Abstract: Allelopathy is a form of amensalism, an association between organisms in which one is inhibited or destroyed and the other is unaffected through the release into the environment of secondary metabolites called allelochemicals. Allelopathic plant interactions has been known since the 4th century before Christ (BC), but only in recent years they have received an appropriated attention from international scientific community and farmers. Nowadays, in modern agriculture, allelopathy play a key role in maintenance the sustainability of agroecosystems through the adoption of environmentally-friendly strategies such as crop rotation, cover or smother crops, intercropping, crop residue incorporation, mulching and bioherbicides. Crops showing allelopathic properties are numerous: they include arboreal and herbaceous species as well as many weeds. Here we review the general principles and the basic aspects in the field of allelopathy and why they are important in developing innovative sustainable agricultural techniques in agroecosystems for weed control, crop protection, and crop re-establishment with respect of environmental, human and animal health. Particularly, we describe the guidelines for distinguishing allelopathy from competition in field conditions, as well as the chemical nature of allelochemicals. Secondly, we review the volatilization from living parts of the plant, the leaching from aboveground parts of the plant, the decomposition of plant material and the root exudation, which are the major pathways for the release of allelochemicals. Third, we review the influence of abiotic and biotic stress factors on the quantity of allelochemicals released by the donor plant and the effects of allelochemicals on the target plant. Light, temperature, water deficiency, minerals availability, soil characteristics and many biotic factors modify the production of allelochemicals and the sensitivity of target plants. Finally, the interference of alleochemicals with plant physiological processes was also reviewed. Allelopathic compounds rarely act alone, but generally generate “multiple cascating effects”. Allelopathic mechanisms influence plant successions, invasion, spatial vegetation patterns, mutualistic associations, soil nitrogen cycle, crop productivity and crop protection.

Abstract: The current study aimed to evaluate the negative allelopathic effect of Eucalyptus citriodora essential oil on some of the most noxious weeds in Algeria (Sinapis arvensis, Sonchus oleraceus, Xanthium strumarium and Avena fatua). Gas chromatography-flame ionization detector (GC-FID) and GC/mass spectrometry (MS) were used to define the chemical composition of the oil. Citronellal (64.7%) and citronellol (10.9%) were the major essential oil compounds. Three concentrations of the oil were used for laboratory (0.01, 0.02 and 0.03%) and greenhouse (1, 2 and 3%) experiments. Seed germination and seedling's growth were drastically reduced in response to the oil concentrations where at 0.01 and 0.02% the oil drastically affects the seed germination of the tested weeds and at 0.03% the oil suppresses completely the germination of S. arvensis. The oil also exhibited strong allelopathic effect on the 3 - 4 leaf-stage plants 1 and 6 days after treatment. A completely death of S. arvensis, S. oleraceus and A. fatua and severe injuries on X. strumarium appeared at 3% of the oil. Chlorophyll content and membrane integrity were significantly affected after treatment of the plant weeds representing a severe reduction in total chlorophyll and cell membrane disruption. The study concludes that E. citriodora essential oil might has the potential use as bioherbicide and can constitute an alternative process of weed control.

Abstract: Biostimulants are the next-generation choice for sustainable agricultural production and are gradually becoming an alternative to synthetic chemicals Various botanicals are proposed to exert stimulatory effects, and garlic allelochemicals are among such botanicals; however, a peer-reviewed scientific evaluation is required to understand garlic-derived substances such as biostimulants Current studies were therefore performed to identify the bioactivity of garlic extract as a biostimulant to improve crop quality, alter its physiological potential, and prime its defense responses against pathogenic fungal infections 100 µg mL−1 aqueous garlic extracts (AGE) in consort with 1 mM of acetyl salicylic acid (ASA) and distilled water as a control treatment were applied to eggplant and pepper seedlings as foliar application and fertigation methods The results revealed stimulatory responses in the growth of the vegetables with improved plant height, number of leaves, root growth, fresh and dry weight, etc, due to AGE and ASA applications Moreover, significant alterations were indicated in plant metabolites such as chlorophyll, carotenoids, and soluble sugars Additionally, stimulation of the antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD), as well as the root activity of these plants, was observed after treatment Application of AGE and ASA also exerted priming effects on pepper plants, inducing defense responses prior to Phytopthora capsici inoculation, and the treated plants therefore successfully resisted infection through activated antioxidant systems, and probably carotenoid and other protectory metabolites Stress-induced H2O2 content was extremely low in the treated plants, indicating successful resistance against pathogenic infection

