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Read more about the article Development of alternate fertilization programs to mitigate nutrient problems found in long-term organic production systems

Development of alternate fertilization programs to mitigate nutrient problems found in long-term organic production systems

In long-lived organic blueberry production systems, nutrient imbalances caused by some fertilization and mulching practices can reduce yield and plant health. The ability to balance nutrient levels and thus improve productivity over time was evaluated in a mature planting of ‘Duke’ and ‘Liberty’ that had previously been used to study different mulching practices and various rates and sources of fertilizer. The prior fertilizer treatments were feather meal and fish emulsion, each applied initially at “low” and “high” rates of nitrogen (N), 29 and 57 kg·ha-1 N in 2007–08 and then increased incrementally as the planting matured to 73 and 140 kg·ha-1 N in 2013–2016. Mulch treatments included sawdust (9-cm deep), yard-debris compost (4-cm) + sawdust (5-cm) and weed mat. In winter 2016-17, existing weed mat was removed from plots where it was present, and new weed mat was installed on top of any existing organic mulches – thus changing the mulch treatments to weed mat (over bare soil), weed mat over sawdust, and weed mat over compost + sawdust from 2017–2020.

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Read more about the article Diversity of Pseudomonas syringae and diagnosis and management of bacterial canker on blueberry

Diversity of Pseudomonas syringae and diagnosis and management of bacterial canker on blueberry

Bacterial canker caused by the bacterial pathogen Pseudomonas syringae is characterized by killed buds and stems. The disease can be severe when environmental conditions support growth and infection of tissues in the fall and spring. The disease is especially damaging to young succulent plants. Copper is sprayed onto plants to control the growth of the pathogen and the development of bacterial canker. P. syringae actually refers to a complex group of pathogens, with individual members that have either a wide host range or narrow host range. Surprisingly, little was known about P. syringae causing bacterial canker on blueberry. It was not known if only a single type of P. syringae with a narrow host range caused bacterial canker or if multiple types of the pathogen complex caused bacterial canker. P. syringae can use many traits to cause plant diseases, such as the production of plant toxins or the ability to nucleate ice formation.

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Read more about the article Particle film and Deficit Irrigation: Partners to Enhance Wine Grape Quality and Sustainability

Particle film and Deficit Irrigation: Partners to Enhance Wine Grape Quality and Sustainability

Application of particle film will affect cluster weight and must soluble solids at harvest differently, depending on vine crop load and the level of water deficit. This research shows there is limited considerations for using particle film in wine grape production for water conservation, enhanced productivity, and improved product quality in vines. However, the product does protect berry size and soluble solids in berry if vines have sufficient water and are not in water deficit when product is applied. However, as heat waves continue to rise across vine growing regions, this particle film may be of use on well- irrigated vines if sprayed prior to the extreme heat event. This study shows that on intact fruit clusters the clay particle spray will protect the soluble solids in the berry.

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Read more about the article Dissecting the cause of reoccurring blueberry shock disease

Dissecting the cause of reoccurring blueberry shock disease

In recent years, there has been an emergence of shock-like disease in previously BlShV-affected fields. The recurring disease has been observed for several years in Oregon and Washington, with disease incidence exceeding 50% in some cases. Over the last decade, the use of High Throughput Sequencing (HTS) has become more widely used for plant virus detection primarily because of two important attributes lacking in current technologies: 1. The ability to provide information on virus population structure, including virus variants, of a plant in a single test; and 2. detect viruses and viroids that have no known laboratory test, also called novel viruses (Villamor et al., 2019).

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Read more about the article Developing commercial blueberry cultivars adapted to the Pacific Northwest and that may tolerate Blueberry shock virus and testing new selections and cultivars from other programs

Developing commercial blueberry cultivars adapted to the Pacific Northwest and that may tolerate Blueberry shock virus and testing new selections and cultivars from other programs

Blueberry shock virus (BlShV) is a serious problem in blueberry production in the Pacific Northwest (PNW) region of North America. Infection occurs during bloom and the virus moves into other parts of the plant in an uneven but steady manner and may take several years to become fully systemic in mature bushes. In the year after infection, emerging flower and leaf tissues die rapidly at full bloom followed by regrowth. Once symptoms have been exhibited in all parts of the plant, the plant remains asymptomatic in subsequent years. Infection in young plants of some cultivars can stunt the plant for the remainder of its life, however, more typically production is lost for one year. While there appears to be no immunity as tested by grafting, it has been recognized that the rate of infection varies among genotypes. Plants in the HCRU breeding program and at the NCGR, have been tested regularly by ELISA for BlShV, in some cases for nearly 20 years, and germplasm that is particularly slow to become infected has been identified. At Oregon State University, North Willamette Research and Extension Center (NWREC), ‘Legacy’ , ‘Toro’, ‘Bluecrop’, ‘Baby Blues’, ‘Darrow’ and all rabbiteye cultivars have tested negative for BlShV for over 10 years while growing among many known positive plants. On the other extreme, ‘Berkeley’, ‘Bluegold’, ‘Brigitta Blue’, ‘Nui’ and ‘Spartan’ tested positive in the year following their 1st bloom. At the NCGR, ‘Bladen’, ‘Harding’, ‘Lateblue’, ‘Legacy’, ‘Razz’, US 612, US 693, US 845, and US 847 all tested negative after 20 years in the field. ‘Toro’ and ‘Bluecrop’, which had tested negative after 20+ years at NWREC, were positive at the NCGR, as were many Rabbiteye cultivars. Crosses will have been made among genotypes that are slow to test positive for BlShV to try to develop this trait in cultivars.

Continue ReadingDeveloping commercial blueberry cultivars adapted to the Pacific Northwest and that may tolerate Blueberry shock virus and testing new selections and cultivars from other programs
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