ABSTRACT The herbicides glyphosate and 2,4-D are widely used to control weeds in various crops. The rubber tree crop is exposed to these molecules, which can interfere with its establishment. This study aimed to assess the effects caused by the drift of glyphosate, 2,4-D, and the combination of both, in different proportions corresponding to 0, 4, 8, 16, 32, and 64% of the recommended dose (1,440 and 804 g a·e·ha-1 of glyphosate and 2,4-D, respectively). The characteristic symptoms when 2,4-D was present in the drift began with wilting and shriveling of young leaves and, at the highest doses, quickly progressed to chlorosis, shoot epinasty, and edge necrosis, while mature leaves showed a brown color, culminating in a high rate of fall. The effects of glyphosate were intensified after leaf flushing, which occurred 120 days after its application and resulted in long, narrow, twisted leaves in a spiral shape and deformed shoots. Drift above 32% from the combination of glyphosate and 2,4-D resulted in a high mortality rate, while 16% damaged growth and resulted in the death of some plants. The results indicate that drift from the combination of glyphosate and 2,4-D intensifies the symptoms of phytotoxicity in rubber trees, with drift above 8% being harmful. For the herbicides applied alone, there was full recovery of the plants in the drift of up to 16%, so it is important to avoid the drift of these herbicides in the management of weeds in the rubber tree crop.

ABSTRACT Mapping resistant populations makes it possible to identify the evolution and dispersal of resistance cases, providing important information for control-related decision making. This study aimed to identify and map herbicide-resistant sourgrass (Digitaria insularis) populations in Brazilian regions. The results showed no glufosinate resistance, with 485 samples (96.6%) classified as putative resistant to glyphosate, while nine (1.8%) and five (1%) were considered putative resistant to haloxyfop and clethodim, respectively. Two samples were deemed putative resistant to three herbicides (glyphosate, haloxyfop, and clethodim). One of the samples characterized as a control failure for all three herbicides was used on the dose-response curve. This biotype was identified as glyphosate-resistant, with low-level resistance to clethodim and haloxyfop. Based on C50, resistance factors of 10.96, 3.26, and 3.15 were identified for glyphosate, clethodim, and haloxyfop, respectively. Mapping sourgrass resistance is vital to understand and ensure the early identification and quantification of the frequency of these plants. cases controlrelated related making herbicideresistant herbicide Digitaria insularis regions 48 96.6% 966 96 6 (96.6% glyphosate 1.8% 18 1 8 (1.8% 1% (1% respectively (glyphosate clethodim. . clethodim) doseresponse dose response curve glyphosateresistant, glyphosateresistant resistant, glyphosate-resistant lowlevel low level C50 C 1096 10 10.96 326 3 26 3.26 315 15 3.1 plants 4 96.6 9 (96.6 1.8 (1.8 (1 C5 109 10.9 32 2 3.2 31 3. 96. (96. 1. (1. ( 10. (96 (9

The present study analyzed the chemical composition and phytotoxic activity of Artemisia lancea essential oil (EO). Gas chromatography-mass spectrometry (GC-MS) results showed the presence of 55 compounds, representing 82.36% of the entire EO, with eucalyptol (18.7%) being the most abundant constituent. Phytotoxic bioassay results indicated that the EO (concentration ranging from 0.25-5 mg mL−1) inhibited the growth of Amaranthus retroflexus and Setaria viridis. Root length of A. retroflexus and S. viridis were reduced with the increasing concentration of the EO, especially when the EO was applied at 1-5 mg mL−1. When treated with 1-5 mg mL−1 EO, shoot length of A. retroflexus and S. viridis were also significantly suppressed. The half maximal inhibitory concentration (IC50) values for inhibiting root and shoot growth of A. retroflexus by the EO were 0.284 and 0.246 mg mL−1; for S. viridis, the EO showed IC50 values of 0.44 and 0.262 mg mL−1 for root and shoot inhibition, respectively. The most promising findings were observed when A. lancea EO concentration reached 1 mg mL−1 and higher, which completely inhibited seed germination of A. retroflexus and S. viridis. These findings suggest A. lancea EO has potential as an eco-friendly bioherbicide for agricultural weed control. EO. . (EO) chromatographymass chromatography mass GCMS GC MS (GC-MS 5 compounds 8236 82 36 82.36 18.7% 187 18 7 (18.7% constituent 0.255 0255 0.25 0 25 0.25- mL1 mL A S 15 1- mL− suppressed IC (IC50 0284 284 0.28 0246 246 0.24 IC5 044 44 0.4 0262 262 0.26 inhibition respectively higher ecofriendly eco friendly control (EO 823 8 3 82.3 18.7 (18.7 255 025 0.2 2 (IC5 028 28 024 24 04 4 0. 026 26 82. 18. (18. 02 (IC (18 (1 (

