Alternative Weed Control Methods Research Articles

Soil Actinomycetes as Promising Alternative to Synthetic Herbicides


 Weed management is a key agronomic practice in agriculture. Since decades, synthetic herbicides played an indispensable role in weed control due to high effectiveness. However, recently there has been growing interest on exploring alternative weed control methods due to negative impacts of synthetic herbicides on the environment. Besides, there is an increasing demand for organic farm products. Actinomycetes, a group of filamentous, Gram-positive bacteria known for their bioactive secondary metabolites, have emerged as potential candidates for bioherbicides. In this study, we investigated herbicidal potential of twenty-three morphologically distinct actinomycetes strains isolated from soil using lettuce (Lactuca sativa) as a model plant. Eight weeks-old cell-free culture fermentation broth of actinomycetes strains were used for screening the effect on seed germination and seedling growth. Lettuce seeds were exposed to fermentation broth for two weeks while for control, sterilized distilled water was used. Ten seeds per treatment in three replicates were used. The results showed that sixteen actinomycetes strains, ACM25, 26, 29, 33, 34, 35, 36, 38, 41, 42, 43, 47, 48, 49.1 and 49.2 and ACM50 were able to completely inhibit seed germination while seeds treated with ACM32 did not produce roots although seed germination had initiated. It appears that these seventeen strains would be effective at pre-emergence weed control. Seeds that treated with the rest of the six strains had no effect on the seed germination. However, seedlings of ACM24, 45 and ACM46-treated seeds showed deaths by two weeks. Their gradual death started with discoloration of leaves followed by watery rotting of the entire plant. Seedlings of ACM30, 31, 37- treated seeds survived, and their growth performance were observed for two weeks compared to the control. Seedlings were dwarf and exhibited growth deformations such as reduced leaf size, chlorosis, leaf curling and stunted roots. Further, number of leaves, shoot length and root length were significantly different (p<0.05) from that of the control. These observations suggest that the effect of ACM24, 30, 31, 37, 45 and ACM46 would be systemic. In conclusion, our results clearly showed strong herbicidal effects of all tested twenty-three strains of actinomycetes at pre- and post- emergence stages of seed germination. Thus, they can be promising candidates for bioherbicide formulations.
 
 Keywords: Actinomycetes, Bioherbicides, Weed management, Sustainable agriculture

Weed Management in Ajwain (Trachyspermum ammi L.) at Farmer’s Fields in South East Rajasthan

The field experiments were conducted during kharif (July–October) seasons of 2014–15 and 2015–16 at KVK, Rajsamand, Rajasthan and farmers’ field with objective to explore and test other alternative and economical methods of weed control. On-farm Trial, technology option Oxadiargyl applied 50 g a.i. ha-1 applied as early post emergence at 20 DAS proved the best over farmers’ practice as well over recommended practice of 1.0 kg a.i. ha-1 pendimethalin pre-emergence in terms of growth and yield attributing characters viz., plant height, primary and secondary branches, number of umbels, number of umbellets umbel-1, number of seeds umbel-1 and remained statistically at par with weed free treatment. Weed indices namely weed count, weed dry weight, weed index and weed control efficiency were statistically significant by oxadiargyl applied 50 g a.i. ha-1 as early post emergence at 20 DAS and pre-emergence application of pendimethalin 1.00 kg a.i. ha-1 pendimethalin over farmer’s practice. Lower WI and higher WCE was observed by oxadiargyl applied 50 g a.i. ha-1 followed by pendimethalin 1.00 kg a.i ha-1. Grain and starw yield recorded in weed free plot was statistically at par with yield obtained by application of oxadiargyl 50 g a.i. ha-1. Net returns and B:C were also high in refined technology option i.e. of 50 g a.i. ha-1 oxazdiargyl (` 127570 ha-1 and 4.77) over recommended practice of 1.0 kg a.i ha-1 pendimethalin pre-emergence (` 107930 ha-1 and 4.19) and farmers’ practice (` 75930 ha-1 and 3.49).

