Percorrer por autor "Guerrero, Carlos"
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- 5th International European Turfgrass Society Conference: Crop Science Special IssuePublication . Guerrero, Carlos
- Biodetection of turfgrass fungal diseases using sniffer dogsPublication . Serrão, M.; Coelho, Luísa; Dionísio, Lídia; Guerrero, Carlos; Duarte, AmilcarThe results in this work evaluated the sensitivity and specificity of the olfactory capacity of the intervening dog in the fungus biodetection. On 100 attempts, a sensitivity and a specificity of 100% (Table 1) were obtained for the biodetection of the fungus Sclerotium rolfsii when the 4-year-old English Springer Spaniel female dog was faced to a straight line of 5 equally distanced Falcons. The post-inoculation time of the samples, used in the sessions, varied between 24 and 72H, however there was no difference in the detection response by the female dog Julieta. This is also a noteworthy additional fact, given the potential for prevention that can represent the detection of a fungus with such a short post-inoculation time. Further work is being established to assess the olfactory ability to detect the presence of the fungus in inoculated turfgrass samples and finally to detect it in the field.
- Biological control of turfgrass diseases with organic composts enriched with Trichoderma atroviridePublication . Coelho, Luísa; Reis, Mário; Guerrero, Carlos; Dionísio, LídiaThe increasing demand of natural products for the control of plant diseases has led to the search for biological control agents, namely fungi, often isolated from composts of organic residues. By composting two different mixes of agro-industrial residues, P1 and P2 composts were obtained, from where a known antagonist, Trichoderma atroviride, was isolated. Later, a second composting process was performed and when the composting mix reached room temperature, the previously isolated T. atroviride was inoculated in both composts to enrich its population (E) and named as P1E and P2E. The suppressive capacity of these two composts against Sclerotium rolfsii, Clarireedia spp. and Rhizoctonia solani was tested two weeks after T. atroviride inoculation, in 100 mL pots with turfgrass seeded with Agrostis stolonifera. The tested treatments were: composts P1 and P2 without any treatment; thermally treated P1 and P2 (P1t, P2t); P1 and P2 enriched without and with previous thermic treatment (P1E, P2E, P1tE, P2tE), and a commercial peat-based substrate, natural (P) and thermally treated (Pt), enriched (PE) and enriched after thermal treatment (PtE). Enriched composts achieved the highest disease control. P1E was more effective in controlling Clarireedia spp.; pots with infected plants grown on P1E, showed 53.5% less affected area compared to P1t. P2E was more effective against R. solani; results showed 69.3% less affected area compared to P2t and both were effective in S. rolfsii control, with a reduction of 38.5% in P1E and 43.5% in P2E. The larger population of Trichoderma spp. observed in the enriched substrates associated to the greater enzyme activity, namely and N-acetyl-β-glucosaminidase, standing out in P2E, will have contributed strongly to the biocontrol of the studied diseases. An increase in some macro and micronutrients was observed in the enriched heat-treated substrates.
- Controlo de Sclerotinia homoeocarpa em relva com compostos orgânicosPublication . Coelho, Luísa; Dionísio, Lídia; Guerrero, Carlos; Reis, MárioOs relvados são suscetíveis a doenças causadas por fungos, sendo Sclerotinia homoeocarpa um dos que causa maiores prejuízos em muitos países. A compostagem permite a valorização e tratamento de resíduos orgânicos, originando compostos com aplicações agrícolas, nomeadamente para controlo de doenças causadas por patogénicos do solo. Produziram-se dois compostos, designados P1 e P2, por compostagem de resíduos agroindustriais, em pilhas com arejamento por reviramento. Desde o final da fase termofílica até ao final dos processos de compostagem recolheram-se amostras onde se isolaram e identificaram fungos presentes em ambos os compostos. Dos isolados, 26 apresentaram potencial antagonista, sendo 12 provenientes de P1 e 14 de P2. Realizaram-se ensaios in vitro, pelo método de confrontação direta, para avaliar a capacidade antagonista destes fungos para S. homoeocarpa. Doze dos isolados, dos géneros Trichoderma, Fusarium e Bionectria, impediram o crescimento de S. homoeocarpa, com taxas de inibição entre 52 e 68%. Os compostos obtidos foram também testados, in vivo, em relva (Agrostis stolonifera L.) cultivada em vaso. No cultivo em vaso, usando os compostos como substratos, verificou-se redução da área de relva afetada pela doença, principalmente em P2. Os compostos testados controlaram S. homoeocarpa tanto in vitro como em vaso destacando-se o composto P2.