ABSTRACT The search for more sustainable systems of rice cultivation, especially in relation to water use, has included the evaluation of more-efficient irrigation systems in addition to alternative water sources. The aim of this study was to conduct a phytosociological survey of weeds in rice crops irrigated by subsurface drip with different concentrations of treated dairy effluent, maintaining the soil moisture at saturation or field capacity. A pilot scale experiment was carried out in a protected environment using a randomised block design in a 5 x 2 factorial scheme, with four replications. The IAC 301 cultivar (Arborio rice) was chosen. The phytosociological surveys were carried out on four different dates, and considered the composition as well as the distribution of plant species in each of the applied treatments, using the importance value index (IVI) to evaluate the influence of each treatment. The results showed that cultivating irrigated rice, giving priority to water management, altered the ecology of invasive plants. Fourteen weed species were identified, distributed over 10 families. The effluent dose did not alter the incidence of invasive plants, and only at the final evaluation was there a reduction in the IVI value at effluent concentrations of 50% and 75%. For soil moisture, the highest IVI values occurred on the first two days of the survey under saturated conditions; this result was reversed closer to plant maturity, when the IVI values were higher at field capacity. cultivation use moreefficient efficient sources capacity scheme replications 30 Arborio chosen dates treatments (IVI treatment management plants identified 1 families 50 75 75% conditions maturity 3 7

ABSTRACT There is great interest in varieties with greater competitive ability against weeds. This can be facilitated by path analysis, which involves the statistical evaluation and interpretation of the relationship between yield and its components. In this analysis, the occurrence of multicollinearity results in inconsistent estimates of the coefficients, and overestimates of the direct effects of the explanatory variables on the response variable. The aim of this study was to identify the characteristics with the greatest direct effect on pod yield and green and dry bean yields in traditional cowpea varieties, evaluated in competition with weeds in two experiments. In addition, the presence of multicollinearity was investigated in the analyses. In Experiment-1, twelve varieties with the highest bean yields in a preliminary evaluation were assessed in a randomized block design with five replications. In Experiment-2, six varieties, selected in the preliminary evaluation, were assessed using two methods of weed management: three of the most productive and three of the least productive. Randomized blocks and split plots were used, with five replications. Multicollinearity, indicated by the number of conditions and the variance inflation values, was greater in Experiment-2. In the six cases under study (three yields x two experiments), the number of pods per plant had the greatest direct effect on yield. analysis components coefficients variable experiments addition analyses Experiment1, Experiment1 Experiment 1, 1 Experiment-1 replications Experiment2, Experiment2 2, 2 Experiment-2 management used Multicollinearity values Experiment2. 2. experiments, , experiments) Experiment-

ABSTRACT Several species of harmful grass weeds were voluntarily brought in by man, mainly with the specific purpose of produce forage. These species compete with crops for physical area and environmental resources, can host pests and diseases, and interfere on harvesting. This work aimed to evaluate in field conditions, the effects of different specific seed weight and sowing depths on the emergence of the species Urochloa brizantha cv. marandú. It was adopted a randomized blocks design with four replications and the treatments arranged in a 6 x 3 factorial scheme, with six sowing depths (1.0, 2.0, 4.0, 8.0, 12.0 and 16.0 cm) and three specific seed weight (low, medium, and high). The treatment effects were evaluated by seedling emergence in field. The marandu-grass seedlings emerged until 12 cm depth, regardless of specific seed weight and year. Sowing depths between 1.0 and 4.0 cm depth have promoted the greater percentage of emergence, and the lowest average time and speed index for emergence of seedlings on field, regardless of the specific seed weight. High-specific weight seeds resulted in greater percentage of emergence on field, speed and synchronicity index of emergence of marandú-grass seedlings. Sowing depths higher than 1.0 cm induces a delay on marandú-grass propagation. man forage resources diseases harvesting conditions cv marandú scheme 1.0, 10 1 0 (1.0 20 2 2.0 40 4 80 8 8.0 120 12. 160 16 16. low, low (low medium high. high . high) marandugrass marandu year 1. 4. Highspecific High marandúgrass propagation (1. 2. 8. (1 (

