Intensive Use Of Herbicides Research Articles

Advances in Nanotechnology for Sustainable Agriculture: A Review of Climate Change Mitigation

Currently, one of the main challenges is the mitigation of the effects of climate change on the agricultural sector. Conventional agriculture, with the intensive use of herbicides and pesticides to control weeds and pests, and the improper use of mineral fertilizers, contributes to climate change by causing increased greenhouse gases and groundwater pollution. Therefore, more innovative technologies must be used to overcome these problems. One possible solution is nanotechnology, which has the potential to revolutionize the conventional agricultural system. Active nanoparticles can be used both as a direct source of micronutrients and as a delivery platform for bioactive agrochemicals to improve crop growth, yield, and quality. The use of nanoparticle formulations, including nano-pesticides, nano-herbicides, nano-fertilizers, and nano-emulsions, has been extensively studied to improve crop health and shelf-life of agricultural products. Comprehensive knowledge of the interactions between plants and nanoparticles opens up new opportunities to improve cropping practices through the enhancement of properties such as disease resistance, crop yield, and nutrient use. The main objective of this review is to analyze the main effects of climate change on conventional agricultural practices, such as the use of pesticides, herbicides, and fertilizers. It also focuses on how the introduction of nanoparticles into conventional practices can improve the efficiency of chemical pest control and crop nutrition. Finally, this review examines in depth the last 10 years (2014–2024) of scientific literature regarding the use of nanoparticles in agriculture to mitigate the effects of climate change.

Genetic diversity of Sinapis arvensis L. (wild mustard) in Türkiye determined by microsatellite markers

Wild mustard (Sinapis arvensis L.) is a self-fertilizing weed species that exerts negative impacts on wheat production and herbicides are intensively used to manage it. Cross-fertilization may lead to genetic differentiation in this species. Therefore, this study investigated genetic diversity among wild mustard populations collected from wheat fields across various regions in Türkiye. Genetic variation was evaluated using 5 simple sequence repeat (SSR) markers in populations collected from 30 different locations. Populations were analyzed using UPGMA (unweighted pair group method with arithmetic mean) and principal component analysis (PCA). The mean genetic diversity (GD) and polymorphism information content (PIC) values were 0.752 and 0.844, respectively. High genetic variability was recorded among populations within geographic locations. The populations were categorized into two major groups by UPGMA. There was no apparent geographic isolation among tested populations, which displayed a high degree of variability. The primary source of this variability is thought to be the adaptability of wild mustard seeds dispersed through various methods across diverse locations. Despite being a predominantly self-pollinating species, wild mustard may also employ some cross-pollination mechanisms. In conclusion, SSR markers proved useful in determining genetic diversity in outcrossing species, especially where no prior genotypic information is available. The study suggests that genetic diversity is maintained in wild mustard populations even with rotational farming practices and intensive use of herbicides.

Planting season alters the interference of weeds in the common bean

The common bean has social, economic, culinary, and environmental relevance. Considering its low competitive capacity and the intensive use of herbicides, methods such as planting time can help in weed management. To determine the effect of the planting season on controlling weeds affecting common beans, an experiment was conducted during the summer planting and another in winter planting . For that seven incrementing periods were implemented: 0-10, 0-20, 0-30, 0-40, 0-50, 0-60 and 0-80 days after bean emergence with coexistence of weeds and the same periods with control of weeds, which established 14 treatments in four repetitions, under a random block design. Weeds were analyzed using a phytosociological method and their dry mass with yield examined by regression. The non-linear regression analysis determined the pre-interference period (PIP), the critical period for interference prevention (CPIP) and the total interference prevention period (TIP). The relevant species were Nicandra physaloides, Digitaria nuda and Raphanus raphanistrum. The TIP was similar in both planting seasons. The CPIP was 38 and 33 days in summer planting and winter planting, respectively. The PIP had six more days in winter planting compared to summer planting. The higher dry mass in weeds reduced yield by 14.7 % in winter planting, in relation to the summer planting, but the reduction was faster in this season. Winter planting conferred a certain competitive advantage to the crop over some weed species, thus it could be suggested planting common bean in that season

