RESUMO

A significant level of yield losses in the vegetable and fruit farms are attributed to the weed populations of the area. This study was conducted for eighteen months during 2019-2020 to assess the presence of various weed families, related species, and their densities in the vegetable (CROP A) and fruit (CROP B) farms of Taif, Saudi Arabia. During the study, fourteen and ten weed families were noted in the vegetable and fruit farms of the studied area, respectively. Poaceae family weeds (729) were significantly higher in numbers followed by the families Asteraceae (414), Chenopodiaceae (338), and Gisekiaceae (153). In the vegetable farms, two weed species of the family Poaceae including Setaria viridis (437) and Eleusine indica ssp (277) were present in the higher numbers followed by Chenopodium murale (166) of the Chenopodiaceae family. In the fruit farms, the weed species Cynodon dactylon of the family Poaceae represented the highest weed density (172) followed by Gisekia pharnaceoides L. species (153) of family Gisekiaceae and Portulaca oleracea (59) belonging to the family Portulacaceae. The vegetable and fruit farms of the Taif region face severe weed pressure that affects the cultivated crops. This study depicts a comprehensive picture of weed diversity and density in the vegetable and fruit farms of the area. The results of this study will be beneficial in developing effective weed management practices for better crop production.

Assuntos

RESUMO

The objective was to evaluate weed phytosociology and similarities between crop management systems in the Chapadões region. The experiment was conducted at in agricultural area located in the municipality of Chapadão do Sul, MS, during the 2016/17 harvest. Three crop managements strategies were used: (1) cotton/soybean/Urochloa, (2) millet/soybean/millet and (3) millet/soybean/crotalaria. A phytosociological survey of weeds was carried out during soybean cultivation and cover crops growth, in succession. The evaluation area for each management strategy was 0.5 ha. Soybean surveys were carried out in October and January, while the cover crop surveys were performed in February and May. The relative frequency (RF), relative density (RD), relative abundance (AR), and relative importance (RI) of weeds, Venn diagram, and Jaccard and Sorenson similarity indices were evaluated. The management area represented by the cotton/soybean/Urochloa rotation had fewer weed species than others. The species Cenchrus echinatus, Digitaria insularis, Digitaria sanguinalis, Eleusine indica and Commelina benghalensis had the highest phytosociological indeces among the monocotyledons. Attention is required for managing the dicotyledons Amaranthus deflexus, Conyza canadensis and Senna obtusifolia despite their low indices because of herbicide resistant cases. The highest indeces of similarity were found between managements areas 2 and 3, which did not rely on cotton cultivation prior to soybeans.

Assuntos

RESUMO

Currently, in Argentina 368 species of true ferns (i.e. Polypodiopsida class) are distributed throughout the country, however, only four of them have been mentioned until now as weeds and ruderal species. The goal of this work was to generate an update of weedy ferns from Argentina, including morphology, distribution, and type of weed according to their impact on natural habitats and/or human activities. All Argentinian fern species were analyzed based on references, herbarium specimens, and field trips. As a result of our study 25 species were recorded from Argentina and classified as segetal, ecological, or aquatic weeds, and ruderal and/or toxic species. Current taxonomic identity, diagnostic characters, origins, habitats, geographical distribution, common names, and impact and potential risks were indicated by species. In addition, we provide a dichotomous key to species, presence of these species in southern South American countries, as well as and photographs in natural habitat. This work represents the first review on native and exotic ferns from Argentina that cause an impact on human activities or disturbe native habitats. The results provide information for the development of weed management tools and priority areas to implement them.

Assuntos

RESUMO

Currently the weed species are a resource to conserve. The objective was to evaluate the ethnobotanical perception of the peasants about the weed flora in farms of suburban agriculture in Santiago de Cuba, Cuba. An ethnobotanical study was developed and the percentage of known species, percentage of species per management action and the percentage of weed species with potential utility was determined. The spectrum of use, the categories of use and the species richness by category were also taken into account. The weed species found in each of the farms were identified by at least 60% of the producers conferring more than 70% of this flora potential utilities such as medicinal, animal feed and agricultural. Although different forms of management for these species were identified, more than 40% are eliminated regardless of the potential benefits that productive systems can bring to this.

