PSI Bulletin: September 2023
No. 9/23 SUBSCRIBER EDITION: please go to potatostorageinsight.com/subscribe to sign up
Welcome to September's Synopsis, PSI's update of the latest news, technical content and information from the world of potato storage.
September is a big month for most of us as we embark on another crop's journey with stores being loaded and a full season's work ahead of us. So, this month's Best Practice slot is looking at how to get everything right to minimise risk and maximise returns from that new storage season. Our Technical Insight feature has information about sprout suppression options which we plan to expand upon as we head through the early winter months.
Recent weeks have seen some drier and definitely warmer conditions coming into play on the back of a pretty wet period. But the heavy showers are still around and the combination of warm and wet conditions increases risk for crops going into storage.
Variability appears to be high between crops and, in some cases, within crops in individual fields which always adds a layer of extra challenge for store managers.
Managing diseases and defects will be a key element of pre-harvest management and store managers will need to be on the lookout for problems such as hollow heart which are expected to be a product of some of the very large and green canopies that have persisted into the autumn.
There is a consensus that rots will also be present this harvest so please be vigilant for blackleg and blight in particular (these have been reported quite widely in recent weeks) whilst there is also potential for issues such as dry rot, pink rot and watery wound rot to be around depending on local temperatures and moisture status prior to (and at) harvest. For assistance on disease ID, please go to the AHDB archive or speak to Adrian on 07970 072260.
POTATO STORAGE INSIGHT (PSI) ACTIVITY
Caythorpe Potato Breeders Days
PSI ventured over to Sleaford to this event at the end of August to catch up on some of the developments from the breeding companies.
It was good to see some positive attributes in the new stocks for addressing some of the major current 'issues' such as PCN resistance and, in the same way, it was encouraging to see some seed-houses (not all) making a play of new varieties' dormancy and storage capabilities (above and right).
This is something that has often been pretty low in the selection 'pecking order' but, with ever-increasing storage costs and less effective chemistry available for use in store, we need the back up of good genetic traits to tackle some of the basic challenges facing today's producers.
Vegetable Farmer
Adrian Cunnington (right) featured in the September edition of Vegetable Farmer, in an article entitled 'Getting the most from the currently available sprout suppressants'.
You can find more details on the article on the PSI website here:
Or read on to see our Technical Insight feature for more on early use of sprout suppressants,
BP2023 seminars
A reminder that we will be a contributor to the seminar programme which will return at this year's BP2023 event, The show is again being held at the Great Yorkshire Showground site in Harrogate on 22 & 23 November.
The storage seminar is on Day 1. PSI's Adrian Cunnington will be speaking on energy efficient management of stores and will also chair the session on optimising use of sprout suppressants featuring an expert panel of Jeff Beever (McCain), Gary Collins (PI) and Richard Baines (LWM). Tickets can now be booked via the event website and registration is FREE.
BEST PRACTICE for September/October
Are your crops ready to store?
Around my area in south Lincs, I am seeing a lot of crops at various stages of desiccation (below) and the concern at the start of lifting is that crops are only harvested when they have sufficiently 'set' skins to withstand handling.
The tried and tested 'thumb test' is still a decent way of assessing skin suitabillity.
If the harvesting process starts to remove the skin to any significant degree, that is bad news. Curing is not a substitute for the loss of tuber skin and, if crops are lifted too soon, they will lose moisture readily and be at much greater risk of infection. They may also be more vulnerable to damage from early application of sprout suppressants (see Technical Insight).
Managing stores for loading
Crops will want to come into stores that are, ideally, at temperatures just a little cooler than the crop itself. It is fine to pre-cool stores (eg prepack storage) before loading to get the store fabric, especially the floor, down to temperature (be aware this might make it sweat) but as long as the air temperature is back up within 3 or 4°C of the crop and the potatoes can be kept dry and free from condensation, this doesn't matter.
Try to track field temperatures in store where you can, lowering the set point as the ambient temperature declines over harvest.
Dry, dry, dry!
It is almost impossible to over-stress the importance of drying when dealing with freshly-harvested potatoes heading into store.
Quite simply, as a starting point, rained-on potatoes do not store (so I hope those boxed-up spuds on the back of the trailer in the new Walkers ad aren't heading anywhere near one!).
Beyond that, we are talking about crops which are coming out of 'dry', damp, moist or wet soils but are hopefully devoid of 'free' moisture. These all need to be ventilated as soon as possible as even crops from dry soils will be respiring quite heavily so there will be moisture around once the crop makes it to the store. Over and above that, there will often be some excess moisture to remove and this is best achieved by using ventilation to evaporate the moisture. For this to be effective, that means getting air into contact with the crop.
