Mostrando entradas con la etiqueta Blueberry diseases. Mostrar todas las entradas
Mostrando entradas con la etiqueta Blueberry diseases. Mostrar todas las entradas

domingo, 30 de abril de 2017

Argentina: Evaluación de la calidad en cosecha de nuevas variedades de ARÁNDANO - Argentina: Quality evaluation of new BLUEBERRY varieties at harvest

http://lv12.com.ar/03-2017/resize_1488450547.jpg

Durante la campaña 2016, un equipo de investigadores argentinos del INTA y otras instituciones, caracterizaron la calidad en cosecha de 8 variedades de arándano (Vaccinium corymbosum) de reciente introducción en la región pedemontana de Tucumán: Farthing, Flicker, Kestrel, Rocío, San Joaquín, Scintilla, Sweet Crisp y Ventura. Para ello se realizaron recolecciones periódicas de frutos maduros. Se analizó calidad de los frutos inmediatamente después de la cosecha mediante los parámetros: apariencia visual/sensorial, diámetro ecuatorial (DE), acidez titulable (AT), sólidos solubles totales (SST), ratio (SST/AT) y susceptibilidad a las pudriciones, medida a través de la incidencia de las mismas (IP). Todas presentaron DE > 12 mm, requeridos para la exportación.

Rocío, Sweet Crisp y Farthing mostraron mayor firmeza y bloom, con mejor apariencia visual/sensorial que el resto. Los mejores índices de calidad (ratios) fueron los de San Joaquín (13,8), Farthing (14,7) y Sweet Crisp (14,9), seguidos por Flicker (18,2) y Ventura (18,7), y por último, Kestrel (19,2), Rocío (20,1) y Scintilla (21), aún con valores aceptables de calidad. Respecto a la IP, las variedades se diferenciaron en 2 grupos: menos tolerantes, con Kestrel, Flicker y Rocío con valores de 68, 61 y 54% respectivamente; más tolerantes, con Sweet Crisp, Farthing, San Joaquín, Scintilla y Ventura, con un 23% en promedio. Este primer estudio brinda información de gran utilidad para el productor para definir el espectro varietal al momento de iniciar o renovar su plantación.
Fuente: Heredia AM, Kirschbaum DS, Funes CF, Pavón E, Ramallo AC.  2017. 4º Congreso Argentino de Fitopatología (AAF), Mendoza, Argentina.

domingo, 12 de junio de 2016

Dry weather speeds BLUEBERRY harvest - El tiempo seco acelera la cosecha de ARÁNDANO

Rabbiteye blueberries make up 80 to 90 percent of the Mississippi’s blueberry crop. Recent dry weather has made harvesting easier than normal. (Photo by MSU Extension Service/File)
The first half of June is usually a busy time for blueberry growers in Mississippi, and this year is no different, as recent dry conditions have expedited the crop’s harvest. A few scattered small-market “U-Picks” can be found in north and central portions of the state, but most of the commercial activity is happening south of Interstate 20, where rain has been in short supply lately. Wayne County boasts the highest blueberry production in the state. 

“The dry weather has accelerated the ripening but also made harvest easier than normal,” said Eric Stafne, an associate Extension and research professor in fruit crops with the Mississippi State University Extension Service and the Mississippi Agricultural and Forestry Experiment Station in Poplarville. “It’s been smooth sailing this year with no major worries about split berries or disease issues.” Amy Phelps, a Pearl River County grower, has grown blueberries commercially in the past but is operating a U-Pick farm this year after a tornado damaged some of her property in February. Despite the setback, she said this year’s crop was one of her best in 16 years.“Whenever the field is stressed by Mother Nature, whatever follows is always big,” Phelps said. “It’s almost like the field is expressing its desire to survive. What we have out there right now is beautiful, and we’ve had ideal picking conditions.”