RESUMO Novas tecnologias desenvolvidas para controlar plantas daninhas nas lavouras surgiram nos últimos anos. Diante disso objetivou-se com o trabalho estudar a habilidade competitiva dos híbridos de milho 2B433 (Enlist®), Pioneer 30F53 (VYHR®), 13K288 PWE (Enlist®) e uma variedade convencional (não transgênica), com antecedentes biotecnológicos distintos, ao competir com leiteiro (Euphorbia heterophylla) e papuã (Urochloa plantaginea). O milho e os competidores foram estudados em diferentes proporções de plantas: 20:0; 15:5; 10:10; 5:15 e 0:20 plantas vaso-1 ou 100:0; 75:25; 50:50; 25:75 e 0:100% (cultura: planta daninha) em experimentos de série substitutiva. Aos 50 dias após a emergência das espécies foi determinado a eficiência fotossintética e de carboxilação, a concentração de CO2 no mesofilo foliar, além da área foliar e a massa seca da parte aérea das plantas. O milho híbrido 2B433 (Enlist®) apresentou melhor desempenho fisiológico e morfológico em relação à variedade convencional, e os híbridos 13K288 PWE (Enlist®) e 30F53 (VYHR®) quando em competição com leiteiro e papuã. O aumento da capacidade competitiva parece ser devido à maior área foliar e massa seca da parte aérea relatada para 2B433 (Enlist®). A capacidade competitiva apresentada pelos híbridos é distinta não se encontrando evidências de que o evento transgênico presente na cultura esteja afetando a habilidade competitiva. anos objetivouse objetivou B 2B43 Enlist®, Enlist Enlist® , F 30F5 VYHR®, VYHR VYHR® K 13K28 (Enlist® transgênica, transgênica transgênica) distintos Euphorbia heterophylla Urochloa plantaginea. plantaginea . plantaginea) 200 20 0 20:0 155 15 5 15:5 1010 10 10:10 515 5:1 020 0:2 vaso1 vaso 1 vaso- 1000 100 100:0 7525 75 25 75:25 5050 50:50 2575 25:7 0100% 0100 100% 0:100 (cultura daninha substitutiva carboxilação CO (VYHR® Enlist®. 2B4 30F 13K2 (Enlist 2 20: 15: 101 10:1 51 5: 02 0: 100: 752 7 75:2 505 50:5 257 25: 010 0:10 (VYHR 2B 13K 10: 75: 50: 01 0:1

ABSTRACT New technologies developed to control weeds in crops have flourished in recent years. Therefore, the objective of this work was to study the competitive ability of maize hybrids 2B433 (Enlist®), Pioneer 30F53 (VYHR®), and 13K288 PWE (Enlist®) and a conventional (non-transgenic) variety with a distinct biotechnological background when competing against wild poinsettia (Euphorbia heterophylla) and Alexandergrass (Urochloa plantaginea). Crops and competitors were studied in distinct plant proportions: 20:0, 15:5, 10:10, 5:15 and 0:20 plants per pot or 100:0, 75:25, 50:50, 25:75, and 0:100% (crop:weed) in replacement series experiments. Fifty days after emergence, the leaf area and aboveground dry mass were measured. Concomitantly, the photosynthetic and carboxylation efficiency and CO2 concentration were assessed in the leaf mesophyll. Maize hybrid 2B433 (Enlist®) showed better physiological and morphological performance compared to the conventional variety, and hybrids 13K288 PWE (Enlist®) and 30F53 (VYHR®) showed better performance when competing with wild poinsettia or Alexandergrass. The increased competitive ability seems to be due to the greater leaf area and aboveground dry mass reported for 2B433 (Enlist®). Therefore, the competitive ability presented by the hybrids was distinct, and we found no evidence that the transgenic event present in these hybrids affected their competitive ability. years Therefore B 2B43 Enlist®, Enlist Enlist® , F 30F5 VYHR®, VYHR VYHR® K 13K28 (Enlist® nontransgenic non (non-transgenic Euphorbia heterophylla Urochloa plantaginea. plantaginea . plantaginea) proportions 200, 200 20 0, 0 20:0 155, 155 15 5, 5 15:5 1010, 1010 10 10, 10:10 515 5:1 020 0:2 1000, 1000 100 100:0 7525, 7525 75 25, 25 75:25 5050, 5050 50 50, 50:50 2575, 2575 75, 25:75 0100% 0100 100% 0:100 cropweed crop weed (crop:weed experiments emergence measured Concomitantly CO mesophyll (VYHR® Enlist®. 2B4 30F 13K2 (Enlist 2 20: 1 15: 101 10:1 51 5: 02 0: 100: 752 7 75:2 505 50:5 257 25:7 010 0:10 (VYHR 2B 13K 10: 75: 50: 25: 01 0:1