- Effects of a severe recovery pruning in the productivity and fruit quality of two late orange cultivarsPublication . Matias, Pedro; Duarte, Beatriz; Mendonça, Angélica; Oliveira, Silvino; Barrote, Isabel; Guerrero, Carlos; Duarte, AmilcarCurrently, citrus production plays a major role in worldwide agriculture, especially in the Mediterranean. However, the typical irregular branch development and the formation of large canopies and dense exterior foliage can be significant limitations to light entry and air circulation through the canopy. Consequently, dead branches appear in the inner canopy, which becomes unproductive; flowering and vegetative growth occur only on the outer canopy, and the fruits formed usually are of lower quality. Furthermore, dead branches can be an inoculum for some pathogenic microorganisms, chemical treatments become less efficient since reaching the inner canopy branches becomes more difficult, and fruit harvest becomes harder and more expensive. Pruning is a cultural practice that allows canopy management and the control of the problems mentioned above. However, many citrus growers avoid or postpone pruning, or prune insufficiently due to pruning’s high costs and, sometimes, direct production losses. To assess the effects of pruning, two experiments were performed on large canopy trees: one in ‘Valencia Late’ and the other in ‘Dom João’. In both experiments, some trees were left unpruned (control) and others were severely pruned in November 2019 (recovery pruning). The pruning was made by removing at least 30% of the canopy, with the complete removal of a few large branches. Pruning allowed a significant increase in light availability inside the canopy. In the 2020 harvest, there were no differences in fruit size between treatments. The production decreased in the pruned trees in the ‘Dom João’ experiment, as expected, and was similar in the ‘Valencia Late’ experiment. In the 2021 harvest, in both experiments, the pruned trees had a smaller canopy, and the production was similar in both treatments. However, the fruits from pruned trees were bigger in the ‘Dom João’ experiment and several quality parameters were better in the ‘Valencia Late’ experiment.
- Effects of compost application on nematode populations and the yield of a carrot cropPublication . Coelho, Luísa; Reis, Mário; Bueno-Pallero, Francisco; Guerrero, Carlos; Gonçalves, M. A.Composts may be used either in soilless cultivation or applied to soil, increasing its organic matter content and improving the physical, chemical and biological properties. This study evaluated the effects of compost application to the soil cropped with carrot on nematodes diversity, biocontrol of phytopathogenic nematodes and crop yield. A commercial compost (Organical®, TerraFértil, Portugal) was applied to a sandy soil, at the rate of 0, 12.5, 25, 50 and 100 t ha-1 and incorporated to a 15 cm depth. A carrot crop (Daucus carota L.) was sown with a density of 62.5 plants m-2. At the end of the growing period, when the longer roots had reached about 15 cm, plant growth and yield were quantified. Compost increased carrot yield. Following harvest, soil samples were collected near the roots (root zone) and randomly at three soil depths: 0 to 15 cm, at 30 cm and at 50 cm. Nematodes species were identified and quantified in these four zones, and the damages observed were ranked. Compost influenced nematode populations. Near the roots beneficial nematode populations increased with the compost rate application. Phytopathogenic nematodes were present mainly in the treatments with less compost. Furthermore, nematode genera were distributed according to soil depth. Bacteriophage/saprophyte nematodes were found mainly at 50 cm depth, at the surface and in the root zone. Plant parasitic nematodes were located near the surface (0-15 cm) and at 50 cm depth. Predator nematodes prevailed near the surface, in the root zone and at 50 cm depth. The lower populations of nematodes were found at 30 cm depth. This work showed that the dynamics of nematode populations in the soil is affected by soil depth and compost dose, suggesting that compost can reduce the population of phytopathogenic nematodes and increase bacteriophage/saprophyte and predator nematode populations.
