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Zachrisson B.,Institute Investigacion Agropecuaria Of Panama | Costa V.,Instituto Biologico | Bernal J.,Autonomous University of Chiriqui
Idesia | Year: 2014

The objective of this work was to determine the parasitism rate of Oebalus insularis eggs, in different rice varieties (CONAGRO-2, ESTRELLA-92, IDIAP-5405). The parasitism rate of O. insularis eggs was determinated under controlled conditions of temperature (25±1 °C), relative humidity (85±3%) and photophase (12 hours). The parasitoids Telenomus podisi and Trissolcus basalis were identified. The average parasitismo rate of parasitoids complex was above 90% and the most abundant specie was Te. podisi, with 81, 8% parasitism.

Marin F.,University of Almeria | Dianez F.,University of Almeria | Santos M.,University of Almeria | Carretero F.,University of Almeria | And 2 more authors.
Phytopathologia Mediterranea | Year: 2014

Suppressive effects of different compost teas were evaluated against the phytopathogens P. capsici and P. parasitica, isolated from diseased plants from commercial sweet pepper farms in Almería (Spain), during 2011. Aerated compost tea and non-aerated compost tea were prepared from spent mushroom compost, grape marc compost, crop residues compost and vermicompost. In vitro inhibition of mycelial growth of the two tested pathogens was assessed, and in vivo effects of compost teas on disease severity, caused by P. capsici and P. parasitica were evaluated on pepper plants, in greenhouse experiments. Different morphological parameters were also measured for plants treated with compost teas, to determine growth promotion effects on pepper plants. The compost teas controlled the two tested pathogens in vitro and in vivo. Non-aerated compost teas (NCT) were more beneficial in increasing growth of pepper plants than aerated compost teas. This study demonstrates the clear effect of compost tea on disease suppression and plant growth promotion. These compost extracts may be used as alternatives to inorganic fertilizers/fungicides to enhance plant growth, reduce disease incidence and increase crop yields. © Firenze University Press.

Ruane A.C.,NASA | Ruane A.C.,Columbia University | Cecil L.D.,National Oceanic and Atmospheric Administration | Horton R.M.,NASA | And 7 more authors.
Agricultural and Forest Meteorology | Year: 2013

We present results from a pilot project to characterize and bound multi-disciplinary uncertainties around the assessment of maize (Zea mays) production impacts using the CERES-Maize crop model in a climate-sensitive region with a variety of farming systems (Panama). Segunda coa (autumn) maize yield in Panama currently suffers occasionally from high water stress at the end of the growing season, however under future climate conditions warmer temperatures accelerate crop maturation and elevated CO2 concentrations improve water retention. This combination reduces end-of-season water stresses and eventually leads to small mean yield gains according to median projections, although accelerated maturation reduces yields in seasons with low water stresses. Calibrations of cultivar traits, soil profile, and fertilizer amounts are most important for representing baseline yields, however sensitivity to all management factors are reduced in an assessment of future yield changes (most dramatically for fertilizers), suggesting that yield changes may be more generalizable than absolute yields.Uncertainty around GCMs' projected changes in rainfall gain in importance throughout the century, with yield changes strongly correlated with growing season rainfall totals. Climate changes are expected to be obscured by the large interannual variations in Panamanian climate that will continue to be the dominant influence on seasonal maize yield into the coming decades. The relatively high (A2) and low (B1) emissions scenarios show little difference in their impact on future maize yields until the end of the century. Uncertainties related to the sensitivity of CERES-Maize to carbon dioxide concentrations have a substantial influence on projected changes, and remain a significant obstacle to climate change impacts assessment. Finally, an investigation into the potential of simple statistical yield emulators based upon key climate variables characterizes the important uncertainties behind the selection of climate change metrics and their performance against more complex process-based crop model simulations, revealing a danger in relying only on long-term mean quantities for crop impact assessment. © 2011 .

Garming H.,Tropical Agriculture Research and Higher Education Center | Espinosa J.,Institute Investigacion Agropecuaria Of Panama | Guardia S.,Tropical Agriculture Research and Higher Education Center | Jimenez R.,Instituto Dominicano Of Investigacion Agropecuaria Y Forestal
Acta Horticulturae | Year: 2013

Improved cultivars of banana and plantain for managing biotic and abiotic stress and increasing productivity have been disseminated in many countries. Although some of these hybrids have performed well in many environments, evidence for large-scale adoption and acceptance in national markets is scarce. This study assesses the impact of the banana hybrid FHIA-21 (AAAB) in the Dominican Republic and analyses the factors that facilitated acceptance in national markets and adoption among farmers. Data collection included a household survey with a randomized sample of 182 farmers in the country's most important growing region, the Cibao valley, and interviews with 15 key informants from the public and the private sector involved in research, extension and business related to plantains. Results show that 64% of survey respondents are now growing FHIA-21; of these adopters, 60% also continue cultivating the local cultivars. Results show that respondents who grow both FHIA-21 and the traditional triploids, with similar crop management, get significantly higher yields for FHIA-21 (20-25 t/ha versus 15-18 t/ha for the traditional cultivars). The adoption of FHIA-21 was found to be part of broader technological changes and closely related to the adoption of other modern production practices, such as higher planting densities, irrigation and frequent replanting; leading to particularly large yield differences between FHIA-21-only producers and those who exclusively produce traditional local cultivars. On the fresh markets, FHIA-21 is now widely accepted, although prices are about 30-40% lower, which makes it interesting for poorer consumers. As pointed out by key informants, market acceptance increased quickly after the decision of a large processing company to source FHIA-21 for their green plantain chips production, which was based on an initiative for collaboration between research institutes and the processing industry. The results emphasize the importance of agricultural policy and market conditions to enable and facilitate the large-scale adoption and impacts of new technologies, such as plantain hybrids.

Marin F.,University of Almeria | Santos M.,University of Almeria | Dianez F.,University of Almeria | Carretero F.,University of Almeria | Yau J.A.,Institute Investigacion Agropecuaria Of Panama
World Journal of Microbiology and Biotechnology | Year: 2013

Compost teas (CT) are fermented watery extracts of composted materials that are used to control plant diseases and on crop fertilization. In this work, aerated (ACT) and non-aerated compost teas (NCT) were obtained from four different composts: spent mushroom substrate compost, grape marc compost, greenhouse horticultural crop residues compost, and vermicompost. Physico-chemical and microbiological analysis were carried out to determine their properties. In vitro assays were performed to assess their suppressive effect on the mycelial growth of eight fungal phytopathogens. In vivo trials aimed to assess their effect on gummy stem blight (Didymella bryonae) and powdery mildew (Podosphaera fusca) in melon plants. Results showed that ACT and NCT filtrates inhibited the in vitro growth of all tested pathogens while autoclaved CT did not completely lose their inhibitory effect, and CT sterilized by microfiltration had no effect on the pathogen growth. The severity of powdery mildew was highly reduced by ACT and NCT from all sources, though in gummy stem blight assay only a delay in disease development was observed. In general, all compost teas showed a high level of microbial populations and nutrients. Results suggest that the efficacy of ACT and NCT firstly depend on the microbiota present in them. We consider compost teas from the four tested sources as a viable way to manage plant diseases and crop fertilization, throughout its integration in pest management programs and fertirrigation systems under different dilution rates. © 2013 Springer Science+Business Media Dordrecht.

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