (11.6) > Portulaca oleracea (18.7) > Lolium multiflorum (>21.8) (less susceptible). These findings will allow for the optimization of weed control by pelargonic acid and its use in weed management strategies, both in organic and sustainable cropping systems, under different environmental conditions.

Cyperus aromaticus (Navua sedge) is a problematic perennial weed in pastures and crops including sugarcane, banana, rice, and fruits and vegetables in tropical climates. It reproduces both via rhizomes and seeds. As a regenerative and storage organ, these rhizomes play an important part in the invasion, establishment, and persistence of this weed. To eliminate their regenerative ability, it is important to understand the regrowth potential with respect to rhizome fragment size and burial depth. This study evaluated the emergence of C. aromaticus from rhizomes in a controlled condition. Three different sizes of rhizome fragments were buried at seven depths of up to 20 cm in two soil types. The experimental measurements included (i) the time for tillers to emerge, (ii) the cumulative emergence of tillers, recorded weekly, and (iii) the number of underground emerging tillers. The cumulative shoot emergence and the number of underground tillers produced were found to be positively correlated with the initial length of the rhizome fragments and negatively correlated with the burial depth. The time for the emergence of the tillers was negatively correlated with the burial depth, and soil type had no significant effect on any of the parameters recorded. There was no emergence recorded from rhizomes buried at 15 cm depth and deeper, irrespective of their size. Our results indicate that the combination of the fragmentation of rhizomes into small pieces and a deep burial, below 15 cm, is an important aspect to control the regeneration of C. aromaticus from rhizomes, if tillage is carried out, and can therefore form a part of an integrated weed management strategy for this troublesome weed.

Infestations by the parasitic weed genus Striga result in significant losses to cereal crop yields across sub‐Saharan Africa. The problem disproportionately affects subsistence farmers who frequently lack access to novel technologies. Effective Striga management therefore requires the development of strategies utilizing existing cultural management practices. We report a multiyear, landscape‐scale monitoring project for Striga asiatica in the mid‐west of Madagascar, undertaken over 2019–2020 with the aims of examining cultural, climatic, and edaphic factors currently driving abundance and distribution. Long‐distance transects were established across the middle‐west region of Madagascar, over which S. asiatica abundance in fields was estimated. Analysis of the data highlights the importance of crop variety and legumes in driving Striga density. Moreover, the dataset revealed significant effect of precipitation seasonality, mean temperature, and altitude in determining abundance. A composite management index indicated the effect of a range of cultural practices on changes in Striga abundance. The findings support the assertion that single measures are not sufficient for the effective, long‐term management of Striga. Furthermore, the composite score has potential as a significant guide of integrated Striga management beyond the geographic range of this study. [ABSTRACT FROM AUTHOR]

The targeted treatment of weeds is an expanding part of precision farming in many countries. Targeted weed treatments, using precision spray maps, reduce herbicide consumption, whilst still maintaining long term weed control. Assembling accurate spray maps is a vital part of this process. However, acceptable accuracy in spray maps is difficult to quantify, due in part to rapid technological advances in cameras, weed recognition software, and herbicide decision support systems (DSS). This research applied a DSS to repeated samples from field gathered weed data. Variability in the herbicide recommendations when different numbers of images were used for the same areas (polygons) within a field were examined. Type 2 errors (not recommending herbicide where it was needed), were analysed separately to type 1 errors (recommending herbicide where it was not needed). Type 2 errors were more common than type 1 errors in diagnosing herbicides to control Viola arvensis in Field 1, and Poaceae species in Field 2, and were also more common with systematically dispersed images compared to randomly dispersed images. In contrast, type 2 errors were less common than type 1 errors for Poaceae species in Field 1. Variability in herbicide recommendations differed for herbicides but was generally reduced (1) with greater numbers of images per polygon; (2) by using regularly arranged images; and (3) for datasets with greater ratios of 'empty' (not needing spray) polygons. Targeted treatments reduced herbicide use to 3–11% of the rate recommended for blanket spraying of the same weeds. High numbers of 'empty' polygons gave better results with lower relative percentages of type 1 errors. These results highlight the need to focus on reducing type 2 errors in spatial herbicide recommendations. [ABSTRACT FROM AUTHOR]