23 Nov 2020
Citrus Exports

SA citrus exports to US up 50%, set to grow even further as local growers now have access to more ports

More South African citrus fruits will be heading to the US under a new agreement. Early this month, the US government announced the opening of several new ports for South African citrus fruits. The US department of agriculture’s Animal and Plant Health Inspection Service approved the use of additional ports for South African citrus on November 5. The US embassy said the facilitation of the trade between the two countries provided flexibility to American retailers and wholesalers, lowering transportation costs and broadening the reach of South African citrus to other regions.

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23 Nov 2020
Crop Manipulation

Crop manipulation uppermost on the minds of South African citrus growers

South Africa’s Limpopo and Mpumalanga citrus production regions enjoyed mild temperatures during an “almost ideal” fruit set this spring on all cultivars, including on seedless Valencias. Regions that have been receiving sub-average rainfall for years now, had substantial rain early last month. “Producers need to be cognisant of the potential negative impact of too high fruit set, of which a reduction in fruit size is the most problematic,” the South African citrus industry’s technical service Citrus Research International reminds growers.

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23 Nov 2020
Flooding

Impacts and management of flooding and waterlogging in citrus orchards

The recent heavy rainfall and flooding events in NSW may cause some immediate damage to trees, but may also have significant long term impacts on citrus orchards, particularly those planted on heavy soils or those with impeded drainage. Previous flooding events in the MIA Previous flooding and high rainfall events occurred in the Murrumbidgee Irrigation Areas (MIA) in the 1930’s and 40’s (during the winter months) and the impacts of those events, combined with a tendency to over-water resulted in considerable decline in tree health and the death of many trees. Survey and research work undertaken by Dr. Lilian Fraser concluded that one of the main causes of tree death and decline was due to infection by the root rot fungus Phytophthora citrophthora.

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23 Nov 2020
Climate Change

Potential climate change impacts on citrus water requirement across major producing areas in the world.

Understanding how potential climate change will affect availability of water resources for citrus production globally is needed. The main goal of this study is to investigate impacts of potential future climate change on citrus irrigation requirements (IRR) in major global citrus producing regions, e.g., Africa, Asia, Australia, Mediterranean, Americas. The Irrigation Management System (IManSys) model was used to calculate optimum IRR for the baseline period (1986–2005) and two future periods (2055s and 2090s) subject to combination of five and seven temperature and precipitation levels, respectively. Predicted IRR show significant spatio-temporal variations across study regions. Future annual IRR are predicted to globally decrease; however, future monthly IRR showed mixed results.

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20 Oct 2020
Carbohydrate Shortage

Hormonal regulation of fruitlet abscission induced by carbohydrate shortage in citrus

Like many fruit trees species, citrus trees blossom with high profusion and thereafter exhibit massive fruitlet abscission. Current evidence indicates that this process is under hormonal and metabolic regulation (Gillaspy et al. 1993). In citrus, it has been suggested that after hormonal activation of initial fruit growth subsequent development is mostly supported by nutrient supply (Talon et al. 1997). Thus, once mineral and water requirements are satisfied, competition for photoassimilates is thought to be responsible for fruit drop (Moss et al. 1972; Powell and Krezdorn 1977; Goldschmidt and Koch 1996).

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20 Oct 2020
Managing Salinity in Citrus

Managing Salinity in Citrus

Although citrus (Citrus spp.) is sensitive to salinity, acceptable production can be achieved with moderate salinity levels, depending on the climate, scion cultivar, rootstock, and irrigation-fertilizer management. Irrigation scheduling is a key factor in managing salinity in areas with salinity problems. Increasing irrigation frequency and applying water in excess of the crop water requirement are recommended to leach the salts and minimize the salt concentration in the root zone. Overhead sprinkler irrigation should be avoided when using water containing high levels of salts because salt residues can accumulate on the foliage and cause serious injury. Much of the leaf and trunk damage associated with direct foliar uptake of salts can be reduced by using microirrigation systems.

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23 Sep 2020
CYVC symptoms on young lemon leaves

Two new citrus virus diseases found in Turkey

“Two serious viral diseases are affecting Turkey’s citrus cultivation and threatening all the Mediterranean countries”. This was reported by Antonino Catara, former president of the International Organisation of Citrus Virologists.

“One of the two diseases – continued the scientist – is the Citrus Chlorotic Dwarf CCD, which mainly affects lemon and grapefruit plants, but also marginally mandarin and clementine plants. The viral infection has a significant impact on the yield and quality of the fruit, as well as on the crown’s vegetative development, due to the short internodes”.

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23 Sep 2020
Citrus

Citrus industry negotiates a new trade deal

Cape Town – After eleven years of negotiations, South Africa’s citrus industry has been given the go-ahead to export to the Philippines, with the signing of a work plan between the Department of Agriculture, Land Reform and Rural Development, and the Philippines Bureau of Plant and Industry.

Agriculture Minister Thoko Didiza made the announcement yesterday as the South African citrus industry estimates that close to 500 000 tons of additional citrus would be available for export by 2024.

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23 Sep 2020
Coldling Moth

South Africa takes proactive FCM measures with its EU citrus exports

For the first time since 2018 when the South African citrus industry introduced its False Codling Moth Management System, the citrus industry has had to intervene in its normal functioning to manage false codling moth.

The decision to strengthen the shipping protocol for South Africa’s oranges for the rest of the season, on very short notice, is made possible by the agility of its systems approach, says Deon Joubert, Citrus Growers’ Association envoy to the EU. The system’s requirements for continuous, thorough orchard and fruit monitoring had made it clear to the industry that there was a lot of false codling moth activity this year.

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23 Sep 2020
Citrus rootstock evaluation

Citrus rootstock evaluation utilizing UAV-based remote sensing and artificial intelligence

The implementation of breeding methods requires the creation of a large and genetically diverse training population. Large-scale experiments are needed for the rapid acquisition of phenotypic data to explore the correlation between genomic and phenotypic information. Traditional sensing technologies forfield surveys and field phenotyping rely on manual sampling and are time consuming and labor intensive. Since availability of personnel trained for phenotyping is a major problem, small UAVs (unmanned aerial vehicles) equipped with various sensors can simplify the surveying procedure, decrease data collection time, and reduce cost.

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