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PSI Bulletin: Jul 23

No. 7/23 SUBSCRIBER EDITION: please go to to sign up

It's time for the July edition of Synopsis, PSI's monthly update of news, technical content and information the latest developments in potato storage, to hit the streets.

In this month's Best Practice slot, we will be looking at the critical issue of maleic hydrazide application for all those looking for good quality sprout control in storage. Our July Technical Insight talks about potato boxes... and we have a comprehensive events listing at the end of this bulletin.

Since we wrote our June update, the weather has taken a marked turn towards cooler and showery, if not stormy, conditions so overall crop growth should benefit.

Most long term stores are now empty and, if you have yet to find time, it's a good opportunity to review last season's store performance and a chance to attend to some of those persistent wrinkles - such as faulty temperature probes or dirty fridge coils - that need dealing with before next season. It's the right time to get fridges serviced and cleaning is also a key activity that can be done before (cereal) harvest gets underway. In addition to general removal of debris, vacuuming out stores to remove dust and reduce the spore loading in stores that will be holding seed or pre-pack crops is always time well spent.


We've been pretty busy in the last few weeks, undertaking store audits and attending a number of different grower meetings which have been held around the east of the country with more to follow a little further afield in a few weeks' time.

GB Potatoes roadshow

The GB Potatoes workshop held in Wisbech on 20 June was the first real opportunity for growers to get together to get some technical advice and to support this important effort to set up some cross-industry representation to Government and other key stakeholders.

New research stores launch

On 11 July, Adrian was present (below) at the launch of the new ADAS/CHAP experimental stores at Boxworth near Cambridge, which represent the first steps in re-establishing some potato storage research capability after the AHDB Sutton Bridge meltdown in 2021. The consortium behind the initiative is going to be known as Crop Storage & Postharvest Solutions (CSPS) and, in addition to ADAS and CHAP, brings on board additional technical backing from the likes of the National Resources Institute (NRI), James Hutton Institute, SRUC and PSI.

New CHaP stores launch event at ADAS Boxworth
New CHaP stores launch event at ADAS Boxworth (picture: ADAS)

Also present at the Boxworth event was Dr Richard Colgan of NRI demonstrating their new Storage Control Systems P-Pod research monitoring units for placement in commercial or trial stores. The 'pods' allow close monitoring of potato performance, including respiration, in storage and have been developed from the 'Safe Pod' system first trialled at NRI and Sutton Bridge.

Dr Richard Colgan of NRI describes the P-Pod system
New research stores at JHI are now complete

The stores 'launched' at Boxworth are complemented by a further six of the 4 tonne capacity stores that have been built for CSPS at the James Hutton Institute in Dundee (pictured below, right). The stores in Scotland will be managed as part of the Advanced Plant Health Growth Centre.

The facilities at all the CSPS sites are currently being tested before being used 'in anger' for research and trials.

Anyone wishing to avail themselves of the new storage research capability should contact Faye Ritchie at ADAS or Derek Stewart at JHI in the first instance.

Hutchinsons Potato Day

Another event which attracted a good turnout was the Hutchinson's Potato Demonstration Day, held in conjunction with Simon Faulkner of SDF Agriculture, at AH Worth's farm at Holbeach Hurn in south Lincolnshire on 13 July.

The site is being run to look at issues that not only affect potato growers on the Lincolnshire silts, but are common to growers across a range of soil types. The event demonstrated a wide range of new varieties and Simon spoke about their tolerance and resistance to PCN, with Darryl Shailes and colleagues from Hutchinsons contributing on their response to post-emergence weed control. It is hoped that it may be possible to store the produce from the plots through to spring 2024.

Martyn Cox of Blackthorn Arable also gave an update on wireworm, long regarded as a pest of potatoes grown in grass rotations, but now an increasing problem across all rotations.

BEST PRACTICE for July/August

If you'd like to discuss how well your store is working and to get advice on how you develop your storage strategy or how a particular store can be further optimised, please get in touch with Adrian Cunnington on 07970 072260.

Late July moving into August is a critical time for considering maleic hydrazide application.

Most of our post-harvest sprout control options have little or no residual activity against sprouting – this is the control you get between applications of contact products like spearmint or orange oil.

This residual element can be so key for long term storage and therefore the role of MH cannot be underestimated in the "post-CIPC era". Conditions this year are expected to make its use considerably easier than last season.

MH is available as a a number of products eg Fazor, Crown, Itcan etc for application as a spray treatment. It is important to follow individual labels for your choice of product.

Application guidelines issued by Certis Belchim for its Crown MH product state that:

  • MH is a large molecule and needs time to be absorbed by the plant's leaves.

  • It is important to avoid hot and dry conditions where the spray solution dries very quickly, or rain showers where solution can be diluted.

  • MH should be applied when temperatures are below 25ºC, and no rain is forecast or irrigation scheduled, for at least 12 hours (and ideally 24 hours).

Further guidance

Water volume is important with maleic hydrazide as good uptake by the plant is key to its effectiveness. Best results are achieved with volumes of at least 400L/ha. This helps to keep the leaf wetter for longer and increases the uptake of MH into the plant.

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