633 research outputs found

    Effects of Sudangrass Cover Crop and Soil Solarization on Weed and Pathogen Management in Organic Strawberry Production

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    Field and lab experiments were conducted to determine the efficacy of sudangrass (Sorghum X drumondii (Nees ex Steud.) Millsp. & Chase) cover crop management techniques and soil solarization on important agricultural weeds and pathogens in organic strawberry production in Central California. Lab experiments assessed the time needed to kill weed seeds at temperatures typically achieved during soil solarization (40°C, 45°C, 50°C, 55°C, and 60°C) in California. Seeds tested included little mallow, redstem filaree, bristly oxtongue, annual sowthistle, common purslane, nettleleaf goosefoot, and redroot pigweed. Efficacy of simulated solarization temperatures differed between different species. Cool-season annuals annual sowthistle and bristly oxtongue were more susceptible to heat treatments than warm-season annuals common purslane, redroot pigweed and nettleleaf goosefoot. Hard seeded weed species little mallow and redstem filaree were the least susceptible to heat treatments. Annual sowthistle, bristly oxtongue and nettleleaf goosefoot were affected at all temperatures. Redroot pigweed and little mallow were not affected by temperatures below 40°C. Common purslane was not affected by temperature below 45°C and redstem filaree was not affect by any temperatures tested. Hours of exposure and percent mortality of weed seeds were used to create thermal death models for weed seeds. Field experiments were conducted at the Cal Poly Organic Farm in San Luis Obispo, CA testing the effects of soil solarization and sudangrass residues on weeds, Verticillium dahliae populations, plant health, and yields in organic strawberry production. Using a split plot design, sudangrass was grown, mowed and then developed into two treatments: surface mulch or incorporated into the soil. The sudangrass treatments and a control were tested with and without soil solarization (n=4). Maximum soil temperatures in solarized treatments were 53°C at a soil depth of 5 cm and 42°C at a soil depth of 15 cm. Solarization reduced weed biomass between 49.8 and 95.2% during the first 3.5 months after tarp removal (p=0.03), reduced Verticillium dahliae populations by 80.7% (p=0.01), reduced plant mortality by 54.9% (pV. dahliae populations (p=0.33) or yields (p=0.25). However, mulched treatments reduced weed biomass between 45.0 and 61.3% (p=0.03) compared to other sudangrass treatments. Results indicate solarization can be used in central coast organic strawberry production to reduce hand-weeding, disease incidence, and increase yields

    Soil Solarization and Calcium Cyanamide Affect Plant Vigor, Yield, Nutritional Traits, and Nutraceutical Compounds of Strawberry Grown in a Protected Cultivation System

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    Soil solarization is a hydrothermal procedure of disinfesting soil of soilborne diseases and pests. Solarization can be combined with many other chemical or non-chemical alternatives to afford integrated pest and diseases management or improve plant yield. Calcium cyanamide (CaCN2) is a fertilizer used in agriculture sector and is also effective in suppressing soilborne pathogens. The present study assessed the influences of different pre-plant CaCN2 dosages on strawberry grown on solarized or non-solarized soil. Soil solarization and 500 kg ha−1 CaCN2 significantly increased early marketable yield by 105.3%, total marketable yield by 53.0% and firmness by 3.0%, respectively compared with the control (no solarization × 0 kg ha−1 of CaCN2). Exposing solarized plots to CaCN2 at 1000 kg ha−1 significantly increased fruit ascorbic acid content by 77.5% and phenolic content by 13.3% compared with fruits from control plants. Overall, plants grown on solarized soil performed better than those cultivated on no-solarized plots. Plants grown on soil treated with a dosage of 500 or 1000 kg ha−1 CaCN2 increased plant height, number of shoots plant−1, number of leaves plant−1, root collar diameter, plant visual quality, anthocyanins, and antioxidant capacity compared to control plants. Fruits from plants grown on soil exposed to CaCN2 with a dosage of 500 and 1000 kg ha−1 showed a lower N fruit content (5.4 and 19.5%, respectively) than control plants (non-treated control)

    Effect of Biofumigation on Typical Weeds of Strawberry Fields

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    This research was conducted to evaluate the effect of biofumigation using fresh organic matter on typical weeds present in strawberry fields of southern Spain. Field experiments consisted of biofumigation (BF) treatment over 45 days, at two locations, with hen droppings or horse manure at a dose of 3 kg m-2, alone or in combination with solarization (BF+S) in an experimental randomized block design. Results showed good control of the main weed species, Poa annua, Portulaca oleracea and Lolium rigidum, with comparative populations of the three species under BF/BF+S of 42/4/8, 18/9/12, and 15/0/1 plants m-2 respectively. In addition, 20 seeds each of several weeds were sown inside cloth bags and were submitted to the treatment. The efficiency of biofumigation combined with solarization in the control of P. oleracea, Cynodon dactilon and Echinochloa crus-galli was 77/0, 50/15, and 30/2, as a percentage of germination of control/BF+S. Laboratory experiments consisted of simulating field conditions using a mix of soil, water and different fresh organic matter in a plastic bag, into which different seeds were sown and kept under controlled conditions over 30 days at 27ºC. Fresh organic matter used was whole strawberry plants, horse manure, hen droppings, and combinations of these. Best results were obtained with hen droppings, which showed effective control of Malva parviflora, Medicago sp., E. crus-galli, Amaranthus retroflesuxus, Chenopodium album and P. oleracea, while strawberry residues and horse manure were not useful as herbicides, sometimes even less so than the solarization treatment. Biofumigation with fresh hen droppings and solarization showed promising results in preliminary experiments