Actualmente las especies arvenses son un recurso a conservar. El objetivo fue evaluar la percepción etnobotánica de los campesinos sobre la flora arvense en fincas de la agricultura suburbana en Santiago de Cuba, Cuba. Se desarrolló un estudio etnobotánico y se determinó el porcentaje de especies conocidas, porcentaje de especies por acción de manejo y el porcentaje de especies arvenses con utilidad potencial. También se tuvo en cuenta el espectro de uso, las categorías de uso y la riqueza de especies por categoría. Las especies arvenses que se encuentran en cada una de las fincas fueron identificadas por al menos el 60% de los productores confiriéndoles a más del 70% de esta flora utilidades potenciales como medicinal, alimento animal y agrícola. Aunque se identificaron diferentes formas de manejo para estas especies, más del 40% resultan eliminadas independientemente de los beneficios potenciales que puedan aportar a estos sistemas productivos.

Assuntos

RESUMO

The stunting disease, incited by chrysanthemum stunt viroid (CSVd), has become a serious problem in chrysanthemum production areas worldwide. Here we identified 46 weed species from chrysanthemum fields in two producing regions of the State of São Paulo, Brazil. The mechanical inoculation of these weeds with a Brazilian CSVd isolate revealed that this viroid was able to infect 17 of these species, in addition to chrysanthemum, tomato and potato. Plants of Oxalis latifolia and chrysanthemum naturally infected with CSVd were found in chrysanthemum fields in Colombia, which is the first CSVd report in that country. Therefore, weeds have the potential to act as reservoirs of CSVd in the field. These results are the first reports of experimental CSVd infection in the following species: Amaranthus viridis, Cardamine bonariensis, Chamaesyce hirta, Conyza bonariensis, Digitaria sanguinalis, Gomphrena globosa, Helianthus annuus, Lupinus polyphyllus, Mirabilis jalapa, Oxalis latifolia, Portulaca oleracea and Catharanthus roseus. The phylogenetic analyses of the CSVd variants identified herein showed three groups with Brazilian CSVd variants distributed in them all, which suggests that Brazilian CSVd isolates may have different origins through successive introductions of infected germplasm of chrysanthemum in Brazil.

Assuntos

RESUMO

The new technology of sugarcane planting, known as one-eye-set seedlings, offer a high standard of plant health and vegetative vigor. However, there are no reports in the literature that evaluate the weed competition with one-eye-set sugarcane seedlings, and the periods in which weed communities need to be controlled in this system. Two interference experiments were conducted in field conditions. The first experiment determined the periods of weed interference of an infesting community predominated by Ipomoea hederifolia and Merremia aegyptia in sugarcane. In the second experiment, these same species competed with plants of the same sugarcane cultivar. Productivity and qualitative aspects of production were evaluated. The critical period of interference prevention in one-eye-set sugarcane system was 103 days, with weed community interference starting at 35 days and lasting until 138 days after planting. Weed coexistence during the entire sugarcane cycle reduced productivity by 60% and affected qualitative characteristics such as the total reducing sugars. Both species affected the vegetative development of the crop, mainly the tillering. I. hederifolia plants developed ahead of the M. aegyptia plants but in late evaluations the interference caused by M. aegyptia (77%) was greater (P<0.01) than that caused by I. hederifolia (72%).

Assuntos

RESUMO

Objetivou-se avaliar os efeitos da planta daninha Solanum sisymbrifolium (joá-bravo) sobre o número e as características de perfilhos de Urochroa decumbens cv. Basilisk em pasto sob lotação contínua com bovinos. Foram avaliados dois locais do mesmo pasto, sendo um próximo, localizado a 0,5 m do caule principal da planta daninha, e outro distante, onde não havia ocorrência desta planta em 2,0 m de raio, por meio da quantificação do número, peso e morfologia dos perfilhos. O delineamento foi inteiramente ao acaso com três repetições. No local distante da planta daninha houve maior densidade populacional de perfilhos com desfolhação e sem o meristema apical. Os números de perfilhos basais e aéreos foram menores próximo da planta daninha. Este local também apresentou menores números de perfilhos vegetativos, reprodutivos, vivos, mortos e totais, quando comparado ao local distante da planta daninha. Os pesos de perfilhos vegetativos e reprodutivos foram maiores no local próximo do que no distante da planta daninha. Os perfilhos próximos da planta daninha apresentaram maiores comprimento do pseudocolmo e de lâmina foliar, superior número de folha viva e inferior número de folha pastejada em relação aos distantes. A ocorrência da planta S. sisymbrifolium ocasiona variabilidade espacial da vegetação no pasto de U. decumbens cv. Basilisk...