- Essential oils of Portuguese Thymus mastichina (L.) L. subsp mastichina grown on different substrates and harvested on different datesPublication . Miguel, Maria Graça; Guerrero, Carlos; Rodrigues, H.; Brito, J.; Duarte, F.; Venancio, F.; Tavares, R.The effects of harvesting date and different substrates on the yield and chemical composition of the essential oils of Portuguese Thymus mastichina (L.) L. subsp. mastichina were compared with samples grown in pots. The best oil yields were obtained in June (3.2, 3.6 and 4.9% in the local sandy soil, in non-fertilized peat, and in fertilized peat, respectively). The essential oils were dominated by 1,8-cineole, the highest concentration of which was detected in June (58.6%) in samples kept in non-fertilized peat, and the lowest values were from plants growing in fertilized peat during April and June (45.1%). The remaining samples always reached the highest percentages in October (around 54% in both oil samples), although the concentration profile over time was similar in every sample. Concerning the monoterpene hydrocarbons, a-pinene, camphene, sabinene and P-pinene were the most significant components. While the amounts of alpha-pinene tended to decrease from April to June, for P-pinene such tendency was observed from October to January, independently of the growing material used. Amounts of camphene, being similar to those of alpha-pinene, decreased successively from October to April. Elemol and intermedeol were the most representative sesquiterpene components, although the concentrations never exceeded 2.2% and 1.3%, respectively. The results obtained in this work suggest that the harvesting dates of Portuguese T mastichina influence oil yields and their chemical compositions much more than the different growing media used, although a higher oil yield was obtained with the fertilized growing material.
- Essential oils of Rosmarinus officinalis L., effect of harvesting dates, growing media and fertilizersPublication . Miguel, Maria Graça; Guerrero, Carlos; Rodrigues, H.; Brito, J.; Duarte, F.; Venancio, F.; Tavares, R.The effects of the harvesting date, growing media and fertilizers on the yield and chemical composition of the essential oils of Rosmarinus officinalis L. maintained in pots were evaluated. The highest oil yield was always obtained in June, being superior or equal to 1 %. Myrcene was the major component present in the essential oils with concentrations always exceeding 20 %, independent on the factors studied. 1,8-Cineole (8.0-12.2 %), a-pinene (8.8-16.5 %) and, in some instances, camphor (4.4-14.1 %) could be also detected in considerable amounts, however never exceeding the myrcene percentages. The amounts of camphor (4.4-8.5 %) were always inferior to the 1,8-cineole levels (8.8-11.8 %) in the local sandy soil regardless the fertilization used. Generally, the lowest levels of myrcene and verbenone were observed during January and April while the highest amounts of 1,8-cineole was observed in April or June. The yield and the chemical composition of the rosemary oils seemed to be more sensitive to the temperature, photoperiod and collection period than to the growing media material or to the fertilization used.
- First report of curvularia trifolii causing curvularia blight in agrostis stolonifera in South of PortugalPublication . Coelho, Luísa; Borrero, C.; Bueno-Pallero, Francisco Angel; Guerrero, Carlos; Fonseca, Filomena; Reis, Mário; Avilés, M.; Dionísio, LídiaAlgarve region (Portugal) has nearly 40 golf courses with a significant economic impact. Summer surveys on 10 golf courses detected an unknown disease on one course in 2009 and on another course in 2012 and 2013 at 29 to 30°C daily average. The second course had symptoms on about 25% of the turf of two putting greens. Diseased bentgrass (Agrostis stolonifera L.) had a green dappled pattern with irregular patches of turfgrass on yellowed leaves. Prior to decaying, affected leaves turned brown and then gray. Crown and leaf sheath infections resulted in dark brown dry rot. No lesions were observed on the roots. Leaves were surface disinfected with 5% commercial bleach (0.225% sodium hypochlorite) and cultured on potato dextrose agar (PDA). Ten fungal colonies grew from the leaf tissue, and brown mycelia, conidiophores, and conidia were observed under a microscope. Conidia were ventricose pyriform, mostly abruptly curved, 20 to 36 µm (30 µm, SD = 4) × 7 to 12 µm (10.5 µm, SD = 1.3) (n = 50), predominantly three-septate, with a prominent hilum and enlarged and darkened central cells. Colonies grown on PDA were black-brown with a black reverse side. Conidia differed in