    An Efficient Irrigation System for Plasticulture of Strawberry in Bangladesh

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    Plasticulture technique is a commonly used technique for advanced strawberry production. Due to high cost and tough maintenance, this technique is not practiced commercially in Bangladesh. We have found that, if the irrigation system can be switched to a cheaper one with high efficiency, then the cost can be minimized. We applied Micro-drip mediated irrigation system to minimize the cost. Our proposed modification of plasticulture using micro-drip irrigation system was outstanding in all our concerned horticultural parameters like height of the plants, number of leaves, north-south spreading, and east-west spreading of the plants. Paired Samples analysis between conventional and plasticulture procedure, test of significance for the pairs of mean, analysis of variance and LSD test at 5% level of significance were done for statistical analysis to conclude the  result. The statistical analysis has also shown that the plasticulture method proposed by us was highly significant over the conventional technique and practical for the rural farmer of Bangladesh. It reduces the production costs, improves fruit quality and yield, and reduces the need for chemical pesticides. Keywords: Micro drip irrigation, Soil solarization, Mulching, and Fruit Qualit

    An Integrated Approach for Controlling Verticillium Wilt of Strawberry

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    Strawberry (Fragaria x ananassa, Duch.) is an important crop in California, with more than 35,000 acres planted in 2018 resulting in a farm gate value of $3.1 billion. In 2020, California strawberry production accounted for more than 85% of national strawberry production and faces serious threats to production due to various soil-borne diseases. One such disease, Verticillium wilt, is caused by the fungal pathogen Verticillium dahliae and is commonly found in temperate zones around the world where strawberries are grown. Due to the phase-out of efficacious fumigants like methyl bromide, alternative disease management methods have become necessary to alleviate threats to production. Alternative fumigation practices such as crop termination have recently been investigated, and the integration of crop termination with bed fumigation and host resistance can play an integral role in control of Verticillium wilt. A field trial was established at California Polytechnic State University, San Luis Obispo to examine the efficacy of integrative management solutions for control of Verticillium wilt of strawberry in a naturally infested field. The efficacy of sequential fumigation applications of crop termination and bed fumigation was examined. Further, the integration of a resistant cultivar was also implemented in hopes of further decreasing plant mortality and increasing yield. Different fumigant products such as metam potassium, metam sodium, and chloropicrin were used to assess their performance in different fumigation applications. Metam potassium and metam sodium were used for crop termination. When used for crop termination, both products delivered significant reduction in soil inoculum density and adequate crop injury. Metam potassium, metam sodium, and chloropicrin were used for bed fumigation. All products reduced soil inoculum density. Lower plant mortality and higher yield resulted from sequential applications of crop termination and bed fumigation, with average plant mortality for non-treated control plots and sequentially fumigated plots being 67.2% and 24.1%, respectively. There were no significant increases in yield for plots bed fumigated and sequentially crop terminated and bed fumigated, but significant increases in yield for all plots treated versus the non-treated plots were found. The integration of a moderately resistant cultivar Valiant after the fumigation series showed lower mortality and higher yield versus a susceptible cultivar Seascape. A two-year study was also conducted in order to evaluate host resistance to Verticillium wilt in 74 cultivars and elite breeding lines from five strawberry breeding programs. Genotypes were established in a field naturally infested with V. dahliae on the campus farm at California Polytechnic State University, San Luis Obispo. All five breeding programs had a wide range of susceptibility to Verticillium wilt, ranging from 1.5% to 100% mortality for both years of the trial. Twenty-three cultivars and elite breeding lines were common to both years of the trial; of these, five cultivars showed vastly different results between the two years. For example, ‘Monterey’ showed 78.8% mortality in 2021 and 11.5% mortality in 2022. This demonstrates the importance of evaluating host resistance over multiple years under different environmental conditions and field locations

    Biocontrol of root and crown rot in tomatoes under greenhouse conditions using Trichoderma harzianum and Paenibacillus lentimorbus. Additional effect of solarization