RESUMO: Em geral, alelopatia pode ser definido como o processo biológico no qual um organismo produz metabolitos que alteram a germinação, o crescimento, a sobrevivência e a reprodução de outros organismos, influenciando a estabilidade de agroecossistemas. O colesterol, o mais abundante esterol isolado da alga vermelha marinha Plocamium brasiliense, foi estudado quanto ao seu potencial efeito inibitório na germinação de sementes, alongamento das radículas e desenvolvimento do hipocótilo das ervas daninhas Mimosa pudica (malicia) e Senna obtusifolia (mata-pasto). Colesterol foi isolado do extrato em Hexano por métodos cromatográficos. Durante 15 dias, os bioensaios de germinação foram realizados a 25 ºC e fotoperíodo de 12 horas, enquanto os bioensaio de alongamento da radícula e do hipocótilo foram realizados a 25 ºC e fotoperíodo de 24 horas. Posteriormente, placas de Petri de 9,0 cm de diâmetro foram revestidas de papelfiltro, e 25 sementes foram mantidas em câmaras de germinação, enquanto seis sementes pré-germinadas foram postas em placas de Petri por 2-3 dias. Após dez dias, a extensão da radícula e do hipocótilo foi medida. O potencial inibitório do colesterol foi avaliado a 5, 10, 15 e 20 ppm. Em ambas as ervas M. pudica e S. obtusifolia, foram afetadas significativamente pela ação do cholesterol alcançando maiores percentuais de inibição na germinação das sementes (50% e 33%, respectivamente), alongamento da radícula (68% e 60%, respectivamente) e desenvolvimento do hipocótilo (66% e 55%, respectivamente). Os efeitos inibitórios foram dose-dependentes em todos os experimentos, tendo efeitos alelopaticos mais acentuados a 20 ppm. RESUMO geral crescimento organismos agroecossistemas brasiliense malicia (malicia matapasto. matapasto mata pasto . (mata-pasto) cromatográficos 1 dias 2 horas Posteriormente 90 9 0 9, papelfiltro prégerminadas pré germinadas 23 3 2- medida 5 10 ppm M S 50% 50 (50 33 33% respectivamente, respectivamente , 68% 68 (68 60 60% 66% 66 (66 55 55% respectivamente. dosedependentes dose dependentes experimentos (mata-pasto (5 6 (6 (

ABSTRACT: In general, allelopathy can be defined as a biological process by which an organism produces one or more metabolites that can change the germination, growth, survival, and reproduction of other organisms, and thus influencing the stability of agroecosystems. Cholesterol is a very abundant sterol isolated from the marine red alga Plocamium brasiliense that has been studied regarding its potential inhibitory effects on seed germination, radicle elongation, and hypocotyl development of the weeds Mimosa pudica (malicia) and Senna obtusifolia (mata-pasto). Cholesterol was isolated from a hexane extract by chromatographic methods. Over a 15-day period, germination bioassays were performed at 25 ºC with a 12-h photoperiod. Radicle elongation and hypocotyl development were assayed at 25 ºC with a 24-h photoperiod. Later, Petri dishes 9.0 cm in diameter were coated with filter paper, and 25 seeds were placed in a germination chamber. Six pre-germinated seeds were placed in the Petri dish for 2-3 days. After 10 days, radicle and hypocotyl extensions were measured, and the inhibitory potential of cholesterol was assessed at 5, 10, 15, and 20 ppm. In both herbs, M. pudica and S. obtusifolia, they were significantly affected by the action of cholesterol, achieving higher percentages of inhibition in seed germination (50% and 33%, respectively), radical germination (68% and 60%, respectively), and hypocotyl development (66% and 55%, respectively). The inhibition effects were dose-dependent in all experiments, having more pronounced allelopathic effects at 20ppm. ABSTRACT general growth survival organisms agroecosystems malicia (malicia matapasto. matapasto mata pasto . (mata-pasto) methods 15day day 15 period 2 12h h 12 photoperiod 24h 24 Later 90 9 0 9. paper chamber pregerminated pre germinated 23 3 2- days 1 measured 5 ppm herbs M S 50% 50 (50 33 33% respectively, respectively , respectively) 68% 68 (68 60 60% 66% 66 (66 55 55% respectively. dosedependent dose dependent experiments 20ppm (mata-pasto (5 6 (6 (