Screening of Herbicides in Transplanted Finger Millet [Eleusine coracana (L.) Gaertn

Background: Weeds smother the finger millet due to crop’s slow growth during the initial stages which reduces the yield substantially by 5-70%. Intensive use of herbicides is gaining popularity among the farmers now a days due to its effectiveness in controlling weeds, timeliness and reduced cost. Methods: The current field experiment was conducted at Tamil Nadu Agricultural university during kharif season, 2021 under irrigated condition with twelve herbicide treatments laid out in Randomized Complete Block Design (RCBD) with three replications. Result: Pre-emergence application of pyrazosulfuron ethyl 15 g ha-1 significantly reduced the total weed density and total weed dry weight at 90 days after transplanting over all the other herbicides used. This treatment also considerably improved the plant parameters such as plant height, total number of tillers, plant dry matter production, Grain and stover yield and yield parameters such as productive tillers, ear head weight of transplanted finger millet which was statistically followed by the application of pendimethalin 750 g ha-1 as pre-emergent spray. Similar trend was followed in case of net returns and B: C ratio. while lower plant parameters were observed with the application of tembotrione 12 g ha-1.

Reductive Dehalogenation of Herbicides Catalyzed by Pd0NPs in a H2-Based Membrane Catalyst-Film Reactor.

More food production required to feed humans will require intensive use of herbicides to protect against weeds. The widespread application and persistence of herbicides pose environmental risks for nontarget species. Elemental-palladium nanoparticles (Pd0NPs) are known to catalyze reductive dehalogenation of halogenated organic pollutants. In this study, the reductive conversion of 2,4-dichlorophenoxyacetic acid (2,4-D) was evaluated in a H2-based membrane catalyst-film reactor (H2-MCfR), in which Pd0NPs were in situ-synthesized as the catalyst film and used to activate H2 on the surface of H2-delivery membranes. Batch kinetic experiments showed that 99% of 2,4-D was removed and converted to phenoxyacetic acid (POA) within 90 min with a Pd0 surface loading of 20 mg Pd/m2, achieving a catalyst specific activity of 6.6 ± 0.5 L/g-Pd-min. Continuous operation of the H2-MCfR loaded with 20 mg Pd/m2 sustained >99% removal of 50 μM 2,4-D for 20 days. A higher Pd0 surface loading, 1030 mg Pd/m2, also enabled hydrosaturation and hydrolysis of POA to cyclohexanone and glycolic acid. Density functional theory identified the reaction mechanisms and pathways, which involved reductive hydrodechlorination, hydrosaturation, and hydrolysis. Molecular electrostatic potential calculations and Fukui indices suggested that reductive dehalogenation could increase the bioavailability of herbicides. Furthermore, three other halogenated herbicides─atrazine, dicamba, and bromoxynil─were reductively dehalogenated in the H2-MCfR. This study documents a promising method for the removal and detoxification of halogenated herbicides in aqueous environments.

Effects of different application methods of spent coffee grounds on weed growth

AbstractThe extensive and intensive use of herbicides has resulted in the spread of herbicide-resistant weeds in many crop production systems; therefore, it is imperative to devise new organic weed control methods. Recently, the application of spent coffee grounds (SCG) in agricultural fields has been found to inhibit plant growth and germination and is thus considered a potentially effective weed control measure. This study aimed to evaluate the effects of different amounts and methods of SCG application on weed growth through field experiments. The field experiments were conducted in an upland field converted from a paddy in western Japan. The results show that the plow-in application of over 10 kg m−2 of SCG and mulching application of 20 kg m−2 decreased the weed dry weight compared with the control. In addition, the growth of weed species of families other than Gramineae, such as wingleaf primrose-willow and horseweed, was not significantly affected by SCG application. Weed species of families other than Gramineae are dominant in some upland fields. Hence, the inhibitory effect of SCG on weeds may be lower in original upland fields than in the upland field converted from paddy field that was investigated in the present study. Overall, this study demonstrated that the plow-in application of 10 kg m−2 of SCG every 4 mo was effective for weed control in an upland field converted from a paddy field. Because SCG worked against grass weeds under the specific conditions in this study, it would be valuable to explore other potential applications of this novel means of weed control.