The objective of this study was to evaluate the effects of the weed Solanum sisymbriifolium (sticky nightshade) on the number and characteristics of Urochloa decumbens cv. Basilisk tillers in pasture continuously stocked by cattle. Two sites of the same pasture were evaluated, one site located close (0.5 m) to the main stalk of the weed and the other located at a distance where no weed was growing within a radius of 2.0 m. The number, weight and morphology of the tillers were evaluated in a completely randomized design with three repetitions. At the site distant from the weed, a higher population density of defoliated tillers without apical meristem was observed. The number of basal and aerial tillers was smaller close to the weed plant. This site was also characterized by smaller numbers of vegetative, reproductive, live, dead and total tillers when compared to the site distant from the weed plant. The weight of vegetative and reproductive tillers was higher at the site close to the weed plant. Tillers close to the weed plant exhibited a greater length of the pseudostem and leaf blade, a larger number of live leaves, and fewer grazed leaves compared to distant tillers. The occurrence of S. sisymbriifolium results in spatial variability of vegetation in U. decumbens cv. Basilisk pasture...

Assuntos

RESUMO

Objetivou-se avaliar os efeitos da planta daninha Solanum sisymbrifolium (joá-bravo) sobre o número e as características de perfilhos de Urochroa decumbens cv. Basilisk em pasto sob lotação contínua com bovinos. Foram avaliados dois locais do mesmo pasto, sendo um próximo, localizado a 0,5 m do caule principal da planta daninha, e outro distante, onde não havia ocorrência desta planta em 2,0 m de raio, por meio da quantificação do número, peso e morfologia dos perfilhos. O delineamento foi inteiramente ao acaso com três repetições. No local distante da planta daninha houve maior densidade populacional de perfilhos com desfolhação e sem o meristema apical. Os números de perfilhos basais e aéreos foram menores próximo da planta daninha. Este local também apresentou menores números de perfilhos vegetativos, reprodutivos, vivos, mortos e totais, quando comparado ao local distante da planta daninha. Os pesos de perfilhos vegetativos e reprodutivos foram maiores no local próximo do que no distante da planta daninha. Os perfilhos próximos da planta daninha apresentaram maiores comprimento do pseudocolmo e de lâmina foliar, superior número de folha viva e inferior número de folha pastejada em relação aos distantes. A ocorrência da planta S. sisymbrifolium ocasiona variabilidade espacial da vegetação no pasto de U. decumbens cv. Basilisk...(AU)

The objective of this study was to evaluate the effects of the weed Solanum sisymbriifolium (sticky nightshade) on the number and characteristics of Urochloa decumbens cv. Basilisk tillers in pasture continuously stocked by cattle. Two sites of the same pasture were evaluated, one site located close (0.5 m) to the main stalk of the weed and the other located at a distance where no weed was growing within a radius of 2.0 m. The number, weight and morphology of the tillers were evaluated in a completely randomized design with three repetitions. At the site distant from the weed, a higher population density of defoliated tillers without apical meristem was observed. The number of basal and aerial tillers was smaller close to the weed plant. This site was also characterized by smaller numbers of vegetative, reproductive, live, dead and total tillers when compared to the site distant from the weed plant. The weight of vegetative and reproductive tillers was higher at the site close to the weed plant. Tillers close to the weed plant exhibited a greater length of the pseudostem and leaf blade, a larger number of live leaves, and fewer grazed leaves compared to distant tillers. The occurrence of S. sisymbriifolium results in spatial variability of vegetation in U. decumbens cv. Basilisk pasture...(AU)