Resumen Introducción. La percepción de que las plantas nativas de campos agrícolas no aportan nada bueno a los sistemas productivos y deben ser eliminadas en su totalidad ha provocado múltiples problemas agronómicos, ambientales y sociales en los agroecosistemas alrededor del mundo, tales como selección de plantas resistentes a herbicidas, contaminación de cuerpos de agua, pérdida de biodiversidad, aumento en las poblaciones de insectos plaga y afectación de la salud de trabajadores agrícolas debido al uso intensivo de herbicidas. Objetivo. Analizar el origen de las malezas en la agricultura, las características biológicas que las hacen perjudiciales para las actividades del ser humano y sus funciones ecológicas en el agroecosistema, así como proponer la aplicación del concepto de biodiversidad funcional para el manejo agroecológico de la vegetación en campos agrícolas. Desarrollo. En este momento de cambio hacia una producción agrícola con un menor uso de plaguicidas, el manejo de las malezas sigue siendo un gran reto. Para lograr que el manejo integrado de malezas avance hacia estrategias agroecológicas que permitan una reducción del uso de herbicidas es necesario promover las interacciones bióticas benéficas que regulan de forma natural a las malezas. El estudio y aplicación de la biodiversidad funcional en los agroecosistemas surge entonces como una necesidad para manejar la vegetación de forma tal que se minimicen los efectos negativos de las malezas en los cultivos y se maximicen los servicios agroecosistémicos de las arvenses. Conclusión. La diferenciación entre malezas y arvenses como parte de un manejo agroecológico de los sistemas de cultivo permitiría mantener un balance positivo entre productividad y biodiversidad en los agroecosistemas.

Abstract Introduction. The perception that native plants in agricultural fields do not contribute positively to productive systems and should be eliminated in their entirety has caused multiple agronomic, environmental and social problems in agroecosystems around the world, such as selection of herbicide-resistant plants, contamination of water bodies, loss of biodiversity, increase in pest insect populations, and impact on the health of agricultural workers due to the intensive use of herbicides. Objective. To provide basic information on the origin of weeds in agriculture, the biological characteristics that make them harmful to human activities, and their ecological functions in the agroecosystem, as well as to propose the application of the concept of functional biodiversity for the agroecological management of weeds in crop fields. Development. In this moment of change towards agricultural production with less use of pesticides, weed management is still a great challenge. To ensure that integrated weed management advances towards agroecological strategies that allow a reduction in the use of herbicides, it is necessary to promote the beneficial biotic interactions that naturally regulate weeds. The study and application of functional biodiversity in agroecosystems then emerges as a need to manage vegetation in such a way that the negative effects of weeds on crops are minimized and the agroecosystem services of weeds are maximized. Conclusion. The differentiation between weeds and segetal vegetation as part of an agroecological management of cropping systems would allow maintaining a positive balance between productivity and biodiversity in agroecosystems.

RESUMEN Los agroecosistemas del nordeste argentino forman comunidades vegetales importantes. Las arvenses de hábito trepador pueden tornarse malezas. El monitoreo y detección temprana de especies perjudiciales contribuye a prevenir infestaciones y son herramientas útiles para alcanzar una agricultura sustentable. El objetivo del presente trabajo fue reconocer, describir y diferenciar 12 especies de malezas en estadios juveniles, con el fin de facilitar el monitoreo y prevenir el enmalezamiento en cultivos de yerba mate, té, mandioca, batata, maní, arroz y girasol, en 8 diferentes localidades de las provincias de Misiones, Corrientes y Chaco. Se realizaron censos de vegetación en diversos cultivos de 8 localidades. De las malezas más importantes se cosecharon propágulos que fueron conservados en heladera a 6°C. Luego, las semillas y esquejes se colocaron en sustrato inerte, con humedad controlada y a temperatura ambiente en contenedores de plástico. Se utilizó un calibre digital y flexómetro estándar; las fotografías fueron tomadas con smartphone y cámara digital. Se obtuvieron plántulas de 12 especies, las cuales fueron observadas, descritas morfológicamente, ilustradas, mensuradas sus partes, registrando sus estados fenológicos iniciales e identificadas taxonómicamente. Se presenta un cuadro comparativo de las especies estudiadas, una clave dicotómica para poder reconocerlas en campo y las ilustraciones de los diferentes taxones. Las diferencias morfológicas en estado de plántulas y plantas jóvenes son importantes y suficientes para reconocer estas 12 especies en campo y poder así elegir estrategias MIM orientadas a la sustentabilidad de los agroecosistemas de la región del nordeste argentino.

ABSTRACT Agroecosystems in northeastern Argentina form important plant communities. Climbing weeds can become invasive. Monitoring and early detection of detrimental species can contribute to preventing infestations and are useful tools to achieve sustainable agriculture. The aim of the present study was to recognize, describe, and differentiate 12 weed species in juvenile stages. This was performed to facilitate monitoring and prevent weed invasion in yerba mate, tea, cassava, sweet potato, peanut, rice, and sunflower crops in 8 different locations in the provinces of Misiones, Corrientes, and Chaco. Vegetation surveys were carried out in different crops in 8 localities. Propagules were harvested from the most important weeds and stored in the refrigerator at 6°C. Subsequently, seeds and cuttings were placed in inert substrate with controlled humidity and at room temperature in plastic containers. A digital caliper and a standard flexometer were used. Likewise, photographs were taken with a smartphone and digital camera. Seedlings of 12 species were obtained, observed, morphologically described, illustrated, their parts were measured, their initial phenological stages were recorded, and they were taxonomically identified. A comparative table of the species studied, a dichotomous key for field recognition, and illustrations of the different taxa are presented. The morphological differences in seedling and young plant stages are important and sufficient to recognize these 12 species in the field and thus be able to choose IWM strategies aimed at the sustainability of agroecosystems in the northeastern region of Argentina.