Sulfonylurea Herbicide-Resistant Study on Broadleaf Weeds in The Lowland Rice Production Center in West Java, Indonesia

Most rice growers in Indonesia use herbicides for weed control. However, intensive use of herbicides can lead to the weeds to become resistant to the chemicals. The objective of this study was to determine the resistance status of weeds Ludwigia octovalvis, Sphenoclea zeylanica, Monochoria vaginalis in lowland rice in West Java, Indonesia. The study was started by planting three species of weeds, L. octovalvis, S. zeylanica, M. vaginalis, which were then treated with metsulfuron-methyl and penoxsulam herbicides. The study was conducted from January to May 2020 at Cikabayan Experimental Greenhouse, IPB University. The experiment was arranged in a randomized complete block design with four replications. The first factor was the origin of weeds, exposed weeds (Karawang and Subang), and not exposed to herbicides (Bogor); the second factor was the rates of the herbicide, i.e., 0, 2.5, 5, 10, 20, 40, 80 and 160 g. ha-1 for metsulfuron- methyl, and 0, 50, 100, 200, 400, 800, 1600, and 3200 ml.ha-1 for penoxsulam. The results showed that based on the resistance ratio, S. zeylanica and M. vaginalis from Karawang and Subang, and L. octovalvis from Subang, indicated a low resistance to metsulfuron-methyl, L. octovalvis from Karawang was still sensitive to metsulfuron-methyl. L. octovalvis, S. zeylanica, and M. vaginalis from Karawang and Subang were still sensitive to penoxsulam herbicides. This information would be useful to develop a strategy of weed management for important food crops.

​​Improved Herbicide Efficacy through Sole and Sequential Application of Herbicides for Higher Productivity of Urdbean (Vigna mungo) in Indian Semi-arid Tropics

Background: Weeds are major factor that leads to increase crop-weed competition and adversely effects of on growth, quality and yield of urdbean during kharif season. In urdbean the critical period for crop weed competition was the first 25-30 days; yields can be reduced by 50-90%, if weeds were not controlled during this period. As a result, successful weed management strategies to achieve increased growth and yield. Due to the ease, lower cost, timeliness and success controlling weeds, the progressive transformation of agriculture involving intensive use of herbicides has gained traction in recent years. Methods: During kharif season 2019, a field experiment was undertaken at the Agricultural Research Station of Ummedganj, Kota, comprising ten weed management strategies, laid out in a randomised complete block design with three replications. Result: Two hand weedings at 20 and 40 DAS recorded significantly lower weeds dry matter, higher weed control efficacy, ultimately culminating in improved yield attributes and yield, compared to weedy check. This treatment was at par with pendimethalin 30% EC @ 1 kg a.i. ha-1 fb propaquizafop 2.5% w w-1 @ 33.3 g a.i. ha-1 + imazethapyr 3.75% w w-1 (pre mix) ME @ 50 g a.i. ha-1 at 20 DAS resulting in significantly higher pods plant-1 (13.67), seeds pod-1 (6.33), test weight (28.47 g), grain (827 kg ha-1), straw (1393 kg ha-1), biological (2221 kg ha-1) and harvest index (37.26%) of urdbean over the other chemical based treatment.