Abstract: At the global level, the invasion of alien organisms is considered the second largest threat to biodiversity. The assumption is that the high allelopathic potential is one of the features that helps invasive plant species to spread to new areas. In the study was determined allelopathic potential of eight invasive plant species (donor species) and their impact on test-species. Donor species were Abutilon theophrasti Med. - velvetleaf (Malvaceae), Ambrosia artemisiifolia L. - ragweed (Asteraceae), Datura stramonium L. - white jimsonweed (Solanaceae), Xanthium strumarium L. - cocklebur (Asteraceae), Ailanthus altissima (Mill.) Swingle - tree of heaven (Simaroubaceae), Amorpha fruticosa L. - indigo bush (Fabaceae), Reynoutria japonica Houtte. - Japanese knotweed (Polygonaceae), Solidago gigantea Aiton - giant goldenrod (Asteraceae). Three cultivated plant species from three different plant families were used as test-species: Avena sativa L. - oats (Poaceae), Brassica napus L. - oilseed rape (Brassicaceae) and Helianthus annuus L. - sunflower (Asteraceae). Water extracts made of whole plants of donor species were applied to the seeds of the test-species. High allelopathic potential was proven for all species included in experiment. Allelopathic effects were exclusively negative. Impact on the germination for all species is much smaller in relation to the impact on the radicle and shoot length of the test-species. Perennial species had a stronger allelopathic potential than annual species. Tree of heaven is species with the strongest allelopathic potential. Its extracts inhibited germination, radicle and shoot length of oilseed rape 19%, 94.88% and 98.91% respectively. Applying allelopathy in agriculture can reduce the use of synthetic pesticides.

Abstract: The formation, propagation, and maintenance of harmful algal blooms are of interest due to their negative effects on marine life and human health. Some bloom-forming algae utilize allelopathy, the release of compounds that inhibit competitors, to exclude other species dependent on a common pool of limiting resources. Allelopathy is hypothesized to affect bloom dynamics and is well established in the red tide dinoflagellate Karenia brevis. K. brevis typically suppresses competitor growth rather than being acutely toxic to other algae. When we investigated the effects of allelopathy on two competitors, Asterionellopsis glacialis and Thalassiosira pseudonana, using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS)-based metabolomics, we found that the lipidomes of both species were significantly altered. However, A. glacialis maintained a more robust metabolism in response to K. brevis allelopathy whereas T. pseudonana exhibited significant alterations in lipid synthesis, cell membrane integrity, and photosynthesis. Membrane-associated lipids were significantly suppressed for T. pseudonana exposed to allelopathy such that membranes of living cells became permeable. K. brevis allelopathy appears to target lipid biosynthesis affecting multiple physiological pathways suggesting that exuded compounds have the ability to significantly alter competitor physiology, giving K. brevis an edge over sensitive species.