RESUMEN La Ecorregión Litoral Central abarca una superficie de 26.310 km2, representando aproximadamente el 10 % de los pastizales utilizados para la producción ganadera. La Ecorregión presenta en áreas abiertas, un estrato herbáceo de poáceas, que son utilizados para la alimentación del ganado vacuno. La incidencia de malezas de la subfamilia Mimosoidea en estas áreas constituye una gran competencia para los pastizales debido a su crecimiento arbustivo espinoso o enmarañado que dificultan el acceso del ganado al forraje. El objetivo de este trabajo fue la identificación, descripción botánica, distribución de especies de la subfamilia Mimosoidea con incidencia dañina en los pastizales destinados a la producción ganadera en la Ecorregión Litoral Central del Paraguay. Para ello, se colectaron plantas de la subfamilia Mimosoidea en pastizales destinados a la producción ganadera, durante los meses de setiembre del año 2022 a enero del año 2023, georreferenciando las mismas. Las muestras fueron identificadas y depositadas en el Herbario FCQ, del Departamento de Botánica de la Facultad de Ciencias Químicas (FCQ) de la Universidad Nacional de Asunción (Material de Referencia). La identificación se realizó siguiendo las claves taxonómicas y por comparación con ejemplares de la colección botánica FCQ. Se tomaron fotografías de las especies y se elaboró una clave de la identificación. Se identificaron 7 especies de mimosas, pertenecientes a la subfamilia Mimosoidea, siendo 4 de ellas de porte arbustivo espinoso, 1 subarbustivo espinoso y 2 subarbustivos inermes, que constituyén una gran competencia para las pasturas.

ABSTRACT The Central Littoral Ecoregion covers an area of 26,310 km2, representing approximately 10% of the grasslands used for livestock production). The Ecoregion presents, in open areas, herbaceous layer of grasses, which are used for cattle feed. The incidence of weeds of the Mimosoidea subfamily in these areas, constitutes a great competition for grasslands due to their thorny or tangled shrub growth that hinders livestock access to forage. The objective of this work was the identification, botanical description, and distribution of species of the Mimosoidea subfamily with harmful incidence in grasslands intended for livestock production in the Central Coastal Ecoregion of Paraguay. To this end, plants of the Mimosoidea subfamily were collected in grasslands intended for livestock production, during the months of September 2022 to January 2023, georeferencing them. The samples were identified and deposited in the FCQ Herbarium, of the Department of Botany of the Faculty of Chemical Sciences (FCQ) of the National University of Asunción (Reference Material). The identification was carried out following the taxonomic keys and by comparison with specimens from the FCQ botanical collection. Photographs of the species were taken and an identification key was drawn up. Seven species of mimosa were identified, belonging to the subfamily Mimosoidea, 4 of which were spiny shrubby, 1 spiny sub-shrubby and 2 spineless sub-shrubs, which constituted a great competition for pastures.

ABSTRACT Although faba-bean (Vicia faba L.) is not a major crop in China, many farmers like to cultivate faba-bean in autumn as a fresh food or animal feed for next spring. However, no herbicides are available to control weeds in the faba-bean fields. Although prosulfocarb is a candidate herbicide, some farmers have reported that prosulfocarb can often cause harm to faba-bean. Our laboratory experiment results revealed that Tongcanxian No. 6, a faba-bean cultivar with large seeds, showed the lowest level of growth inhibition and Qidou No. 2, a faba-bean cultivar with small seeds, showed the highest level of growth inhibition when treated with 3960 and 7920 g ai ha-1 prosulfocarb. The growth inhibition rate of faba-bean was 0% when 3960 and 7920 g ai ha-1 prosulfocarb was sprayed within 6 d after sowing, indicating that prosulfocarb treatment should be applied as soon as possible after sowing. When the temperature exceeded 20 °C and soil moisture content exceeded 20%, it might have aggravated the phytotoxicity of ‘Tongcanxian No. 6’ and ‘Qidou No. 2’ caused by prosulfocarb. Two round of field experiments showed visually that the control effect of 3960 g ai ha-1 prosulfocarb on the total weeds exceeded 90% and safe to faba-bean at the same time. This study indicated that prosulfocarb can be safely used in faba-bean fields by improving agronomic methods, which can also provide a reference for weed management in faba-bean fields worldwide.