Impact of Achillea moschata Wulfen on germination and growth of weed species Echinochloa oryzoides (Ard.) Fritsch and Lolium multiflorum Lam

Weeding is a practice of primary importance both in conventional agriculture where the intensive use of herbicides can represent a significant environmental risk and in organic farming where this practice is prohibited. Therefore, the need to identify alternative means of controlling weeds is evident. In this respect, allelopathy proves to be a useful tool to be integrated with conventional agronomic techniques for the management of infesting flora. In this work, we investigated the phytotoxic potential of Achillea moschata Wulfen (Asteraceae) against Echinochloa oryzoides (Ard.) Fritsch and Lolium multiflorum Lam., two noxious plants for crops such as rice and wheat. Preliminary anti-germination assays were carried out in controlled conditions by testing both the powder (0.25 g) and the aqueous extract (1%, 10% and 20%) from the A. moschata aerial parts. The obtained results showed that the powder was more effective than the extract in inhibiting seed germination (up to –81.6% vs –48.8% at 20% concentration) and seedling development (up to –99.4% vs –75.9% at 20% concentration) of both target species, although L. multiflorum was more susceptible than E. oryzoides to treatments. Furthermore, the chemical composition of the two used matrices was characterized by Solid-Phase Microextraction (SPME) sampling technique and Gas Chromatograph/Mass spectrometer (GC/MS) analyses. Camphor (25.8% and 49.9%) and 1,8 cineole (25.9% and 20.7%) were the main constituents in the samples, followed by bornyl acetate (6.7%) in the powder and fragranol (10.5%) in the aqueous extract.

Effect of Weed Management Practices on Weed Dynamics, Nutrient Depletion, Productivity and Profitability of Summer Mungbean (Vigna radiata) under Zero Tillage Condition

Background: Weeds are prime factor that adversely effects on growth, quality and yield of mungbean during summer and rainy season. Being a short duration crop, it faces heavy weed competition right from the early growth stages to harvesting. The critical period of crop weed competition in mungbean was initial 25-30 days, yield may be reduce up to 50-90% if weeds not manage at this stage. Hence, there is a need to find out the successful weed management strategies to realize higher growth and yield. The progressive transformation of agriculture concerning intensive use of herbicides is gaining status in recent years due to easy, lower cost, timeliness and successful controlling weeds. Therefore, keeping above information in view, the present study was undertaken to assess the effect of different weed management practices in summer mungbean under zero tillage condition to find out the better weed management, higher productivity and profitability.Methods: In this field-laboratory investigation during summer season, 2019, different herbicides were applied to manage weeds in mungbean. Eight treatments were applied based on various application windows. In the field and laboratory, the collected samples were determined for crop weed competition, yield attributes, yields and net returns. Result: The results revealed that weed free treatment was recorded lowest weed population at 30 DAS and harvest (1.8 and 2.9), weed dry weight (1.1 and 1.9g) and highest weed control efficiency (96.3 and 94.9%) followed by Pendimethalin (PE) fb one HW and Shaked (Propaquizafop + Imezathyper) application. The similar results also observed in nutrients removed by weeds. Among yield attributes, weed free treatment recorded the longest pod length, no. of pods/plant, no. of seeds/pod and test weight (7.9, 21.0, 9.7 and 43.0g, respectively) which was at par with Pendimethalin (PE) fb one HW and Shaked (Propaquizafop + Imezathyper) application. The magnitude of seed yield was increased under weed free (10.1 q/ha) and Shaked (Propaquizafop + Imezathyper) (9.5 q/ha) treatments by 127.9 and 113.8%, respectively over weedy check. Application of Shaked (Propaquizafop + Imezathyper) recorded highest net returns (Rs 55,079/ha) and B: C (2.8) over rest of the treatments. It can concluded that application of Shaked (Propaquizafop + Imezathyper) @ 2 L/ha at 20 DAS recommended for better weed control, higher yield and net returns of summer mungbean under zero tillage condition.