Assuntos

RESUMO

The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

Assuntos

RESUMO

O controle da população de plantas espontâneas através do uso de plantas de cobertura é prática tradicional e pode ser promovida durante o desenvolvimento vegetativo das espécies cultivadas ou após a sua dessecação. O objetivo do presente trabalho foi determinar a produtividade de matéria seca de culturas de cobertura semeadas em épocas distintas, em região de cerrado e identifi car a composição fl orística da comunidade de plantas daninhas presentes nestas áreas de produção. O experimento foi desenvolvido em condições de campo, no município de Selvíria, MS. Foi utilizado delineamento experimental em blocos casualizados contando com 10 tratamentos, sendo quatro culturas de cobertura: sorgo, crotalária, milheto, braquiária, e uma área em pousio; e duas épocas de semeadura, em 27/03/2008 e 23/04/2008. Para obtenção da produtividade de matéria seca dos tratamentos foi realizada coleta do material vegetal em 07/07/2008. A caracterização e estudo fi tossociológico da comunidade de plantas daninhas realizada em 20/10/2008. Entre os períodos de avaliação foi possível verifi car 19 espécies de plantas daninhas ocorrendo nas culturas de cobertura. De posse dos resultados obtidos pode-se concluir que a Brachiaria brizantha em condições de alta pluviosidade e altas temperaturas promove grande formação de matéria seca em curto período, sendo capaz de reduzir a população de plantas daninhas e que áreas em pousio são rapidamente infestadas, podendo competir diretamente com as culturas na sequência.(AU)

The population control of weeds with the use of cover crops is common practice and can be promoted during the vegetative growth of the sown crop or after its desiccation. The objective of this paper was to determine the dry matter yield of cover crops sown at different times in the Cerrado region and identify the fl oristic composition of the weed community present in this production area. The experiment was conducted in fi eld conditions in Selvíria, MS, with a randomized block design with 10 treatments and four cover crops: sorghum, sunnhemp, millet, pasture and fallow area, and two sowing dates, March 27th, 2008 and April 23th, 2008. Dry matter yield was collected on July 07th 2008. The characterization and phytosociological study of the weed community was held on October 20th, 2008. Nineteen species of weed were identifi ed in the cover. The results showed that the pasture (Brachiaria brizantha) under heavy rainfall and high temperatures produced large areas of dry matter within a short period of time. Thus, the cover crops are able to reduce the weed population and the fallow area gets infested quickly and can compete directly with crops in succession.(AU)

Assuntos

RESUMO

O controle da população de plantas espontâneas através do uso de plantas de cobertura é prática tradicional e pode ser promovida durante o desenvolvimento vegetativo das espécies cultivadas ou após a sua dessecação. O objetivo do presente trabalho foi determinar a produtividade de matéria seca de culturas de cobertura semeadas em épocas distintas, em região de cerrado e identifi car a composição fl orística da comunidade de plantas daninhas presentes nestas áreas de produção. O experimento foi desenvolvido em condições de campo, no município de Selvíria, MS. Foi utilizado delineamento experimental em blocos casualizados contando com 10 tratamentos, sendo quatro culturas de cobertura: sorgo, crotalária, milheto, braquiária, e uma área em pousio; e duas épocas de semeadura, em 27/03/2008 e 23/04/2008. Para obtenção da produtividade de matéria seca dos tratamentos foi realizada coleta do material vegetal em 07/07/2008. A caracterização e estudo fi tossociológico da comunidade de plantas daninhas realizada em 20/10/2008. Entre os períodos de avaliação foi possível verifi car 19 espécies de plantas daninhas ocorrendo nas culturas de cobertura. De posse dos resultados obtidos pode-se concluir que a Brachiaria brizantha em condições de alta pluviosidade e altas temperaturas promove grande formação de matéria seca em curto período, sendo capaz de reduzir a população de plantas daninhas e que áreas em pousio são rapidamente infestadas, podendo competir diretamente com as culturas na sequência.

The population control of weeds with the use of cover crops is common practice and can be promoted during the vegetative growth of the sown crop or after its desiccation. The objective of this paper was to determine the dry matter yield of cover crops sown at different times in the Cerrado region and identify the fl oristic composition of the weed community present in this production area. The experiment was conducted in fi eld conditions in Selvíria, MS, with a randomized block design with 10 treatments and four cover crops: sorghum, sunnhemp, millet, pasture and fallow area, and two sowing dates, March 27th, 2008 and April 23th, 2008. Dry matter yield was collected on July 07th 2008. The characterization and phytosociological study of the weed community was held on October 20th, 2008. Nineteen species of weed were identifi ed in the cover. The results showed that the pasture (Brachiaria brizantha) under heavy rainfall and high temperatures produced large areas of dry matter within a short period of time. Thus, the cover crops are able to reduce the weed population and the fallow area gets infested quickly and can compete directly with crops in succession.

Assuntos