Abstract: Fodder beet is a crop of interest in the Norpatagonia Argentina, since it is used for feeding cattle in winter. Although it offers nutritional advantages and significant yields, its slow establishment and competition with weeds pose challenges to producers, and thus the application of herbicides is essential for proper crop management. The objective of this study was to evaluate the effect of replacing the pre-emergent herbicide S-metolachlor by pendimethalin on the establishment of fod- der beer. Pot and field experiments were carried out. The pot experiment consisted of 3 treatments of pre-emergent herbicides (PRE): S-metolachlor 1 L ha-1 (M) and pendimethalin in two doses: 4 and 6 L ha-1 (P4 and P6), and a post-emergent herbicide (POS): Betanal 1 L ha-1 (B). The field experiment was conducted using a split-plot design, with PRE (P4, P6 and M) as the main factor, and with and without POS (B) as the secondary factor. Crop emergence dynamics and weed control were evaluated by comparing richness, abundance and diversity between treatments. In the pot trial, treatment P4 showed crop emergence dynamics similar to the control treatment (T), being less phytotoxic than M. In both experiments, the treatments did not show significant differences in weed species richness, while P4 without POS was the treatment exhibiting the highest abundance and diversity of species. The replacement of M by P4 would be a suitable alternative for the establishment of fodder beet crop accompanied by a post-emergence herbicide.

Resumen: La remolacha forrajera es un cultivo de interés en la Norpatagonia Argentina, ya que es usada para la alimentación del ganado bovino en invierno. Aunque ofrece ventajas nutricionales y rendimientos significativos, su lenta implantación y la competencia con malezas presenta algunas dificultades para los productores, por lo que la aplicación de herbicidas es fundamental para el adecuado manejo del cultivo. El objetivo de esta investigación fue evaluar el efecto de sustituir el herbicida preemergente S-metalocloro por pendimetalin en la implantación del cultivo. Se llevaron a cabo experimentos en maceta y de campo. El experimento en macetas consistió en tres tratamientos de herbicidas preemergentes (PRE): S-metalocloro 1 L ha-1 (M) y pendimetalin en dos dosis: 4 y 6 L ha-1 (P4 y P6); y un herbicida posemergente (POS): Betanal 1 L ha-1 (B). El experimento de campo se realizó usando un diseño de parcelas divididas donde el factor principal fue PRE (P4, P6 y M), y el factor secundario fue POS: con y sin (B). Se evaluó la dinámica de emergencia del cultivo y el control de malezas, comparando riqueza, abundancia y diversidad entre tratamientos. En el experimento en macetas, el tratamiento P4 mostró una dinámica de emergencia del cultivo similar al tratamiento testigo (T), siendo menos fitotóxico que M. En ambos experimentos, los tratamientos no evidenciaron diferencias significativas en riqueza de especies de malezas, mientras que P4 sin POS fue el que presentó mayor abundancia y diversidad. La sustitución de M por P4 sería una alternativa adecuada para la implantación del cultivo de remolacha forrajera, acompañada de un herbicida de posemergencia.

Abstract Introduction: Borreria spinosa is a herbaceous plant considered a weed in agricultural crops, although it also has potential in apiculture. Despite its agronomic importance, its cytogenetic and palynological traits are poorly known. Objective: To do the cytogenetic characterization of B. spinosa, describe the morphology of its pollen grains, and estimate their potential viability. Methods: We collected plant material in Santiago del Estero, Argentina, in May 2017 and used classical methods (8-hydroxyquinoline and Farmer for mitosis and meiosis; viability with Müntzing; pollen morphology with nonacetolysed and acetolysed techniques, and SEM). Results: B. spinosa has a chromosome number of 2n = 56, with a karyotype of 46 m + 10 sm. Meiotic abnormalities mainly include chromosomes outside the equatorial plate, lagging chromosomes, and cytomixis. Pollen grains are small to medium-sized, suboblate to oblate-spheroidal, with a viability of 70%. This is a tetraploid species, most chromosomes are metacentric or submetacentric; and it has irregular meiotic behavior and cytomixis, with concomitant low viability in pollen grains. Conclusion: In B. spinose, pollen grains have similar characteristics to other species of the genus Borreria.