size, 15.4 to 24.6 µm (19.99 µm, SD = 3.00) × 6 to 11 μm (8.68 µm, SD = 1.54) (n = 50) and morphology (cylindrical or slightly curved). These characteristics were consistent with Curvularia trifolii (Kauffm.) Boedijn. (Ellis 1971; Falloon 1976; Khadka 2016). Species identification of the representative isolate A2 1.12 was confirmed by analysis of nucleotide sequences of the ITS1-5.8S-ITS2 region using primers ITS1 and ITS4 (White et al. 1990) and GPDH gene region with primer set gpd (Koike et al. 2013). BLAST searches of GenBank showed a high similarity of the isolate ITS sequence (MG029439) to the reference sequence JN712458 of C. trifolii (99% identity) and GPDH sequence (MK570108) with LT715803.1 (97.88% identity). The maximum likelihood phylogenetic tree showed that our isolate clustered with C. trifolii. The pathogenicity assay of this isolate was conducted in greenhouse on A. stolonifera ‘Penncross’. The isolate was grown on PDA (25°C, 10 days). Five pots (100 ml) were filled with a sand and peat mix (9:1 v/v) with 0.06 g of seeds per pot, covered with a fine sand layer. Turfgrass was cut once a week beginning 2 weeks after seeding and was fertigated with 0.5 g/liter of Peter’s foliar feed (27 + 15 + 12; N + P2O5 + K2O; and micronutrients; Scotts, Heerlen, The Netherlands). To obtain a conidial suspension for inoculation, cultured plates were scraped with a sterilized spreader and water. The suspension was filtered through a sterile gauze. Conidia were counted under a microscope (400×) with a hemocytometer. The suspension was adjusted to 8 × 103 conidia/ml, and 10 ml was sprayed per pot. Pots maintained humidity for 2 days under microtunnels. The first disease symptoms appeared 3 days after inoculation. Bentgrass from the five pots developed Curvularia blight and rotted crown symptoms. Control plants (five pots treated with water) did not display symptoms. This trial was repeated once. On PDA, C. trifolii was reisolated from leaf lesions and morphologically identified, confirming Koch’s postulates. Ellis (1971) referred to the presence of C. trifolii in Portugal, but no region, symptom description, or grass species was detailed. Sivanesan (1987) reported C. trifolii in Portugal only on Lolium multiflorum. Therefore, this is the first report of C. trifolii in Algarve, affecting A. stolonifera. This disease can increase maintenance costs in greens in this area.
- Hybrid neural network based models for evapotranspiration prediction over limited weather parametersPublication . Vaz, Pedro J.; Schutz, G.; Guerrero, Carlos; Cardoso, PedroEvapotranspiration can be used to estimate the amount of water required by agriculture projects and green spaces, playing a key role in water management policies that combat the hydrological drought, which assumes a structural character in many countries. In this context, this work presents a study on reference evapotranspiration (ETo) estimation models, having as input a limited set of meteorological parameters, namely: temperature, humidity, and wind. Since solar radiation (SR) is an important parameter in the determination of ETo, SR estimation models are also developed. These ETo and SR estimation models compare the use of Artificial Neural Networks (ANN), Long Short Term Memory (LSTM), Gated Recurrent Unit (GRU), Recurrent Neural Network (RNN), and hybrid neural network models such as LSTM-ANN, RNN-ANN, and GRU-ANN. Two main approaches were taken for ET(o )estimation: (i) directly use those algorithms to estimate ETo, and (ii) estimate solar radiation first and then use that estimation together with other meteorological parameters in a method that predicts ETo. For the latter case, two variants were implemented: the use of the estimated solar radiation as (ii.1) a feature of the neural network regressors, and (ii.2) the use of the Penman-Monteith method (a.k.a. FAO-56PM method, adopted by the United Nations Food and Agriculture Organization) to compute ETo, which has solar radiation as one of the input parameters. Using experimental data collected from a weather station (WS) located in Vale do Lobo (Portugal), the later approach achieved the best result with a coefficient of determination (R-2) of 0.977. The developed model was then applied to data from eleven stations located in Colorado (USA), with very distinct climatic conditions, showing similar results to the ones for which the models were initially designed ((R2) > 0.95), proving a good generalization. As a final notice, the reduced-set features were carefully selected so that they are compatible with free online weather forecast services.
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