Preliminary assessment of weed population in vegetable and fruit farms of Taif, Saudi Arabia

Abstract 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.

Resumo Um nível significativo de perdas de rendimento nas fazendas de hortaliças e frutas é atribuído às populações de ervas daninhas da área. Este estudo foi conduzido por dezoito meses durante 2019-2020 para avaliar a presença de várias famílias de ervas daninhas, espécies relacionadas e suas densidades nas fazendas de vegetais (CROP A) e frutas (CROP B) de Taif, Arábia Saudita. Durante o estudo, catorze e dez famílias de plantas daninhas foram observadas nas fazendas de hortaliças e frutas da área estudada, respectivamente. As plantas daninhas da família Poaceae (729) foram significativamente maiores em número, seguidas pelas famílias Asteraceae (414), Chenopodiaceae (338) e Gisekiaceae (153). Nas hortas, duas espécies de plantas daninhas da família Poaceae, incluindo Setaria viridis (437) e Eleusine indica ssp (277), estavam presentes em maior número, seguidas por Chenopodium murale (166) da família Chenopodiaceae. Nas fruticulturas, a espécie de plantas daninhas Cynodon dactylon da família Poaceae representou a maior densidade de plantas daninhas (172) seguida das espécies Gisekia pharnaceoides L. (153) da família Gisekiaceae e Portulaca oleracea (59) pertencentes à família Portulacaceae. As fazendas de hortaliças e frutas da região de Taif enfrentam uma forte pressão de ervas daninhas que afeta as culturas cultivadas. Este estudo apresenta um quadro abrangente da diversidade e densidade de plantas daninhas nas fazendas de hortaliças e frutas da região. Os resultados deste estudo serão benéficos no desenvolvimento de práticas eficazes de manejo de plantas daninhas para uma melhor produção das culturas.

Preliminary assessment of weed population in vegetable and fruit farms of Taif, Saudi Arabia / Avaliação preliminar da população de plantas daninhas em fazendas de hortaliças e frutas de Taif, Arábia Saudita

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.

Um nível significativo de perdas de rendimento nas fazendas de hortaliças e frutas é atribuído às populações de ervas daninhas da área. Este estudo foi conduzido por dezoito meses durante 2019-2020 para avaliar a presença de várias famílias de ervas daninhas, espécies relacionadas e suas densidades nas fazendas de vegetais (CROP A) e frutas (CROP B) de Taif, Arábia Saudita. Durante o estudo, catorze e dez famílias de plantas daninhas foram observadas nas fazendas de hortaliças e frutas da área estudada, respectivamente. As plantas daninhas da família Poaceae (729) foram significativamente maiores em número, seguidas pelas famílias Asteraceae (414), Chenopodiaceae (338) e Gisekiaceae (153). Nas hortas, duas espécies de plantas daninhas da família Poaceae, incluindo Setaria viridis (437) e Eleusine indica ssp (277), estavam presentes em maior número, seguidas por Chenopodium murale (166) da família Chenopodiaceae. Nas fruticulturas, a espécie de plantas daninhas Cynodon dactylon da família Poaceae representou a maior densidade de plantas daninhas (172) seguida das espécies Gisekia pharnaceoides L. (153) da família Gisekiaceae e Portulaca oleracea (59) pertencentes à família Portulacaceae. As fazendas de hortaliças e frutas da região de Taif enfrentam uma forte pressão de ervas daninhas que afeta as culturas cultivadas. Este estudo apresenta um quadro abrangente da diversidade e densidade de plantas daninhas nas fazendas de hortaliças e frutas da região. Os resultados deste estudo serão benéficos no desenvolvimento de práticas eficazes de manejo de plantas daninhas para uma melhor produção das culturas.