Različite kontrole mehaničkog načina uništavanja korova u vinogradu zbog redukcije ekološkog otiska

The purpose of the study was to investigate the alternative methods of weed control in the vineyard under 'Sauvignon' vines to reduce ecological footprint in vineyard production. Weed control was performed at the experimental site with the mechanical weed control under vines with a grass cutter, a rotating star hoe (roll hoe) and a vine trunk cleaner, while at the same time additional mulching was carried out in the belts between the rows. The ecological footprint of each production operation was estimated by including environmental impacts related to fossil-C (kg CO2/hm2 ), air, water, soil, nonrenewable, renewable, and area resources. While carrying out the mechanical control, we analysed the weed coverage, grape yield and yield loss. Grape yield was highest for weedfree control plots, followed by plots where ploughshare was used. Yield loss was lowest when using ploughshare. In addition to the weed-free plot, weed coverage was lowest when glyphosate was used. The maximum amount of CO2 is released while using rotating star hoe. At the grass cutter and vine trunk cleaner less CO2 was released. The same is with global warming potential (GWP).

Substantiation of promising weed control methods in organic farming

Puprose. Determination of promising means of mechanization of weed control, which will allow growing tilled and vegetable crops in the organic farming system without the use of herbicides. Methods. Monographic, analytical, abstract-logical, structural modeling, design and manufacture of alternative technical means for the implementation of effective methods of weed control in the organic farming system. Results. Systematized and analyzed the main methods of weed control in the system of organic farming both in the world and in Ukraine. Alternative methods of weed control are: mechanical (mechanical removal, sprinkling), agrotechnical (mulching, crop rotation), biological, thermal (fire cultivation, hot water irrigation, steam treatment) and electrical (electric pulse, laser). In a separate group, it is necessary to single out precautionary measures that eliminate the possibility of introducing weed seeds to the fields from different sources. These include seed cleaning, proper manure storage, weed control outside the fields, compliance with quarantine measures, etc. Promising means of mechanization for weed control are cultivators with polyurethane finger-star-shaped working bodies for mechanical removal of weeds in the aisles and rows of crops and cultivators with installed equipment for fire cultivation. During fire cultivation, when the temperature of heating the soil does not exceed 70 °C, the proteins in the plant cells of weeds in the stages of “thread” and cotyledons are irreversibly damaged. In the phase of 4–6 leaves, at the same temperature, up to 90 % is destroyed, and in a later phase of development – up to 75 % of weeds. A study was made of the process of weed destruction by polyurethane finger-star-shaped working bodies, depending on the hardness and type of weeds on the experimental site (quinoa, amaranth, mouse), as a result of which from 80 % to 95 % are destroyed. Conclusions. The systematization and analysis of weed control methods in the system of organic farming was carried out, as a result of which the most promising means of mechanization and methods of weed control in vegetable and tilled crops were identified. It has been established that the integrated use of modernized elastic finger-star working bodies and fire cultivation for weed control in protective zones and rows of vegetable and tilled crops is effective. The design of a modern domestic row cultivator “FIGHTER” allows you to mount promising mechanical working bodies for weed control and equipment for fire cultivation. Keywords: weed control, organic farming, systematization of methods, mechanized vegetable cultivation, agrotechnical methods, creation of technical means, fire cultivation, rotary working bodies.

Načini suzbijanja korova u zasadu kruške

The weed control in the pear plantation is necessary to ensure a good yield and fruit quality. Herbicides present an effective method of weed control in the orchard. A modem approach to weed control implies a reduction in the use of Chemicals and the application of the alternative weed control methods, independently or combined. Classical mechanical methods (mowing, hoeing, manual removal, etc.) are the "traditional" methods for weed control. The more and more frequently applied non-chemical methods are the use of mulch, heat sources, water and the precise control (robots, drones, etc.). The main advantage of non-chemical methods is their environmental friendliness and sustainability.