The Mississippi Agricultural Statistics Service reported 89 percent of the blueberry crop is in good to excellent condition for the week ending May 29. Mandy McCormick grows organic blueberries commercially and opens a U-Pick to the public June 1 each year in Poplarville. She said prices for berries have typically run around $25 to $32 for a 9.5-pound flat, with little change this year. “We can’t pick wet berries because we don’t have a harvester and pick by hand,” she said, “so we welcome all the sunshine we’re getting.” Rabbiteye varieties, which make up 80 to 90 percent of the state’s crop, are generally ready for harvest in late May. The remaining crop mostly consists of Southern highbush varieties, which tend to produce in late April and early May. Rain at the end of this period may have stopped the Southern highbush harvest season prematurely, Stafne said.   

“The rabbiteyes started around May 20, and volumes are increasing at this point,” he said. “We’ll be in the peak of it in mid-June, then we’ll start going into later varieties with lesser volumes in terms of commercial production.” Blueberry production typically continues into July, depending on market demand. Each year, Mississippi has anywhere from 2,000 to 2,500 acres of commercial blueberries. That number was closer to 2,500 acres in recent years, but market conditions are stalling, causing a few growers to switch to other opportunities, Stafne said. “A lot of our production is in the processed market, which means primarily frozen berries. Right now there is a backlog of freezer stock nationwide,” he said. “It’s been difficult to sell that product, so some growers have moved out of the business, and we’re starting to see some slight attrition. But these markets can change quickly. There is always interest from new growers.”

Growers continue to watch for fungi and pests that have compromised crop conditions in the last five years. Exobasidium, a fungal disease found mostly in the Southeast, can be problematic if left untreated. Spotted-wing drosophila fruit flies attack healthy, ripe fruit. Stafne said the pests are relatively new to Mississippi and have been a challenge to control. “We’re just now starting to get into the time period where these fruit flies become a real problem,” he said. “Early varieties miss them for the most part because populations have not yet built up and any that are there are controlled as long as growers are spraying. Timely fungicide sprayings have also limited damage from exobasidium. Growers who have had major problems didn’t treat for the disease.”
Source: Robert Nathan Gregory. Mississippi State University (http://extension.msstate.edu)

sábado, 1 de agosto de 2015

Emerging and re-emerging plant diseases: BLUEBERRY and CITRUS threatened - Enfermedades emergentes y re-emergentes: ARÁNDANO y CITRICOS amenzados

Bacterial Leaf Scorch
Photo source: University of Georgia - CES

Oliver and collaborators (2015) determined that Xylella fastidiosa isolates from both the subspecies multiplex and fastidiosa can cause blueberry leaf scorch under greenhouse conditions. Although currently only X. fastidiosa subsp. multiplex isolates have been recovered from infected blueberry plants in the southeastern United States, X. fastidiosa subsp. fastidiosa occurs commonly on infected grapevine in this region. These authors demonstrated the potential of X. fastidiosa subsp. fastidiosa as a blueberry pathogen, and identified the differences in interactions of blueberry with both both subspecies that could be helpful in the deployment of host resistance as a control strategy.


Photo: http://idtools.org/id/citrus/diseases/images/fs_images/01Leprosis.jpg
Roy and collaborators (2015) provided a fascinating account of citrus leprosis, a disease that was first reported in Florida in the 1860s. Though the disease caused extensive losses, it ceased to be a serious concern in Florida by the 1930s. The disease, however, re-emerged as a major threat to citrus production in South and Central America and is rapidly expanding its geographic range. Citrus leprosis is caused by a complex of viruses involving both cytoplasmic and nuclear viruses. All five viruses that have so far been identified are nonsystemic and cause only local lesions, but differ in their host ranges. These viruses are transmitted by mites in the genus Brevipalpus. In their paper, they describe novel hosts for some of these viruses, new vectors within the genus Brevipalpus, and the replication of both cytoplasmic and nuclear viruses within mite species. This suggests the potential origin of these viruses in mite species, the crucial role of mites in disease transmission, and also the unique role of citrus as a vector of viruses and mites.
Source: http://apsjournals.apsnet.org/doi/full/10.1094/PHYTO-105-7-0001