Leaching of 2,4-d and atrazine herbicides in red-yellow latosol

The intensive use of herbicides has increased the possibility of environmental contamination and the accumulation of pesticide residues in soil and water. This work aimed to evaluate the leaching potential of 2,4-D and atrazine herbicides in red yellow Latosol with a clayey texture. The experimental design was entirely randomized, in factorial 5x3 (five doses of each herbicide for three soil depths). The doses used were 1.25, 2.50, 6.25 and 12.50 L ha-1 for the 2.4-D herbicide and 2.25, 4.50, 11.25 and 22.50 L ha-1 for the atrazine herbicide (plus absolute witnesses). The herbicides were applied in buried pvc tubes to the soil and after accumulated rainfall of 87 mm, cucumber was grown as a bio indicator plant. The plant phytotoxicity, plant height, dry mass accumulation and leaf area where the evaluations were performed at 21 days after the sowing of the cucumber were analyzed. The 2.4-D herbicide didn`t present significant difference between treatments for the plant phytotoxicity variable, however, there was difference between treatments for plant height and dry mass. For leaf area, the difference was observed only for soil depths. Atrazine herbicide also showed no difference between treatments for plant phytotoxicity, but there was a difference between treatments and soil depths for the other variables. Under the conditions evaluated, 2,4-D and atrazine herbicides can leach into clayey soil regardless of the dose used and can reach up to 30 cm depth.

Herbicide-resistant weeds in turfgrass: current status and emerging threats

AbstractHerbicide-resistant weeds pose a severe threat to sustainable vegetation management in various production systems worldwide. The majority of the herbicide resistance cases reported thus far originate from agronomic production systems where herbicide use is intensive, especially in industrialized countries. Another notable sector with heavy reliance on herbicides for weed control is managed turfgrass systems, particularly golf courses and athletic fields. Intensive use of herbicides, coupled with a lack of tillage and other mechanical tools that are options in agronomic systems, increases the risk of herbicide-resistant weeds evolving in managed turfgrass systems. Among the notable weed species at high risk for evolving resistance under managed turf systems in the United States are annual bluegrass, goosegrass, and crabgrasses. The evolution and spread of multiple herbicide resistance, an emerging threat facing the turfgrass industry, should be addressed with the use of diversified management tools. Target-site resistance has been reported commonly as a mechanism of resistance for many herbicide groups, though non–target site resistance is an emerging concern. Despite the anecdotal evidence of the mounting weed resistance issues in managed turf systems, the lack of systematic and periodic surveys at regional and national scales means that confirmed reports are very limited and sparse. Furthermore, currently available information is widely scattered in the literature. This review provides a concise summary of the current status of herbicide-resistant weeds in managed turfgrass systems in the United States and highlights key emerging threats.

Incidence of multiple herbicide resistance in annual bluegrass (Poa annua) across southeastern Australia

AbstractAnnual bluegrass (Poa annua L.) is a problematic annual weed in established turf where the intensive use of herbicides has resulted in the evolution of herbicide resistance. In 2017, 31 populations of P. annua suspected to be resistant to herbicides commonly used to control this weed in turf were collected from golf courses across southeastern Australia to check the resistance status to different herbicide groups. All populations were found to be resistant to multiple turf herbicides. Dose–response experiments confirmed resistance to propyzamide, simazine, rimsulfuron, foramsulfuron, endothall, and pinoxaden. Levels of resistance to rimsulfuron (>56-fold), foramsulfuron (>19-fold), endothall (>7-fold), and pinoxaden (>4.3-fold) compared with the susceptible population were high, but levels of resistance to propyzamide (>2-fold) and simazine (>2-fold) were lower. Considerable variation in resistance to endothall and pinoxaden was observed among the populations of P. annua. Target-site resistance was confirmed for acetolactate synthase and acetyl-CoA carboxylase inhibitors, but not for photosystem II and microtubule assembly inhibitors. This study documented the extensive resistance to herbicides in P. annua from turf in Australia. Three of the populations investigated exhibited multiple resistance to herbicides from five mechanisms of action. The identification of multiple-resistant P. annua on several golf courses is a serious concern for turf managers.