The weevil, Hypolixus pica (F.) (Coleoptera: Curculionidae) as a potential biological control agent of Amaranthus species (Amaranthaceae) in Adana Province, Turkey

Amaranthus species (Family) are among the most important weeds in summer crops and orchards in Turkey. The detrimental effects of pesticides on the environment and human health and the development of high levels of resistance to several herbicide classes by Amaranthus species have generate interest in alternative weed control methods. Since the biological control of weeds has gained great prominence recently, this study was carried out to determine the potential biological control agents of Amaranthus spp. in Adana Province. Turkey. For this aim, ten randomly selected fields randomly were in three districts (Yüreğir-Ceyhan-İmamoğlu). In each field, ten Amaranthus plants were collected randomly and dissected, and the numbers of the weevils and theirdifferent stages were recorded. In this study, three Amaranthus species were identified and A. palmeri was the most common, followed by A. retroflexus and A. spinosus. Fifty-nine larvae, 26 pupae and 10 adults were collected from the Amaranthus plants. All adult individuals were identified as H. pica according to their genital organs. Our results show that H. pica could be considered to be a potential biological control agent of A. palmeri and A. retroflexus. More detailed studies are needed to determine its ecology and role as a biological control agent of the target weed species. In addition, it is crucial to develop mass rearing methods for potential beneficial insects such as H. pica.

Improving Pennsylvania Bittercress Weed Control Efficacy with Mulch and Herbicide in Containers

Pennsylvania bittercress (Cardamine pensylvanica) and other bittercress (Cardamine) species are among the most common and difficult-to-control weed species in container nurseries, and they have been vouched in most counties in Florida. Preemergence herbicides can provide control, but concerns over potential resistance development, environmental issues, and crop injury problems associated with herbicide use create the need for alternative weed control methods to be explored. Previous studies have shown the potential of mulch materials for controlling weeds in nurseries, but their use along with preemergence herbicides has not been extensively investigated. To compare the effects of different mulch materials and herbicides on Pennsylvania bittercress control, a full factorial designed greenhouse study was conducted. Three mulch treatments including no mulch, pine (Pinus sp.) bark, and rice (Oryza sativa) hulls were evaluated with three herbicide treatments, including water (i.e., no herbicide), isoxaben, and prodiamine applied at label rates. Twenty-five seeds of Pennsylvania bittercress were sown on the surface of each container and emergence (percent), coverage (square centimeters), seedhead number, and biomass (grams) were measured. The results showed that Pennsylvania bittercress in containers mulched with rice hulls had the lowest emergence throughout the experiment. For coverage, seedhead, and biomass parameters, Pennsylvania bittercress seeded in rice hulls treatments had significantly lower coverage, fewer seedheads, and lower biomass compared with those in nonmulched or pine bark treatments, regardless of herbicide treatment. With isoxaben and the water check, nonmulched treatments had the highest coverage/seedhead/biomass, whereas with prodiamine, Pennsylvania bittercress in pine bark mulched containers had the highest coverage/seedhead/biomass. In conclusion, applying rice hulls alone can provide better Pennsylvania bittercress control compared with isoxaben or prodiamine applied alone.

Dose–response screening of industrial hemp to herbicides commonly used in corn and soybean