Abstract: In the worldwide search for new strategies in sustainable weed management, the use of allelopathic plants incorporated into the soil as green manure can help control weeds by releasing allelochemicals into the environment. In previous experiments, Eucalyptus globulus leaves incorporated into the soil as green manure were shown to have a notable potential for weed control. But, ‘what was exactly happening at chemical level?’ and ‘which were the compounds potentially responsible for the phytotoxic effects observed during those greenhouse assays?’ In the present study, in-vitro phytotoxicity bioassays and chemical analysis of eucalyptus leaves were carried out in order to explore the relationship between the temporal phytotoxic effects and the dynamics of chemical composition. For that, eucalyptus leaves were removed from soil at different sampling times during 30 days and analyzed for phenolic and volatile organic compounds (VOCs) by HPLC and HS-SPME/GC-MS, respectively. The phytotoxic potential of the aqueous extract and the volatile fraction was tested on the germination and early growth of Lactuca sativa. Eucalyptus leaves incorporated into the soil as green manure showed a continuous release of different phenolic and volatile compounds during a 30-day period of decomposition. Both fractions had phytotoxic effects during the time assayed; however, the target process of phytotoxicity was different: phenolic compounds being the factor causing germination inhibition and VOCs responsible for growth reduction. The dynamics of release of this cocktail of allelochemicals into the soil environment may be the responsible for the phytotoxicity observed in our previous works.

Abstract: Members of Brassicaceae have been frequently cited as allelopathic crop. The toxic effect of Brassica spp. may be caused by hydrolysis products of glucosinolates that occur in substantial amounts in the vegetative parts of Brassica spp. This study investigated the allelopathic potential of Brassica napus, B. rapa and B. juncea on the sunflower seed germination and seedling growth. Aqueous extracts of three species from two stages (full flowering and straw) of sampling were separately made with 0 (distilled water), 10, 20, 30 and 40% concentrations. This experiment was conducted in 2 × 3 × 5 factorial arrangement based on completely randomized design with five replications. There was a highly significant difference among different concentrations of extracts and also between two stages of extrac tion. All aqueous extracts significantly affected sunflower germination, germination rate, seedling root and hypo cotyl length, fresh and dry matter weight when compared with distilled water control. The greatest concentration showed a stronger inhibitory effect. Root length was more sensitive to extracts than hypocotyl length.

Abstract: Allelopathy is an important ecological mechanism in natural and managed ecosystems. Its study is critical to understand natural plant behaviors, to isolate allelochemicals with herbicide potential, and to use the allelopathic genes in transgenic studies. Poaceae is an ecologically dominant plant family and it is economically important worldwide because its chemical diversity represents an important source to discover new molecules. From this viewpoint, Brazil is an interesting place to study, encompassing 197 genera of the Poaceae family, many of them being dominant in various biomes and some being native to Brazil. Here, we review the literature describing allelopathic activities involving grasses of the Poaceae family. We evaluate the experimental conditions used in these studies, we identify the allelochemicals involved, and, finally, we assess the applicability of allelopathy. Our main findings are (1) among the 47 Brazilian species studied for their allelopathic effects, only Bothriochloa barbinodis, Bothriochloa laguroides, Paspalum notatum, and Paspalum urvillei are native to Brazil; (2) 51% of the reviewed studies prepared extracts from the leaves and used lettuce as the target plant; and (3) 64% of the papers identified allelochemicals, of which 67% were phenolic acids. This first bibliographical survey on allelopathy in Poaceae species present in Brazil shows that less than 3% of the Brazilian species have been studied, suggesting it is an incipient research subject. Since this plant family is a valuable source of unknown natural products, refining such studies should contribute to a better understanding of the ecosystem relationships. Identification and isolation of grass allelochemicals should promote environmentally safer compounds with bioherbicide properties, in sustainable agriculture.

Abstract: Introduction Weeds are an important factor in determining production in the agricultural sector. Currently, weeds have been managed by employing synthetic weedicides chemicals. These chemicals have a negative impact on the environment through accumulation in soil and water, in addition to their effect on biological diversity. Material and methods A study was undertaken to evaluate the activity of the aqueous extract of leaves from; Nerium (Nerium oleander L), olives (Olea europaea L) and castor (Ricinus communis L) on the control of Cyperus rotundus L. The study comprised of two components: three plant species, and the uses of three planta extracts concentration (5%, 7.5% and 10%) and their impact on germination and inhibition of seedling growth. Results The results from using Nerium extract in comparison with Tibenuron and the two other plants extracts gave 90% inhibition at concentrations of 5% and 10%, while the concentration of 2.5% gave the lowest inhibition rates for germination of all plant extracts under study. The second experiment carried out using 10% concentration of the Nerium extract gave complete inhibition (100%), compared with the same concentrations of other plants extract and weedicides. Conclusions The current study indicates the possibility of using natural products of plant origin as alternatives to chemical herbicides as one of the means of biological control to reducing environment pollution.