A combination of rice cultivar mixed-cropping and duck co-culture suppressed weeds and pests in paddy fields

Industrial agriculture with intensive use of herbicides and pesticides has resulted in a great reduction of biodiversity and negative environmental impacts on rice paddy fields. Biodiversity-based farming systems can improve production efficiency and sustainability, with fewer negative environmental impacts and lower use of external inputs. Previous studies have reported that both the rice-duck co-culture systems and mixed-cropping systems with different rice cultivars can suppress weed communities and control harmful pests. However, little is known about the effects of an integration of mixed-cropping with different rice cultivars and rice-duck co-culture on weed communities and pests in paddy fields. Four combinations with three replications of each treatment were employed, half with and half without ducks in paddy fields, which were compared with mono-cropping systems of the five rice cultivars. After two-season experiments, we found that species richness and diversity of weed communities in the mixed-cropping with rice-duck co-culture (MCDC) systems were significantly lower than those in the mono-cropping systems. The abundance of rice leaf roller in the MCDC systems was also significantly lower than that in the mono-cropping systems. Our findings indicated that the biodiversity-based farming would be an environmentally friendly approach to control weeds and rice leaf roller without using herbicides or pesticides in paddy fields, and hence to produce more safe, healthy, and high-quality rice and duck meat.

Bioconcentrations of herbicides used in sugarcane crops in tilapia (Oreochromis niloticus) and the risk for human consumption

The practice of intensive herbicide use in the sugarcane industry has a high risk of compromising the quality of the water and the organisms that live there due to losses through runoff, leaching and other processes. In this work, the dynamics of four herbicides present in three different mixtures were evaluated through their incorporation and elimination in the muscle tissue of tilapia (Oreochromis niloticus). The highest mean values of bioconcentration factors were 1.730 for ametryn, 0.891 for tebuthiuron, 0.322 for hexazinone and 4.783 for diuron. Diuron presented the highest risk regarding the consumption of tilapia fillets by the population. However, considering that the fish would reach maximum levels of diuron when exposed to extremely high concentrations, an individual weighing 70 kg would need to ingest approximately 1.5 kg of this food product to surpass the acceptable daily intake of 0.007 mg kg−1 body weight. It was concluded that the risk of injury to the population consuming tilapia fillets from fish exposed to herbicides in water arising from sugarcane activities is very low.According to the risk estimation performed in this work, which is substantiated by the assumptions of the World Health Organization and the International Life Sciences Institute, there is a low risk of injury to the population consuming tilapia fillets from fish exposed to water containing herbicides in concentrations arising from sugarcane activities. However, as the risk was estimated from laboratory conditions, caution should be taken where herbicide applications are carried out with high frequency near water bodies, as the consumption of fish from these areas is quite common.

Controlled Release of Herbicides Using Nano-Formulation: A Review

The intensive use of herbicides and other classes of chemicals products, in agricultural practices has resulted in serious environmental impact causing increasing level of herbicide residues in natural water, soil, and foodstuffs. Controlled release nano-formulation of herbicides in which the herbicides are incorporated in a nanosized matrix or carrier before application will be an excellent alternative over the conventional methods of herbicides application usually employed to control pathogens, weeds and several pests, thereby limiting the amount of the active ingredient available for unwanted processes. This review presents a better approach using nanotechnology for controlled release formulation of herbicides in agriculture.

Terbuthylazine interferes with iron nutrition in maize (Zea mays) plants

Many chemicals, including herbicides, are routinely applied to crops for weed management and food production improvement. However, the intensive use of herbicides could lead eventually to a great environmental threat due to their persistence and accumulation in the ecosystems and contamination of soils. Furthermore, the possible effect of these chemicals on nutrient uptake and assimilation in crops has only recently been discussed. The present study aimed at understanding the effect of the herbicide terbuthylazine (TBA), a herbicide commonly applied to control weeds in leguminous species and triazine tolerant crops, on the capability of maize plants to cope with iron (Fe) shortage. The application of 2 and 5 mg L−1 TBA caused a significant reduction of root Fe concentration. This reduction might be attributed to a decreased release of phytosiderophores, which in turn could be ascribed to a reduced sulfur assimilation. Results provide evidence that TBA impairs Fe uptake and accumulation in non-target plants most likely interacting with sulfur-assimilating enzymes [ATP sulfurylase and O-acetylserine(thiol)lyase].

Intensive herbicide use has selected for constitutively elevated levels of stress-responsive mRNAs and proteins in multiple herbicide-resistant Avena fatua L.