Remember that air takes the path of least resistance, so blowing it randomly around a small stack of boxes in the middle of a big shed is not going to work well. Ideally, stack the boxes across the shed to ensure air has to pass through the pallet slots. If you need to stack differently try to isolate the air to a part of the store to maximise flow through the crop. Keep the air moving through the potatoes until any surface moisture is removed. Please also note that wherever we are evaporating moisture to dry crop, it will also result in some degree of cooling due to the latent heat of evaporation (the same as you feel if using a wet finger to detect the direction of the wind!).
Once crops are dry, there is less pressure on dealing with temperature stabilisation and, indeed, for many crops - especially those destined for processing - there is no need to reduce temperature quickly. That said, as a rule of thumb, stores should be being brought down to holding temperatures within a month of loading. Extended periods for loading that are beyond this will mean that something is being compromised. Often, if that means waiting for a late crop to come into store, it's the potatoes already in the store from day one that will suffer most and they may well be the most valuable and/or the crop destined for long-term storage.
When crops are in store, make a point of going back and checking on them regularly until they are stabilised. If there is any disease around, it will often make itself known quickly and you need to be on the ball to deal with it (usually by ventilating), not waiting until harvest is over to discover rots that it's too late to do anything about.
If, as we move into a new storage season, you'd like to discuss how best to handle a particular situation over intake or to get advice on how your stores' drying or pull-down strategy can be further optimised, please get in touch with Adrian Cunnington at PSI on 07970 072260.
TECHNICAL INSIGHT
OUR SPROUT SUPPRESSION TOOLBOX HAS EXPANDED BUT CLARITY IS STILL NEEDED ON OPTIONS
Using the right chemical and getting one good application at the right time, can get good sprout control for a longer period than perhaps was thought possible when CIPC was first banned. Heading into the 2023/24 season, we have spearmint oil (Biox-M®), orange oil (ARGOS®), 1,4-dimethylnaphthalene (known as DMN and sold as 1,4 SIGHT®), ethylene and maleic hydrazide (MH) all as part of the armoury.
The sheer number of products offers a complex variety of combinations that can be used . This has to sit alongside the use of new application techniques and makes for a complicated landscape of sprout suppression solutions about which we know very little, especially once we start talking about different sequences.
Add to that the differing types of stores being used across the industry plus rapidly-changing store management strategies to deal with rising energy costs and the way ahead can be far from clear.
Those growing on contract are perhaps in the best place as supply chains are asking their growers to follow specific, selected options for sprout suppression which gives those supplying these markets some focus.
Part of the learning challenge is about how to maximise efficacy and flexibility by understanding how to use different products in combination within the season. But we need to tread carefully as there are already growers whose strategies have come unstuck due to unforeseen consequences after using some of the new products. Until there is further data from testing, it is probably best to keep approaches as straightforward as possible.
As a good foundation, MH plays an important role in the sprout suppression toolbox as it provides useful residual control of sprouting. That is the control that we need between doses of less persistent, contact action products,
Any of ethylene, spearmint, orange oil or DMN can be used in the store after a field application of maleic hydrazide. Excluding ethylene, any need to re-apply should be moderated by the MH which is important in managing costs, but it will vary with variety and temperature.
DMN has had only one season's use in the UK and we only have the original label to work to. It has been successfully introduced in processing but detailed information on its use on some specific varieties remains lacking. The product is a dormancy enhancer rather than simply a means of burning off the sprouts so it works best when applied early but it does have a 30-day harvest interval. (DormFresh have a long term plan to change this but nothing will change in the near future). Therefore, if you need some flexibility on when you take the crop out of store, it may be better to switch to spearmint or orange oil as a final treatment before sale.
With all sprout suppression products it is essential that the labels and best practice recommendations are followed closely. For example, ventilation is necessary to circulate the mint, orange and DMN products as part of the application process, and it is important to understand how this has changed fpr the new generation of materials; we are not just doing the same as we did with CIPC. A good starting point is to have a discussion with your BASIS-qualified storage advisor or NAAC contractor before the beginning of the season and/or you can call us here at PSI on 07970 072260.
Key points for effective sprout control
Plan applications in advance, ensuring the correct timing and that conditions are adequate such as uniform store temperatures
Engage in early and detailed conversations with your advisor or contractor prior to harvest to discuss factors such as box stacking patterns and how full the store needs to be for effective application of the suppressant
Avoid placement of crop adjacent to application points because if the air is unable to mix with the chemical, it increases the risk of condensation or chemical fall-out and subsequently scorch
Ensure best practice is followed at all times. Always maintain recommended application rates. Big problems such as internal sprouting can arise if corners are cut.