Abstract: Utilization of Salvinia molesta, an aquatic weed which is notorious for its allelopathy and invasiveness, has been explored by its vermicomposting. Fourier transform infrared spectroscopy (FT-IR) and plant bioassay tests were conducted to analyze the composition and fertilizer value of S .molesta vermicompost. Germination and seedling growth tests were performed in soil supplemented with vermicompost at levels ranging from 0.75 to 40% by weight of the soil on three common food plants, ladies finger (Abelmoschus esculentus), cucumber (Cucumis sativus), and green gram (Vigna radiata). The influence of S. molesta's vermicompost on some of the physicochemical and biological attributes of the soil was also studied. FT-IR analysis revealed that S. molesta loses its allelopathy, as the chemical compounds that are responsible for it are largely destroyed, in the course of its vermicomposting. There is also an indication that a portion of lignin content of S. molesta is degraded. Vermicompost enhanced the germination success and promoted the morphological growth and biochemical content of the plant species studied. It also bestowed plant friendly physicochemical and biological attributes to the soil. The findings raise the prospect that billions of tons of S. molesta biomass-which not only goes to waste at present but is also a cause of serious harm to the environment-may become utilizable in organic agriculture.

Abstract: Weed control by crops through growth suppressive root exudates is a promising alternative to herbicides. Buckwheat (Fagopyrum esculentum) is known for its weed suppression and redroot pigweed (Amaranthus retroflexus) control is probably partly due to allelopathic root exudates. This work studies whether other weeds are also suppressed by buckwheat and if the presence of weeds is necessary to induce growth repression. Buckwheat and different weeds were co-cultivated in soil, separating roots by a mesh allowing to study effects due to diffusion. Buckwheat suppressed growth of pigweed, goosefoot and barnyard grass by 53, 42, and 77% respectively without physical root interactions, probably through allelopathic compounds. Root exudates were obtained from sand cultures of buckwheat (BK), pigweed (P), and a buckwheat/pigweed mixed culture (BK-P). BK-P root exudates inhibited pigweed root growth by 49%. Characterization of root exudates by UHPLC-HRMS and principal component analysis revealed that BK and BK-P had a different metabolic profile suggesting that buckwheat changes its root exudation in the presence of pigweed indicating heterospecific recognition. Among the 15 different markers, which were more abundant in BK-P, tryptophan was identified and four others were tentatively identified. Our findings might contribute to the selection of crops with weed suppressive effects.

Abstract: We have tested the effect of water, methanol and dichloromethane extracts from the leaves of several species of Impatiens (I. noli-tangere, I. parviflora , I. glandulifera) on germination of seeds Leucosinapis alba and Brassica napus. All of the tested extracts had inhibitory effects to seeds of all studied plants (except the dichloromethane extracts). The highest activity revealed methanol extract and extract from I. glandulifera.

Abstract: Our objective was to determine which rhizome extract from Japanese knotweed, Giant knotweed or Bohemian knotweed has the most significant inhibition effect on the germinated seeds. The seeds of white mustard were incubated with the extracts for two days under laboratory conditions. We monitored differences in number of germinated seeds, length of radicles, hypocotyls and root/shoot ratio between the control and experimental seeds. Inhibitory effect of extracts from dried knotweed rhizomes was confirmed, but without differences among tested plants. A higher allelopathic effect was revealed in the case of extract from aboveground parts.