AbstractRecent legalization of industrial hemp in the United States has led to increased interest among stakeholders to produce hemp for grain and fiber. However, owing to the lack of herbicides registered for use in hemp, producers are left with limited weed management strategies. Moreover, much of the agricultural land that could be used to cultivate industrial hemp may be prone to carryover of previously applied residual herbicides or physical drift from herbicides sprayed nearby. Industrial hemp sensitivity to herbicides is not well documented. Dose–response studies were conducted under controlled conditions in Madison, WI, screening two industrial hemp grain cultivars for tolerance to 44 preemergence and postemergence herbicides commonly used in corn and soybean. Treatments consisted of herbicides applied at 0×, 0.125×, 0.25×, 0.50×, 0.75×, 1×, 2×, and 4× the recommended maximum labeled rates based on soil type. Preemergence applications were delivered immediately after planting, whereas postemergence applications took place when hemp plants reached 5 to 10 cm in height. Nontreated plants served as the control and were used to estimate percent biomass reduction; dose–response curves were generated. Biomass reduction was >50% for rates under the suggested label rate for 23 preemergence and 21 postemergence herbicides tested. All herbicides tested resulted in >25% biomass reduction at the 0.125× rate, except for clopyralid applied preemergence and postemergence and saflufenacil applied preemergence. This is concerning, as the label rates are determined for effective weed control and the mitigation of herbicide resistance. Overall, these results indicate that industrial hemp is very sensitive to most herbicides tested. Growers should consider herbicide use history and surrounding crops when determining industrial hemp field selection to prevent significant plant injury due to herbicide carryover and drift. Further research into alternative methods of weed control will be vital to establishing hemp as a dominant crop once again.

Assessing the Weed-Suppressing Potential of Cotton Chromosome Substitution Lines Using the Stair-Step Assay.

Palmer amaranth is a problematic common weed species, especially in cotton. With the wide use of chemical herbicide and herbicide-tolerant transgenic cotton lines, Palmer amaranth populations have developed tolerance to commonly used herbicides. It is imperative to develop alternative weed control methods to slow the evolution of herbicide-resistant weed populations and provide new strategies for weed management. Eleven chromosome substitution (CS) cotton lines (CS-B26Lo, CS-T17, CS-B16-15, CS-B17-11, CS-B12, CS-T05sh, CS-T26Lo, CS-T11sh, CS-M11sh, CS-B22sh, and CS-B22Lo) were screened for weed-suppressing abilities in this study. The cotton lines were tested using the established stair-step assay. Height (cm) and chlorophyll concentration (cci) were measured for each plant in the system. The most significant variation in Palmer amaranth height reduction among the CS lines was observed 21 days after establishment. CS-B22sh (76.82%) and CS-T26Lo (68.32%) were most effective in reducing Palmer amaranth height. The cluster analysis revealed that CS-B22sh, and CS-T26Lo were clustered in one group, suggesting similar genetic potential with reference to Palmer amaranth growth and development. CS-B22sh showed novel genetic potential to control the growth and development of Palmer amaranth, a problematic weed in cotton fields. Future experimentation should implement more parameters and chemical testing to explore allelopathic interactions among CS lines and Palmer amaranth.

Vineyard weed control using alternative methods compared to glyphosate-based herbicide

In a two-year field experiment, six different weed control methods were studied. The methods were: use of the herbicide glyphosate (GL), use of herbicides based on acetic acid (AA), pelargonic acid (PA) and citrus essential oil (EO), mowing weeds with a thread trimmer (TT) and flaming of weeds with fire (FL). Alternative methods of weed control were significantly less effective than the use of herbicide glyphosate. Due to the lower efficiency of alternative methods, large yield losses have occurred, on average, 31 % at AA, 30.6 % at PA, 22.7 % at EO, 5.4 % at TT and 12.9 % at FL in two years. The cost of carrying out controls with alternative methods was significantly higher than the cost of GL. AA it was higher by 3.2-times, in PA by 7.1-times, in EO by 3.8-times, in TT by 3.8- times and in FL by 5.8-times on average in two years. To achieve a comparable control efficiency of GL, five applications of alternative preparations per year have to be performed, or four times mowing of weeds or five weed flaming operations per year.

Comparative Analysis of Microwave and Electric Arc as a New Method in Weed Control

The increase in the demand for organic production and the adverse effects of chemicals used in agriculture have brought non-chemical weed control methods to the fore. Among these methods, the most studied ones are microwave and electric arc methods. It has been determined in studies that microwaves and electric current, when applied at the correct power level and for sufficient time, biologically inactivate weeds, all kinds of unwanted plants and seeds. In this study, the mortality rates caused by microwave energy and electric current (arc) methods in some plants applied under laboratory conditions were compared. Studies have shown that the effectiveness of microwave and electric arc methods depends on the selected current, voltage, power level and exposure time. It is thought that the electric arc method is easier and more economical in terms of application in the field than the microwave method. Another purpose of this study is to remind agricultural policy makers and decision makers of the importance of alternative weed control methods and to ensure that they make policies in this direction.