EXPORTS OF SEED POTATOES TO NORTHERN IRELAND CAN RESUME AFTER BREXIT BAN - BUT NO PROGRESS ON EU
Farmers Weekly reports: Defra has been accused of being “asleep at the wheel” on the issue of seed potato exports to the EU. English, Scottish and Welsh seed potato growers have been unable to export to the EU since 2021, after the bloc denied access to the market over concerns about the product remaining aligned with European standards post-Brexit. According to FW, the Scottish seed potato industry accounts for three-quarters of UK production and is worth about £112m/year.
Defra has recently confirmed exports of seed potatoes to Northern Ireland can resume from 30 September 2023, but progress on resumed access to the wider EU market has stalled.
In response to a letter from Richard Thomson, SNP MP for Gordon, minister Lord Benyon said the issue had not been raised with European officials since March. “I worry that it provides an indication of the importance – or lack of – that the Government attaches to restoring Scottish seed potatoes, renowned the world over for their quality, to their rightful export markets,” said Mr Thomson. “Defra has effectively been asleep at the wheel for months when it should have been driving the negotiations to get our markets back.”
A Defra spokesperson said: “Under the Windsor Framework, plants and seeds can once again move easily within the UK, ending restrictions that hampered consumer choice and damaged business. “This includes removing the prohibition on the movement of seed potatoes on 1st October and we will work with industry to ensure plant and seed movement schemes are as beneficial as possible”.
SNIPPETS
INDUSTRY STALWART RETIRING!
It is with a slight element of disbelief that I'm including a short piece here to inform you that Dr Philip Burgess of scottishpotatoes.org is retiring at the end of this month. Phil has been a well-known feature of the potato landscape in Scotland and England over the years, if I can put it that way, and will definitely be very much missed. He doesn't seem to have been in his dual role at SRUC & JHI that long "looking to develop whole industry initiatives around key challenges", and he certainly seems far too young, but he has decided to call time on his distinguished career in 'tatties'.
Delving into some old AHDB records, I note that Phil studied Agricultural Botany at the University College Wales, prior to gaining his PhD working on the spread of potato blackleg at Queens University, Belfast.
He has had a varied but impactful career working in potatoes across the spectrum from basic science to applied research and also spent several years overseeing delivery of crops to supermarkets in the hard-nosed commercial world. His myriad skills have been deployed on both a technical and commercial level for SAC, MBM, Co-op, AHDB and the relatively recent SRUC/James Hutton initiative mentioned above.
Phil was a highly-valued colleague of mine in his time running the Knowledge Transfer function in AHDB where his breadth of experience gave him a good feel for the balance between R&D theory and commercial reality, something which is so key to translating trials results into practical, useful and cost-effective guidance for growers to adopt. I wish him well in whatever he chooses to do - spending time with his family and travelling to some parts of the globe off the beaten track will be high on his agenda I am sure, His phone number is apparently staying the same and last time I checked he was still on X/Twitter as @tatophil.
Thanks and good luck, Phil.
AC
EXCITING STORAGE NEWS ON THE WAY...
As you are all keen subscribers to storage news, we'd like to let our readers know that you should be on the lookout for details due to be released in the coming days of a new collaborative, cross-industry storage initiative that is currently being set up... We'll post the information on our blog page at www.potatostorageinisght.com/blog and also include it in our next edition of Synopsis.
FORTHCOMING EVENTS
Potato events in the coming weeks and months include:
November
Sun 12 - Sat 18 AGRITECHNICA, Hannover, Germany
World-leading trade fair for agricultural machinery
Wed 22/Thu 23 BP2023, Harrogate, Yorkshire, UK
Biennial industry-wide exhibition and knowledge transfer opportunity for everything to do with potatoes. Seminar programme includes storage. Registration now open.
December
Tue 12 - Wed 13 CUPGRA 34th Annual Conference, Cambridge. Save the date!
2 day ticket: CUPGRA members £138, non-members £281;
1 day ticket: members £72, non-members £165
2024 International Potato Events
10-11 Jan POTATO EXPO, Austin, Texas, USA
23-25 Jan WASHINGTON/OREGON POTATO CONFERENCE, Kennewick, WA, USA
23-26 Jun WORLD POTATO CONGRESS, Adelaide, Australia
7-12 Jul EAPR 22nd TRIENNIAL CONFERENCE, Oslo, Norway
24-26 Nov INTERPOM '24 Kortrijk, Belgium
Remember you, or a colleague, can subscribe to Synopsis at any time by going to potatostorageinsight.com and clicking on SUBSCRIBE. We can also now take payments by credit card. Call Adrian on 01406 364795 or 07970 072260 if you have any questions.
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Synopsis is published by Potato Storage Insight Ltd., 45 Main Street, Gedney Dyke, Spalding, PE12 0AJ. UK.
© Potato Storage Insight Ltd. 2023
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