Abstract: People rely on the synthetic chemical pesticides in most of the agricultural practices, which have a serious problem on human health and ecosystem. Essential oil (EO), derived from wild plants, offers a new opportunity to explore eco-friendly green biocides. This study aimed to characterize the chemical constituents of EO from Egyptian ecospecies of Cleome droserifolia (Forssk.) Delile and evaluate its antioxidant and allelopathic potential. The EO was extracted from aerial parts by hydrodistillation and analyzed by GC/MS. To assess the allelopathic potential, EO concentrations from 50 to 200 μL L-1 were tested on Trifolium repens and three weeds. Antioxidant activity was determined using DPPH. Hydrodistillation yielded 0.64 % of dark yellow oil, which comprises 35 compounds, in which sesquiterpene was a major class and represented by 61.97 % of the total essential oil. Moreover, the dominant sesquiterpenes are cis-nerolidol, α-cadinol, δ-cadinene, and γ-muurolene. The speed of germination index, shoot and root length of clover and weeds were reduced in a concentration-dependent manner. The IC50 values of C. droserifolia EO on germination of T. repens, Cuscuta trifolii, Melilotus indicus, and Chenopodium murale were 181.6, 183.5, 159.0, and 157.5 μL L-1 , respectively. From the obtained data, we concluded that C. droserifolia EO could provide a hope to produce environment-friendly bioherbicide as well as a natural resource of antioxidants.

Abstract: Allelopathic effects on the seed germination and seedling development of co-occurring native plant species (natives hereafter) are regarded as an important driver facilitating invasion of many invasive plant species (invaders hereafter). The release of silver nanoparticles (AgNPs) into the environment may affect the allelopathic effects of the invaders on the seed germination and seedling development of natives. This study aims to assess the allelopathic effects (using leaf extracts) of Canada goldenrod (Solidago canadensis L.) on the seed germination and seedling development of native lettuce (Lactuca sativa L.) treated with AgNPs with different particle sizes. Canada goldenrod leaf extracts with high concentration exhibit stronger allelopathic effects on the seedling height and root length of lettuce than those treated with low concentration. AgNPs of all particle sizes significantly decreased seed germination and seedling development indices of lettuce. AgNPs with larger particle sizes exerted stronger toxicity on leaf length and width of lettuce than those with smaller particle sizes. Thus, nanoparticles with larger particle sizes might mediate the production of increased sizes of cell wall pore size and large absorption of such substances by plant roots can be harmful. AgNPs significantly enhanced the allelopathic effects of Canada goldenrod on the seed germination and seedling development of lettuce. Small particle size AgNPs may play a more essential role in the enhanced allelopathic effects of low concentrations of Canada goldenrod leaf extracts; however, large particle size AgNPs may play a more important role in the enhanced allelopathic effects of high concentrations of Canada goldenrod leaf extracts.

Abstract: Aromatic plants attract the attention of many researchers worldwide due to their worthy applications in agriculture, human prosperity, and the environment. Essential oil (EO) could be exploited as effective alternatives to synthetic compounds as it has several biological activities including allelopathy. The EO from the aerial parts of Rhynchosia minima was extracted by hydro-distillation and investigated by gas chromatography/mass spectrometry (GC-MS). Different concentrations (50, 100, 150 and 200 μL L−1) of the EO were prepared for investigation of their allelopathic potential on two weeds; Dactyloctenium aegyptium and Rumex dentatus. Twenty-eight compounds, mainly sesquiterpenes (69.13%) were determined. The major compounds are α-eudesmol, 2-allyl-5-t-butylhydroquinone, caryophyllene oxide, trans-caryophyllene, and .tau.-cadinol. The VOCs from the R. minima showed a significant inhibition of D. aegyptium and R. dentatus germination, while the seedling growth was stimulated. Therefore, it is not recommended to treat these noxious weeds with the EO of R. minima before the germination. In contrast, the apparent stimulatory effect on the seedling growth offers further studies to use the EO of R. minima to enhance the fitness of different economic crops. However, characterization of green bio-herbicides such as EO (allelochemicals) from wild plants raises a new opportunity for the incorporation of new technology of bio-control against the noxious weeds. This article is protected by copyright. All rights reserved.

