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Storage Bulletin - May 2016

Publication Date: 
10 May 2016

TWO KEY SOURCES OF STORAGE CONCERNS

As the storage season moves into its final phases, it has become increasingly apparent that many of the problems that have been experienced in stores this season have had their root in two key areas: seed quality and skin set.

Ensuring good skin set was difficult in 2015 due to the wet end to the growing season and may have contributed to some of the rotting problems encountered in storage this year. A major tool for achieving this is currently under threat as the EU authorities have been reviewing the suitability of diquat, our main desiccant, for re-registration. AHDB is actively working with the product manufacturers and approval holders to put as strong a case as possible for its retention, as it is a key chemical on which the industry relies enormously.

Seed quality is another aspect which perhaps needs a bit more attention on the part of the ware grower as problems like blackleg and skin spot, which have also been very prevalent this season, can often develop from seed-borne infections.

With most remaining crop coming out of store soon and the subsequent one probably already in the ground, the best place to focus is probably on seed for next year. Building a rapport with your seed supplier, making it clear what you are looking for from your seed supply and even taking the trouble to visit your supplier to see the seed crop for yourself around harvest time can all be worthwhile. This may not be realised until many months later when you harvest that daughter crop in autumn 2017 and are looking to get the best from it in terms of storage quality. 

 

A function of old age?

There is some emerging evidence that crops remaining in storage are showing some clear ‘ageing’ effects, perhaps as a result of high temperatures last summer and autumn. These symptoms seem to be more prevalent than usual with some reports of declining fry colour (perhaps due to senescent sweetening in susceptible varieties) and a high risk of blackening on handling, peeling and washing in some crops. This is caused by degradation of membranes in the cells of the tuber*; it results in leakage of cations which are involved as pre-cursors in the formation of black pigmentation. The cells outside the vascular ring appear to be most susceptible, and this can sometimes be so even if they have not been subjected to any form of impact.

Regular assessment of crops to ensure they continue to meet market specifications is a valuable part of store management best practice.

*Lærke, PE; ER Brierley and AH Cobb (2000) Impact-induced blackspots and membrane deterioration in potato (Solanum tuberosum L) tubers. J Sci Food Agric 80:1332-1338.

 

Store preparation for next season

As stores become empty, it is often worthwhile to take advantage of a time of slightly lesser workload to prepare them for next season. Routine clearance of crop debris is important, not forgetting any ventilation tunnels or underfloor ducts. If there has been any wet rot present, steam cleaning to clean any areas contaminated by exudate is recommended. A disinfectant can be added if necessary. If the plan is to use a peracetic acid treatment (eg Jet 5) ensure dust and organic material is thoroughly removed as otherwise it will rapidly deactivate the product.

Other routine tasks that should be considered include verification of crop probes, both in terms of their condition and the accuracy of their reading; servicing of any mechanical equipment - especially louvres/flaps - and repair of boxes.

Cold stores should be serviced by a refrigeration specialist to clean evaporator and condenser coils and to check the refrigerant charge. Please note that R22 systems can no longer be topped up and the refrigerant will need to be replaced if this is deficient.

Remember that next season is the last in which CIPC can be applied without the use of ‘active recirculation’ so, if at all possible this summer, it would be prudent to look at the installation of a suitable fan for circulation of fog rather than leave it until the last minute next year. Call the AHDB Potatoes Storage Advice Line on 0800 02 82 111 for additional guidance.

 

CIPC stewardship limits for 2016/17

In line with recent years, there will be a continued reduction in maximum CIPC doses for the coming storage season. Processing potatoes will be limited to a maximum of 42g per tonne whilst fresh potatoes will be capped at 24g per tonne, unless they are stored at 5°C or less, where the existing limitation of one dose per season will continue. Visit www.cipccompliant.co.uk to ‘Be 2017 Ready’ and for other CIPC stewardship information.

 

Sutton Bridge developments

AHDB Potatoes’ sector board has appointed Graeme Byers, NPD Director of Tayto Ltd, to the Sutton Bridge Advisory Committee to take the place of Steve Billings, who is retiring. We thank Steve for his valuable input to Sutton Bridge.  Graeme joins Archie Gibson of Agrico (UK) and AHDB Potatoes Board members Dave Chelley (PAS, chair); Mark Taylor (IPL) and Fiona Fell in providing oversight on matters of strategic development, financial and business management for SBCSR.

It is good to be able to report that construction began on 3 May of the first phase of the capital development plan for the site. Ten new experimental stores are being built to service the new Centre for Crop Health and Protection (CHAP) of which AHDB is a partner. Read more about CHAP at http://bit.ly/1N3lnH4

As part of a clearance programme linked to this project, AHDB has a significant number of good quality, used hand riddles of varying sizes available free of charge to levy payers on a first-come, first-served basis. These riddles are the circular type, originally manufactured by Barretts of Boston, with a wooden rim and wire mesh. Collection would be from SBCSR at PE12 9YD by arrangement. Call Hannah Futter on 01406 351444 for further details.

 

AHDB Strategic Potato farm programme

AHDB has announced that it is expanding its demonstration potato farm initiative this spring. Two new SPot sites have been launched at Elveden in Suffolk and near Blairgowrie in Perthshire to join the existing SPot Farm in Staffordshire. Dates for open days are now set for all sites – so please come and see the science in action!

Last year, James Daw and his son Sam, were instrumental in getting the SPot programme off the ground as the first ever hosts with a hugely successful initial array of events. SPot Farm West will continue at their business on a new site at Thorpe Constantine in 2016 and some storage features will be included for the first time in their programme. A farm walk is planned for 30 June and an open day on 19 July. Further farm walks will be announced for August and September.

SPot Farm East commenced in April at Elveden Farms with the backing of 50% funding from GCPC’s Eastern Agri-Tech initiative. An open day will take place on 5 July together with a programme of farm walks later in the year (see graphic).

The Scottish SPot Farm (co-funded by Scottish Government) launches early with a 24 ha (60 acre) field of Maris Piper at Bruce Farms, Perthshire. An open day will take place on 12 July.

European Association for Potato Research

There is still time to register for the EAPR Post-Harvest Section Meeting to be held in Wageningen, the Netherlands on 29/30 June 2016 at which SBCSR will be represented.

Go to http://eapr‐postharvest.eu for details or, for further information, please contact: info@eapr‐postharvest.eu

 

Agriculture & Horticulture Development Board, Stoneleigh Park, Kenilworth, Warwickshire, CV8 2TL.  May 2016. © AHDB

 

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