27 Jun 2023
Flooding

Citrusdal community bands together to get back on their feet after flood

Rain is still falling over Citrusdal where food has had to be flown in by helicopter to stranded inhabitants after the town’s entrance road was washed away, and now the remaining electricity line has also fallen victim to the flood.  It is expected that the rain will ease off from Wednesday. In the port of Cape Town very high swells have meant that vessels couldn’t enter the harbour; there are currently three vessels waiting to come into port.

Repairs to the town bridge over the Olifants River which was washed away are underway, including correcting the course of the swollen river.

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27 Jun 2023

Florida citrus crop drops to smallest in nearly 100 years

The price of orange juice will be going up again after Florida farmers produced the smallest citrus crop in nearly 100 years . It was a tough year for the state’s orange trees, which were hit by bad weather and an epidemic of greening disease, which causes the fruit to be bitter. According to analysts, the US will not be able to lean on Brazil for more oranges, as that country’s production was also affected by bad weather.

Since orange production in Florida has been declining in the past decade, some farmers there are considering switching to other crops.

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25 May 2023
Boron Stress on Citrus

Citrus Physiological and Molecular response to Boron Stresses

Since the essentiality of boron (B) to plant growth was reported nearly one century ago, the implication of B in physiological performance, productivity and quality of agricultural products, and the morphogenesis of apical meristem in plants has widely been studied. B stresses (B deficiency and toxicity), which lead to atrophy of canopy and deterioration of Citrus fruits, have long been discovered in citrus orchards. This paper reviews the research progress of B stresses on Citrus growth, photosynthesis, light use efficiency, nutrient absorption, organic acid metabolism, sugar metabolism and relocation, and antioxidant system. Moreover, the beneficial effects of B on plant stress tolerance and further research in this area were also discussed.

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25 May 2023
Shade cloth over citrus

Mitigation of Heat Stress effects by using Shade Net on Washington Navel Orange Trees grown in Al-Nubaria Region, Egypt

High temperature stress can be detrimental to plants, resulting in reduced fruit yield and increased incidences of fruit disorders. One strategy that farmers can use to maintain or increase their yields in the face of a changing climate is to adjust of farm climate by using shade net on the trees. Such, the use of shade netting on Washington navel orange planted on the sandy soil in Al-Nubaria region, Egypt were studied during two successive seasons, either using a permanent shade throughout all the season or using a moveable shade for certain period from the first of March until the end of June for every season.

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25 May 2023
Citrus Rind

Reduction of postharvest rind disorders in citrus fruit by modified atmosphere packaging

Citrus fruit are relatively non-perishable, and can normally be stored for long periods of 6–8 weeks. However, the development of various types of rind disorders limits the postharvest storage capability, and causes massive commercial losses. In the present study, we found that modified atmosphere packaging (MAP) in “bag-in-box” Xtend® films (XF) effectively reduced the development of chilling injury (CI) as well as other types of rind disorders that are not related to chilling, such as rind breakdown, stem-end rind breakdown (SERB) and shriveling and collapse of the button tissue (aging). In all cases, microperforated films (0.002% perforated area) that maintained CO² and O² concentrations of 2–3 and 17–18%, respectively, inside the package were much more effective in reducing the development of rind disorders than macroperforated films (0.06% perforated area), which maintained CO² and O² concentrations of 0.2–0.4 and 19–20%, respectively.

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21 Apr 2023
Citrus flower and leaves

Changes in carbohydrates and mineral elements in Citrus leaves during flowering and fruit set

Mineral elements and metabolizable carbohydrates in Citrus leaves [Citrus sinensis (L.) Osbeck cv. Washington navel] have been determined from bud sprouting until the end of the June drop and related to fruitlet growth and abscission. Mineral elements in old leaves decreased during the spring flush of growth and reached minimum values at flower opening, coinciding with a peak in abscission. This was followed by a rapid recovery in potassium and nitrogen to the initial values, with little change afterwards. Old leaves accumulate carbohydrates until flowering, and lose them during post-anthesis at a constant rate for more than 4 months; this rate of export is unaltered by the presence of a nearby growing fruit. Inflorescence leaves accumulate carbohydrates and mineral elements during post-anthesis; during the June drop there is an interruption in the accumulation of nitrogen and a net loss of phosphorus, potassium and carbohydrates from these leaves, coinciding with the attainment of the maximum growth rate of the fruit.

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21 Apr 2023
Powerline in South Africa

Farmers could lose R500m this year as load shedding adds to SA citrus export woes

Up to a quarter of South African oranges destined for the European Union (EU) might not be shipped due to the impact of load shedding, in addition to new EU regulations – posing a potential loss of more than R500 million for local farmers this year. This warning went out from the Citrus Growers Association of South Africa (CGA) on Thursday. More than 400 000 tons of SA oranges were shipped to the EU in 2022. The citrus export industry supports 140 000 jobs and generates R40 billion in export revenue annually.

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21 Apr 2023
Wind damaged citrus

Windbreaks – Increased Focus Needed

South-easterly winds coincide with the first 12 weeks after mandarin petal drop. When these winds become more intense between October and December, they can cause up to 87% of the severe wind-scar damage seen in a season. However, says Heinrich Geldenhuys, such losses can be minimised with suitable windbreaks or other forms of wind protection, resulting in higher export volumes of quality fruit. Geldenhuys is a junior researcher who graduated in April 2022 with an MSc in Horticultural Science degree from Stellenbosch University (SU).

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