Abstract: Invasive plant species such as Ludwigia hexapetala might have a competitive advantage if they produce allelopathically active compounds against primary producers. Both phytoplankton and plant community structure may be affected due to different, species-specific sensitivity to allelochemicals. Moreover, such allelopathic interactions could vary over the year depending on (i) the plant's phenological stage and (ii) the abilities of the native macrophytes to suppress—or the non-native macrophytes to stimulate—the non-native macrophyte population. We tested the allelopathic effects of aqueous leaf extracts of L. hexapetala on the photosynthetic activity of three target phytoplankton strains (Scenedesmus communis, a toxic Microcystis aeruginosa strain and a non-toxic Microcystis aeruginosa strain) over three seasons of development (spring, summer and autumn). We also tested seasonal allelopathic effects of aqueous leaf extracts of both L. hexapetala (i.e. the non-native invasive species) and the native Mentha aquatica on L. hexapetala seed germination. Finally, we identified three main secondary compounds present in the aqueous leaf extracts of L. hexapetala and we tested each individual compound on the phytoplankton's photosynthetic activity and on L. hexapetala seed germination. We observed marked seasonal and species-specific patterns of L. hexapetala allelopathy on phytoplankton. The photosynthetic activities of S. communis and the toxic M. aeruginosa strain were stimulated by L. hexapetala aqueous leaf extracts in autumn and spring, respectively, whereas the non-toxic M. aeruginosa strain was strongly inhibited in these two seasons. In summer, photosynthesis of all phytoplankton strains was inhibited. The germination rate of L. hexapetala seeds was stimulated by both L. hexapetala and M. aquatica aqueous leaf extracts, especially in summer, concomitant with the strong negative effects observed on the three phytoplankton strains. Three flavonoid glycosides (myricitrin, prunin and quercitrin) were identified as the main secondary compounds present in the L. hexapetala aqueous leaf extracts. The photosynthetic activity of S. communis was slightly stimulated by the three compounds. The photosynthetic activity of the toxic M. aeruginosa strain was stimulated by myricitrin and quercitrin, whereas that of the non-toxic M. aeruginosa strain was inhibited by prunin. Finally, the germination rate and the germination velocity of L. hexapetala seeds were stimulated by myricitrin and prunin. These findings suggest that L. hexapetala could favour the photosynthetic activity of toxic cyanobacteria in spring and reduce their photosynthetic activity in summer, potentially leading to drastic changes in the phytoplankton communities and therewith ecological functioning of invaded ponds. Moreover, the stimulation of its seed germination could give a strong competitive advantage to L. hexapetala, thus promoting its invasiveness. © 2018 John Wiley and Sons Ltd

Abstract: Eichhornia crassipes is an invasive, floating macrophyte and may have biocontrol functions on harmful cyanobacteria blooms. Eichhornia produces N-phenyl-2-naphthylamine (PNA), a compound which can inhibit algae. However, the impact of PNA on allelopathic effects of the cyanobacterium Microcystis aeruginosa on other phytoplankton species is not clear. In this study, we tested whether PNA can influence the allelopathic effect of M. aeruginosa on the green alga Scenedesmus quadricauda. S. quadricauda was more sensitive to PNA than M. aeruginosa, with 72 h-EC50 values of 0.42 and 3.66 mg L−1, respectively. In addition, PNA significantly enhanced allelopathy by M. aeruginosa on S. quadricauda. Consequently, PNA had a greater impact on the green algae when Microcystis was present. In complex ecosystems with multiple species that release allelopathic substances, unintended interspecific interactions may occur, where allelopathy plays an important role under artificial or even natural contexts. It is hard to predict the competition outcomes among allelopathic organisms in these complex ecosystems, therefore a precautionary approach is required for biological control of algae.