Intensive use of herbicides has led to the evolution of two multiple herbicide-resistant (MHR) Avena fatua (wild oat) populations in Montana that are resistant to members of all selective herbicide families available for A. fatua control in US small grain crops. We used transcriptome and proteome surveys to compare constitutive changes in MHR and herbicide-susceptible (HS) plants associated with non-target site resistance. Compared to HS plants, MHR plants contained constitutively elevated levels of differentially expressed genes (DEGs) with functions in xenobiotic catabolism, stress response, redox maintenance and transcriptional regulation that are similar to abiotic stress-tolerant phenotypes. Proteome comparisons identified similarly elevated proteins including biosynthetic and multifunctional enzymes in MHR plants. Of 25 DEGs validated by RT-qPCR assay, differential regulation of 21 co-segregated with flucarbazone-sodium herbicide resistance in F3 families, and a subset of 10 of these were induced or repressed in herbicide-treated HS plants. Although the individual and collective contributions of these DEGs and proteins to MHR remain to be determined, our results support the idea that intensive herbicide use has selected for MHR populations with altered, constitutively regulated patterns of gene expression that are similar to those in abiotic stress-tolerant plants. © 2017 Society of Chemical Industry.

Differentiation of Life-History Traits among Palmer Amaranth Populations (Amaranthus palmeri) and Its Relation to Cropping Systems and Glyphosate Sensitivity

Palmer amaranth’s ability to evolve resistance to different herbicides has been studied extensively, but there is little information about how this weed species might be evolving other life-history traits that could potentially make it more aggressive and difficult to control. We characterized growth and morphological variation among 10 Palmer amaranth populations collected in Florida and Georgia from fields with different cropping histories, ranging from continuous short-statured crops (vegetables and peanut) to tall crops (corn and cotton) and from intensive herbicide use history to organic production. Palmer amaranth populations differed in multiple traits such as fresh and dry weight, days to flowering, plant height, and leaf and canopy shape. Differences between populations for these traits ranged from 36% up to 87%. Although glyphosate-resistant (GR) populations collected from cropping systems including GR crops exhibited higher values of the aforementioned variables than glyphosate-susceptible (GS) populations, variation in traits was not explained by glyphosate resistance or distance between populations. Cropping system components such as crop rotation and crop canopy structure better explained the differences among populations. The higher growth of GR populations compared with GS populations was likely the result of multiple selection forces present in the cropping systems in which they grow rather than a pleiotropic effect of the glyphosate resistance trait. Results suggest that Palmer amaranth can evolve life-history traits increasing its growth and reproduction potential in cropping systems, which explains its rapid spread throughout the United States. Furthermore, our findings highlight the need to consider the evolutionary consequences of crop rotation structure and the use of more competitive crops, which might promote the selection of more aggressive biotypes in weed species with high genetic variability.

European eel (Anguilla anguilla) plasma biochemistry alerts about propanil stress.

Propanil stress response in the eel (Anguilla anguilla) was examined. Eels were exposed to 3.16 mg/L for 72 hr and allowed to recover for 96 hr. Plasma levels of cortisol, lactate dehydrogenase (LDH), alkaline phosphatase (AP), aspartate aminotransferase (AST), cholesterol, triglycerides, glucose, ammonium, lactate, albumin, and total proteins as well as electrolytes (chloride, sodium, potassium, calcium and phosphorus) were determined. As a consequence of exposure, cortisol, AP, AST, and LDH increased. A hyperglycemic condition, together with hyperlactemia, hypoalbuminemia, hypoproteinemia, hypercholesterolemia and hypertriglycemia was registered. Ammonium increased during exposure concomitantly to hyponatremia, hypochloremia, hypocalcemia, hypophosphatemia, and hypokatremia. During recovery, chloride, sodium, potassium, ammonium, albumin and LDH normalized. At the end of the experiment, fish still exhibited hyperglycemia and hyperlactemia. Hypercalcemia was observed. Cholesterol, triglycerides, AP, and AST did not recuperate. These findings are important for assessing potential risks for areas where fish are grown near intensive herbicide use (i.e., paddy fields).