Soybean yield loss and economic thresholds due to glyphosate resistant hairy fleabane interference / Perda de rendimento da soja e nível de dano econômico pela interferência de buva resistente ao glifosato

The interference of glyphosate resistant hairy fleabane (Conyza bonariensis) has caused yield losses in soybean crop. Knowledge of the economic threshold is an important aspect for the economic management of resistant weeds. Because of it, the interference of the glyphosate resistant hairy fleabane density on the soybean yield loss was evaluated, as well as to estimate the economic threshold. Two experiments were conducted to verify the effect of different weed densities on the yield of two soybean cultivars (BRS Estância and BMX Turbo). Weed density ranged from 0 to 124 plants m-2. The yield of the BRS Estância decreased by 1.4% to the increase of one single plant, while for the BMX Turbo the loss was 25.9%. Soybean yield and economic threshold were lower for the BMX Turbo cultivar compared to the cultivar BRS Estância, which can be attributed to the genotype, competitive ability, weed development stage and/or environment. Increases in crop yield expectation, soybean price and herbicide efficiency reduce the economic threshold, indicating that the adoption of control measures should be taken when the weed density is low. Due to the high cost of hairy fleabane control, it is only feasible at high densities.(AU)

A interferência de plantas de buva (Conyza bonariensis) resistente ao herbicida glyphosate tem causado perdas de produtividade na cultura da soja. O conhecimento do nível de dano econômico é um importante fator para o manejo econômico de plantas daninhas resistentes na cultura da soja. Para isso, foi avaliada a interferência da densidade de buva resistente ao glyphosate sobre a perda de rendimento da soja, bem como estimado o nível de dano econômico. Dois experimentos foram conduzidos para verificar o efeito de diferentes densidades da planta daninha sobre a produtividade de dois cultivares de soja (BRS Estância e BMX Turbo). As densidades de buva variaram de 0 a 124 plantas m-2. A produtividade do cultivar BRS Estância reduziu 1,4% ao aumento de uma planta, enquanto para o cultivar BMX Turbo a perda foi de 25,9%. A produtividade da soja e o nível de dano econômico foram menores para o cultivar BMX Turbo, em comparação com o cultivar BRS Estância, o que pode ser atribuído ao genótipo, à habilidade competitiva, ao estádio de desenvolvimento da buva e/ou a ambiente. Aumentos na expectativa de produtividade da cultura, no preço da soja e na eficiência dos herbicidas reduzem o nível de dano econômico, indicando que a adoção de medidas de controle deve ser tomada quando a população de buva é baixa. Em função do elevado custo de controle da buva, este somente é viável em altas densidades.(AU)

Evaluation of Low Dose Herbicides in Transplanted Rice (Oryza Sativa L.).

A field experiment was conducted during kharif 2011 at College of Agriculture, Rajendranagar. The experiment consisted of 12 treatments laid out in randomized block design with three replications consisting of two pre-emergence herbicides integrated with post emergence herbicides and one hand weeding at 40DAT and two post emergence herbicide, hand weeding twice at 20 and 40 days after transplanting, compared with weed free and unweeded check. The predominant weed flora observed in the experimental field were Echinochloa crusgalli, Panicum repens, Cynodon dactylon, Cyperus rotundus, Cyperus difformis, Eclipta alba and Ammania baccifera. The results revealed that pre-emergence application of Bensulfuron methyl 0.6% + Pretilachlor 6% @ 10 kg granules ha- 1+ Hand weeding at 40 DAT (5455 kg ha-1 and 6345 kg ha-1) and Bensulfuron-methyl 0.6% + Pretilachlor 6% @ 10 kg granules ha-1 + Bispyribac sodium @ 25 g a.i ha-1 recorded significantly higher grain and straw yield (5365 and 6265kg ha-1, respectively) which remained at par with two hand weedings at 20 and 40 DAT (5580 and 6464 kg ha- 1). In terms of economics, highest net returns (Rs. 33,189 ha-1) and B:C ratio (1.40) were also high with the preemergence application of Bensulfuron-methyl 0.6%+ Pretilachlor 6% @ 10 kg granules ha-1+ Bispyribac sodium @ 25 g a.i. ha-1 at 20DAT (1.40) compared to that of two hand weedingds (Rs. 31,952 ha-1) and benefit cost ratio (1.17) .

Plant Spacing and Weed Management Techniques Influence Weed Competitiveness of Drum Seeded Rice (Oryza sativa L.).