Resumen Introducción: Borreria spinosa es una planta herbácea considerada maleza en cultivos agrícolas, aunque también presenta potencial en la producción apícola. A pesar de su importancia agronómica, sus rasgos citogenéticos y palinológicos son poco conocidos. Objetivo: Caracterizar citogenéticamente a B. spinosa, describir la morfología de sus granos de polen, y estimar su viabilidad potencial. Métodos: Recolectamos material vegetal en Santiago del Estero, Argentina, en mayo de 2017 y utilizamos métodos clásicos (8-hidroxiquinolina y Farmer para mitosis y meiosis; viabilidad con Müntzing; morfología del polen con técnicas no acetolizadas y acetolizadas, y MEB). Resultados: B. spinosa tiene un número cromosómico de 2n = 56, con un cariotipo de 46 m + 10 sm. Las anomalías meióticas incluyen principalmente cromosomas fuera de la placa ecuatorial, cromosomas rezagados y citomixis. Los granos de polen son de pequeños a medianos, suboblatos a oblato-esferoidales, con viabilidad del 70%. Es tetraploide, la mayoría de los cromosomas son metacéntricos o submetacéntricos; y tiene comportamiento meiótico irregular y citomixis, con baja viabilidad concomitante del polen. Conclusión: En B. spinosa, los granos de polen tienen características similares a otras especies del género Borreria.

Abstract Introduction. Weeds are one of the main problems in agricultural productivity due to their interactions with crops, such as alelopatic effects on germination. Objective. To evaluate the allelopathy of kikuyo grass (Cenchrus clandestinus) on the germination of beans (Phaseolus vulgaris L.) variety ICA Cerinza. Materials and methods. The study was conducted at the Quality Control Laboratory of the Universidad de Pamplona, Central Campus, Pamplona, Norte de Santander, Colombia, from May to August 2022. To each experimental unit (Petri dishe) with 12 been seeds, 6 mL of kikuyo aqueous extract (leaf, stem, and root) at three concentrations (1, 2.5, and 5 %), plus a control (0 %), were added, totaling 12 treatments. From day 0 to 12, the number of germinated seeds (NGS) was recorded, and the germination rate index (GRI) and germination index (IG) were calculated. The biomolecular profile of the aqueous extract was determined using the Fourier-transform spectroscopy. A completely randomized experimental design with a factorial arrangement (3x4), with repeated measures in each experimental unit, was employed. The intersuject factors were the organ type and concentration, while the intrasubject factor was the evaluation time (12 days). Results. Significant differences (p<0.001) were observed for NSG among treatments due to the concentration of the aqueous extract, as well as for IG, while GRI depended on the organ (p<0.05) and concentration (p<0.001), both negatively affected as the concentration increased. The infrared spectrum of the extract determined the presence of polyphenols, nitriles, and siloxanes. Conclusión. C. clandestinus affected NGS, GRI, and GI of P. vulgaris, with an allelopathic effect of the leaf aqueous extract at higher concentrations. Polyphenols, nitriles, and siloxanes associated with allelopathic effects were identified in the aqueous extracts.

Resumen Introducción. Las arvenses son uno de los principales problemas en la productividad agrícola, debido a interacciones con el cultivo, como efectos alelopáticos sobre la germinación. Objetivo. Evaluar la alelopatía del pasto kikuyo (Cenchrus clandestinus) en la germinación de frijol (Phaseolus vulgaris L.) variedad ICA Cerinza. Materiales y métodos. El estudio se realizó en el laboratorio de Control de Calidad de la Universidad de Pamplona, Campus Central, Pamplona, Norte de Santander, Colombia, en mayo-agosto 2022. A cada unidad experimental (caja de Petri) con doce semillas de frijol se le agregó 6 mL de extracto acuoso de kikuyo (hoja, tallo y raíz) en tres concentraciones (1, 2,5 y 5 %), más un testigo (0 %), para un total de doce tratamientos. En el lapso de 0 a 12 días, se registró el número de semillas germinadas (NSG), se calculó el índice de tasa de germinación (ITG) y el índice de germinación (IG), y se determinó el perfil biomolecular del extracto acuoso mediante la técnica de espectroscopia transformada de Fourier. Se utilizó un diseño experimental completamente al azar con arreglo factorial (3x4), con medidas repetidas en cada unidad experimental. Los factores intersujetos fueron el tipo de órgano y concentración, y el factor intrasujeto fue el tiempo (12 días) de evaluación. Resultados. Se observaron diferencias significativas (p<0,001) para NSG entre tratamientos por efecto de la concentración del extracto acuoso al igual que para IG, mientras que ITG dependió del órgano (p<0,05) y la concentración (p<0,001); ambos fueron afectados de forma negativa conforme aumentó la concentración. En el espectro infrarrojo del extracto se determinaron polifenoles, nitrilos y siloxanos. Conclusión. C. clandestinus afectó NSG, el ITG e IG de P. vulgaris, con efecto alelopático del extracto acuoso de hoja en mayor concentración. En los extractos acuosos se determinaron polifenoles, nitrilos y siloxanos, asociados a efecto alelopático.