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    Indexación: ScieloTrichoderma harzianum 650 (Th650) and Paenebacillus lentimorbus 629 (Pl629) selected earlier for their ability to control Rhizoctonia solani, Fusarium solani and F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide (MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex F. oxysporum f. sp. lycopersici - Pyrenochaeta lycopersici - Rhizoctonia solani. Evaluations were also performed independently for root damage caused by P. lycopersici, and also for R. solani in the summer assay. MeBr decreased tomato root damage caused by the complex from 88.7% to 21.2% and from 78.4% to 35.7% in the summer and in the winter assay, respectively. None of the bio-controllers could replace MeBr in the winter assay, but Th650 and Pl629 reduced root damage caused by this complex in the summer assay. Treatments with bio-controllers were improved by their combination with solarization in this season. Independent evaluations showed that the positive control of Th650 towards R. solani and the lack of effect on P. lycopersici correlates well with the endochitinase pattern expressed by Th650 in response to these phytopathogens. Root damage caused by R. solani can be controlled at a similar level as it does MeBr in summer assays, thus representing an alternative to the use of this chemical fungicide for the control of this phytopathogen.Financial support: Fondecyt 1990785

    Effects of olive processing waste, chicken manure and Dazomet on weeds with or without soil solarisation

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    Three non-chemical weed control alternatives (chicken manure (10 t ha-1), olive processing waste (OPW) (30 t ha-1), and solarisation (6-7 weeks at > 40.9 - 47.1oC at a 15 cm soil) were applied to greenhouse grown tomatoes alone and in combination and were compared with a soil fumigant (dazomet) for the ability to control weeds. Both dazomet (485 kg a.i. ha-1) and solarisation provided excellent control of common purslane, slender amaranth and bristly foxtail. Excellent weed control was also achieved witha half dose of dazomet (242.5 kg a.i. ha-1) plus 21 days of solarisation. OPW provided moderate control of these weeds, but chicken manure did not. OPW and chicken manure applied with solarisation provided 100% control of common purslane, slender amaranth and bristly foxtail, but did notsignificantly improve control compared to solarisation alone. OPW plus a short-duration of solarisation may provide weed control that is comparable to dazomet in greenhouse grown tomatoes

    Efecto de la solarización en patógenos fungosos que afectan al Eucalipto (Eucalyptus urograndis) en condiciones de vivero

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    Eucalyptus is the most cultivated hardwood tree genus in the world, valued for its yield and the quality of the wood for multiple uses; however, pathogens such as Rhizoctonia and Cylindrocladium threaten the establishment of the crop, since they cause seedling death in the nursery. Among the management strategies, disinfection of the substrate is recommended, and solarization is an effective alternative for the management of soil fungi. The objective of this research was to verify the survival of Rhizoctonia spp. and Cylindrocladium spp. in a nursery substrate subjected to solarization. The substrate was inoculated with two fungal isolates (Rhizoctonia spp. and Cylindrocladium spp.) at three depths (5, 10 and 15 cm), and treated with three solarization methods (free exposure, solarization and solarization + dazomet). Survival of pathogens in the substrate was measured at 15, 30 and 55 days after inoculation, and temperature at 10 and 15 cm depth. Solarization alone had no effect on pathogen mortality. Solarization plus dazomet decreased fungal presence by 100% at all depths and evaluation times. The solarized treatments increased substrate temperature by 49 and 40°C at 10 and 15 cm depth, respectively, with an increase of 10 and 7°C over the control. Therefore, solarization plus dazomet application can be used as a method of substrate disinfection in Eucalyptus nurseries.Eucalyptus es el género de árboles de madera dura más cultivado mundialmente, valorado por su rendimiento y la calidad de la madera para múltiples usos; sin embargo, los patógenos como Rhizoctonia y Cylindrocladium ponen en riesgo el establecimiento del cultivo, debido a que causan muerte de plántulas en vivero. Dentro de las estrategias de manejo se recomienda la desinfección del sustrato, siendo la solarización una alternativa eficaz para el manejo de hongos del suelo. El objetivo de esta investigación fue verificar la sobrevivencia de Rhizoctonia spp. y Cylindrocladium spp. en un sustrato de vivero sometido a solarización. El sustrato fue inoculado con dos aislamientos fúngicos (Rhizoctonia spp. y Cylindrocladium spp.) a tres profundidades (5, 10 y 15 cm), y tratados con tres métodos de solarización (Libre exposición, solarización y solarización + dazomet). Se midió la sobrevivencia de los patógenos en el sustrato a los 15, 30 y 55 días después de la inoculación, y la temperatura a 10 y 15 cm de profundidad. La solarización por sí sola no tuvo efecto sobre la mortalidad de los patógenos. La solarización más dazomet disminuyó la presencia de los hongos en un 100% en todos las profundidades y tiempos de evaluación. Los tratamientos solarizados aumentaron la temperatura del sustrato en 49 y 40°C a 10 y 15 cm de profundidad, respectivamente, con un incremento de 10 y 7°C respecto al testigo. Por tanto, la solarización más la aplicación de dazomet puede emplearse como método de desinfección de sustratos en vivero de Eucalipto
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