Direct wet seeded-rice sown through drum seeder, a potential wise rice production system in the present-day scenario, is subject to severe weed infestation and, therefore, development of a sustainable weed management strategy is crucial for its wide spread adoption. The present study was conducted in kharif 2012 at department of agronomy division with NLR-33358 (SOMASILA) using six planting densities under five weed management conditions. The plant spacing tried were: 20cm x 7cm, 20 cm x 10.5 cm, 20 cm x 14 cm, 20 cm x 17.5 cm and 20 cm x 24.5cm and 20 cm x15cm. with a plant density of 71, 47, 35, 28, 20 and 33 hills m-2, respectively and five weed management practices viz., weedy check (W1), hand weeding at 20 and 40 DAS (W2), cono weeding at 20 and 40 with modified cono weeder (W3), pre-emergence application of anilofos @ 0.375 kg a.i ha-1 followed by post-emergence application of 2, 4 D sodium salt @ 1.0 kg a.i ha-1 20-25 DAS (W4), pre-emergence application of pendimethalin @1.0 kg a.i ha-1 followed by post-emergence application of bispyribac sodium @ 20 g a.i ha-1 30 DAS ( W5). . The experiment was laid out in strip- plot design with three replications assigning weed management techniques in vertical factor and plant spacing in horizontal factor. Direct wet seeded rice field was infested with 12 and 22 weed species, kharif -2012 season having Echinochloa colona, Leptochloa chinensis, Digitaria aescendens, Cyperus iriaand Eleusine indicaas the predominant weeds. Rice spacing exerted significant influence on both weed pressure and yield performance of crop. With the increase in plant spacing weed dry matter decreased but rice yield increased. In this season, among different plant densities, the highest density of 71 hills m-2(D1) resulted in minimum weed density, weed drymatter, and more number of tillers m-2 and maximum drymatter production at all stages of plant growth. closest spacing resulted in maximum weed suppression, but among various rice plant densities, a medium level population of 47 hills m-2 (D2) significantly increased the paddy yield over all other treatments except D1 treatments with a plant density of 71 hills m-2 .The highest grain yield of 3476 kg ha-1 was observed with a plant density of 47 hills m-2 and it was significantly superior to 71, 35, 28, 20 hills m-2drum seeded and 33 hills m-2 transplant paddies. which ultimately produced the highest rice yield. Weed inflicted relative yield loss was also minimized by the closest spacing. Present findings imply rice spacing mostly determines rice-weed competition, and can play a decisive role to minimize weed pressure. Therefore, closer spacing could be considered as a vital tool in the integrated weed management program for direct wet-seeded rice sown through drum seeder.

Effects of Inorganic Mulches on Achillea millefolium L. Sesquiterpene Lactones.

Aims: Sesquiterpene lactones are one of the most important groups of bioactive substances in Achillea millefolium, a perennial herb cultivated because of its medicinal interest. We sought to determine if the use of inorganic mulches for weed control in A. millefolium crops could lead to differences in their sesquiterpene lactones (SLs) content. Study Design: A field experiment using a randomized complete block design with three replications was conducted to determine the effect of black polypropylene, black polyethylene of 100 µm and black polyethylene of 175 µm on A. millefolium SLs content. Place and Duration of Study: Department of Crop Production, University of Santiago de Compostela, between September 2004 and August 2005. Methodology: LC/MS analysis of A. millefolium flower heads grown over the three different inorganic mulches and in control plots was carried out in order to determine SLs. Results: Chromatographic analysis of A. millefolium flower heads grown over polypropylene and in control plots revealed the highest diversity of SLs, whereas those developed over black polyethylene showed the least. Polypropylene mulches were shown to be the most efficient with a 2-3 fold increase of total SLs (P < 0.001). The effects of inorganic mulches on individual SLs were of limited relevance. However, the use of black polyethylene (100 µm) resulted in an increase of 8-desacetylmatricarin (P = 0.005), a SL of biological and pharmacological interest. In contrast, concentrations of three unidentified SLs decreased in yarrow plants grown over black polyethylene. Conclusion: Weed density did not show as a major factor influencing the total amount of SLs but growth parameters such as yarrow dry matter were inversely related.