Comparative Analysis of Microwave and Electric Arc as a New Method in Weed Control

The increase in the demand for organic production and the adverse effects of chemicals used in agriculture have brought non-chemical weed control methods to the fore. Among these methods, the most studied ones are microwave and electric arc methods. It has been determined in studies that microwaves and electric current, when applied at the correct power level and for sufficient time, biologically inactivate weeds, all kinds of unwanted plants and seeds. In this study, the mortality rates caused by microwave energy and electric current (arc) methods in some plants applied under laboratory conditions were compared. Studies have shown that the effectiveness of microwave and electric arc methods depends on the selected current, voltage, power level and exposure time. It is thought that the electric arc method is easier and more economical in terms of application in the field than the microwave method. Another purpose of this study is to remind agricultural policy makers and decision makers of the importance of alternative weed control methods and to ensure that they make policies in this direction.

Sustainable Organic Corn Production with the Use of Flame Weeding as the Most Sustainable Economical Solution

Flame weeding is an alternative method of weed control. Essentially, it is a supplement to other physical and mechanical processes used in organic production. Weed control costs have a large share of the total cost of crop production. This study aimed to investigate hand weed hoeing’s cost-effectiveness, accompanied by inter-row cultivation and flame weeding applied in organic maize production using two different machines to determine the economically best solution. For this purpose, the prototype flame weeder and commercial flame-weeding machinery were used. Designed primarily for smaller fields, the prototype flame weeder was equipped with a cultivator and a 70 kg propane bottle. Commercial Red Dragon flame weeder, fitted with an 800 kg propane tank and featuring no cultivation implements, is designed for larger areas. The analysis has shown that hand hoeing produced a higher yield (8.3 t/ha in total), but it contributed significantly to the production costs. The costs per hectare decreased when the prototype flame weeder and the commercial Red Dragon flame weeder were used compared to hand hoeing. More beneficial economic impacts were recorded when the prototype flame weeder was used (489.39 €/ha) than in applying the Red Dragon flame weeder (456.47 €/ha). The efficacy of flame weeding is somewhat limited and could be enhanced by additional hand hoeing, if the effect of the machine in terms of weeding is observed. However, the analysis has shown that, in this case, investments in additional hand hoeing are not economically justified because the operating costs incurred therein (168 €/ha) were not met by a yield increase of 500 kg/ha, i.e., a surplus revenue of 100 €/ha. Moreover, the economic impacts of flame weeding would be considerably more significant in larger fields.

Promising directions for the creation and use of technical means for weed control in the system of organic farming

Annotation Purpose. Reduction of labor costs for the production of organic vegetable products through the creation and use of new methods and techniques for weed control. Methods. Monographic, analytical, abstract-logical, structural modeling, design and manufacture of alternative technical means for the implementation of effective methods of weed control in the system of organic farming. Results. The main alternative methods and technical means for weed control in the system of organic farming in the world and in Ukraine are identified. Currently, alternative methods of weed control are weed control by flame, hot water and steam, and electropulse weed control. In fire cultivation, when the soil heating temperature does not exceed 70 °C, proteins in weed plants are damaged in the “thread” stage. In phase 4–6 the leaves, at the same temperature, destroy up to 90 %, and in the later phase of development – up to 75 % of weeds. Conclusions. An analysis of research and publications has shown that the use of known mechanical, thermal and electropulse weed control methods in various technological operations for growing crops will allow effective weed control in organic farming without the use of chemicals. The high-precision navigation system developed in the NSC “IAEE”, which is capable of carrying out a machine-tractor unit at a predetermined trajectory with a deviation of ±2 cm, will solve the problem of combating weeds in the ranks of vegetables and ingun crops in the system of organic farming. Keywords: organic farming, fire cultivation, weed control, steam and hot water, electropulse action.