Abstract: Allelochemicals are the media of allelopathy and form the chemical bases of plant-environment interactions. To determine true allelochemicals and their autotoxic effects, seven compounds were isolated and identified from in-situ sampled rhizosphere soil of cultivated Saussurea lappa. Of these; costunolide (2), dehydrocostus lactone (3) and scopoletin (4) showed significant inhibition on seedling growth in a concentration-dependent manner. Detection and observation demonstrated that the antioxidase system was found to be affected by these chemicals, resulting in the accumulation of ROS and membrane damage. To investigate their release ways, the compounds were traced back and volumes quantified in rhizosphere soil and plant tissues. This work made clear the chemical bases and their physiological effects on the plants. These chemicals were found to be the secondary metabolites of the plants and included in the rhizosphere soil. The findings identified a potential pathway of plant-plant interactions, which provided theoretical basis to overcoming replanting problems. This research was also useful for exploring ecological effects of allelochemicals in green agriculture.

Abstract: Soil microbial communities are crucial to the functioning of agricultural systems but little information is available on the effects of allelochemicals on soil microorganisms in vivo. Cucumber seed...

Abstract: Allelopathy is a biological process in which plants synthesize allelochemicals that affect the physiological properties, development and survival of other plants. Experiments were conducted to inve...

Abstract: Allelopathy could be explored as a sustainable strategy in the management of weeds amidst the growing concern of herbicide-resistant/tolerant weeds. However, many articles and research do not provide proof of the practical applications of allelopathy in weed anagement. For the sustainable utilization of allelopathy in the management of weeds, the allelopathic activities of many plants were evaluated by various specific bioassays and field experiments. In conclusion, two leguminous plants, hairy vetch (Vicia villosa) and velvet bean (Mucuna pruriens) were the most promising allelopathic ground cover plants. L-DOPA, an unusual amino acid from velvet bean and cyanamide from hairy vetch were identified as allelochemicals that played important roles in the reported weed suppression by these species. Direct application of these plants to farmlands showed that these plants could suppress weed without using herbicides and also act as nitrogen fertilizer. By utilizing these plants, sustainable agriculture without or with minimal artificial herbicides might be possible in rice, vegetable, and fruit productions.

Abstract: Use of synthetic herbicides to control weeds poses serious threats to sustainable agricultural production around the globe. The phytotoxic effect of different plant water extracts (i.e., sorghum, sunflower and mulberry) against weeds has been previously studied; however, their combined effects at different rates are yet to be explored. In this study, mixtures of allelopathic water extracts of sorghum + sunflower and sorghum + sunflower + mulberry were sprayed each at 12, 15, 18 and 21 L ha-1 at 40 and 55 days after sowing in wheat to control wild oats (Avena fatua), little seed canary grass (Phalaris minor), lamb’s quarters (Chenopodium album) and swine cress (Coronopus didymus). A synthetic herbicide Affinity 50 WP (Carfentrazone-ethyl 0.75% + Isoproturon 50% applied at 1000 g a.i., ha-1) and a weedy check were kept as a control treatment. The increasing order of water extract dose 12-21 L ha-1 showed substantial reduction in total weed density and their dry biomass production of both narrow and broad-leaved weeds in all the treatment combinations. Mixture of sorghum + sunflower + mulberry water extracts each at 18 L ha-1 applied at 40+55 DAS resulted in an 87.14% decrease in total weed dry matter with a 19.5% increase in grain yield of wheat and higher net benefits of Rs. 100525 with 777.5% marginal rate of return. Nonetheless, application of sorghum + sunflower water extracts each at 12 L ha-1 at 40+55 DAS was more economical than the other treatments in terms of higher marginal rate of return of 799.82%. Based on this study, it can be suggested that the use of allelopathic plant water extracts in a mixture may act as a potential weed control strategy in wheat.