Alelopatska svojstva biljni ekstrakata kao potencijalnih bioherbicida

Weeds are constant companions of plant production. For their control chemical substances, ie herbicides are used. In addition to a number of properties, the use of herbicides has numerous consequences, for the living world and for the environment, as well. Considering their negative effects, there is a need to find alternative methods of weed control. In recent decades, numerous researches have been done within the framework of biologically and eco-friendlier acceptable ways of controlling various pests, including weeds. Bioherbicides are compounds that contain microorganisms (such as bacteria or fungi), products of their metabolism, or plant extracts that have an effect on certain weed species. In this paper, the application of plant extracts that show allelopathic effects, as potential bioherbicides, in modern agricultural production, will be discussed.

COVER CROPS AS A WEED CONTROL METHOD AND THEIR EFFECT ON THE INITIAL GROWTH OF A Tectona grandis L.f. PLANTATION

Tectona grandis L.f. (teak), is one of the most used tropical species in commercial reforestation projects. Weed control is a common activity within these plantations. The objective of the study was to evaluate the effect of cover crops in weed control and the initial growth of a young teak stand in the southern part of Costa Rica. We used a randomized complete blocks design with three replications and seven treatments: a) control (without weed control), b) chemical weed control, c) manual weed control, d) cover crop Canavalia ensiformis , e) cover crop Vigna radiata , f) mix between Vigna radiata and Pueraria phaseloides, g) cover crop Crotalaria juncea . In addition, we calculated total costs for all treatments. All species exceeded 60% ground coverage, with C. juncea and V. radiata being the best performers. Although all cover crops had higher height values than the other treatments, only C. ensiformis had a significant effect on height growth at 6 months of age. Manual weed control was the most economical treatment. Based on the results obtained, we concluded that the cover crops can be used as an alternative method of weed control without affecting the growth of the trees.

Chemical composition and phytotoxic activity of Lippia origanoides essential oil on weeds

Studies in the area of allelopathy in agriculture have increased due to search on alternative methods of weed control compared to conventional herbicides. Thus, the objective of this work was to evaluate the chemical composition and phytotoxicity of the Lippia origanoides essential oil on weeds of the species Bidens subalternans, Euphorbia heterophylla and Macroptilium lathyroides. The essential oil was extracted from the leaves of L. origanoides by means of hydrodistillation and diluted in the concentrations of 0.01 to 1%. The chemistry composition was determined by a gas chromatograph coupled with a mass spectrometry. Phytotoxic activity was evaluated in pre and post-emergence by tests of germination, seedling growth, chlorophyll content and cellular respiration. The results demonstrated an essential oil rich in monoterpenes, mainly oxygenated, with camphor as the major compound. In general, both germination and seedling development were entirely inhibited by essential oil, decreasing with increasing concentrations. The concentrations 0.5 and 1.0% totally inhibited the germination of B. subalternans, but did not affect the germination of M. lathyroides. The essential oil sprayed on the weed leaves had no effect on chlorophyll content but was able to induce visible injuries such as necrosis and chlorosis. Only the cellular respiration of E. heterophylla was affected by the essential oil. All the phytotoxic effects observed are due to the high content of monoterpenes in the essential oil, mainly the oxygenates, and also the concentration used. Therefore, the L. origanoides essential oil have bioherbicidal potential for the tested species.

Leaf extracts of cultivated cardoon as potential bioherbicide

Increasing concerns about negative herbicides effects on the environment and the growing interest in organic agriculture demand for alternative weed control methods. This work aims to evaluate the phytotoxicity of different cultivated cardoon (Cynara cardunculus L. var. altilis DC.) leaf extracts on seed germination of four weeds (Amaranthus retroflexus L., Portulaca oleracea L., Stellaria media (L.) Vill., and Anagallis arvensis L.) commonly found in Mediterranean Basin, and to identify the compounds responsible for the extracts’ inhibitory activity. The extracts were obtained from dried, lyophilized and fresh leaves treated with three different solvents: water, methanol and ethanol. Citric acid was added to each solvent to check if the yield extract could be affected by pH modification. All extracts showed inhibitory effects on seed germination and mean germination time in all weeds, compared to control. The ethanolic extracts obtained by lyophilized leaves induced completely inhibition of seed germination in all weeds. Good results were also observed by using dried leaves, representing a valid alternative to lyophilized ones in terms of cost management. The HPLC analysis revealed that major compounds were caffeoylquinic acids, followed by flavones (apigenin and luteolin derivatives) and by the sesquiterpene lactone cynaropicrin. These results indicate that cultivated cardoon leaf extracts could present a good potential bioherbicide.

Using energy requirements to compare the suitability of alternative methods for broadcast and site-specific weed control

AbstractThe widespread use of herbicides in cropping systems has led to the evolution of resistance in major weeds. The resultant loss of herbicide efficacy is compounded by a lack of new herbicide sites of action, driving demand for alternative weed control technologies. While there are many alternative methods for control, identifying the most appropriate method to pursue for commercial development has been hampered by the inability to compare techniques in a fair and equitable manner. Given that all currently available and alternative weed control methods share an intrinsic energy consumption, the aim of this review was to compare methods based on energy consumption. Energy consumption was compared for chemical, mechanical, and thermal weed control technologies when applied as broadcast (whole-field) and site-specific treatments. Tillage systems, such as flex-tine harrow (4.2 to 5.5 MJ ha−1), sweep cultivator (13 to 14 MJ ha−1), and rotary hoe (12 to 17 MJ ha−1) consumed the least energy of broadcast weed control treatments. Thermal-based approaches, including flaming (1,008 to 4,334 MJ ha−1) and infrared (2,000 to 3,887 MJ ha−1), are more appropriate for use in conservation cropping systems; however, their energy requirements are 100- to 1,000-fold greater than those of tillage treatments. The site-specific application of weed control treatments to control 2-leaf-stage broadleaf weeds at a density of 5 plants m−2 reduced energy consumption of herbicidal, thermal, and mechanical treatments by 97%, 99%, and 97%, respectively. Significantly, this site-specific approach resulted in similar energy requirements for current and alternative technologies (e.g., electrocution [15 to 19 MJ ha−1], laser pyrolysis [15 to 249 MJ ha−1], hoeing [17 MJ ha−1], and herbicides [15 MJ ha−1]). Using similar energy sources, a standardized energy comparison provides an opportunity for estimation of weed control costs, suggesting site-specific weed management is critical in the economically realistic implementation of alternative technologies.

Fungal metabolites as a natural source of herbicide: a novel approach of weed management

Weeds are undesirable vegetation directly or indirectly inferring with human welfare. Conventional methods of weed control have failed due to one or other reason. Herbicide-resistant weeds are the main problem in weed control due to the number of weed biotypes resistant to herbicides that constantly increases by the continuous use of the same products for years. Development of alternative weed control methods is needed to help decrease reliance on herbicide use. Biological weed control is an alternative option for weed problems, particularly in agriculture and forestry. It is based on the use of natural enemies, particularly insects and pathogens to control weeds, as a sustainable, low cost and more environmentally acceptable method of weed control. One of the approaches to biological weed control using fungal phytotoxin applied in similar ways to conventional herbicides. Fungal phytotoxins are natural secondary metabolites produced by plant pathogenic fungi during host–pathogen interactions. They have received considerable particular attention for elucidating disease etiology, and consequently to design strategies for disease control. Due to wide differences in their chemical structures, these toxic metabolites have different ecological and environmental roles and mechanisms of action. This review aims at summarizing the studies on the possible use of fungal phytotoxin as a lucrative, novel source of secondary phytotoxic herbicidal compounds for management of broad spectrum, noxious and pernicious weeds.