Spud Special: Ware potato crop quality a concern

Potato harvest is well underway; indeed clients in Cheshire are almost finished. Gross yields of both seed and ware seem to be higher than average, hardly surprising when you consider the amount of sunshine the crop received during June and July. It just goes to show the importance of achieving full ground cover by the longest day.

Whilst gross yields are excellent, I think it is a different story regarding marketable yield of the ware crop. Wastage levels are extremely variable: greens, tuber blight, pink rot, blackleg and water logging are all showing up in pre-harvest quality assessment digs, therefore it is vitally important to check what problems are likely and manage them accordingly.

Where tuber blight and soft rots are concerned, making sure that full skin set has been achieved is crucial and any damage or scuffing will allow bacterial infections to spread. Skin set is taking surprisingly long in some crops and black dot levels are likely to increase – a particular problem in packing crops. Avoid excessive handling if you have identified these problems, harvest direct into boxes as opposed to putting over a grader if that is an option. Soil conditions are ideal at present, unlike 2-3 weeks ago when they were very dry.

Crops harvested into store during this time have varying degrees of bruising, so check by regularly hot boxing tubers from different points of the harvesting process to establish any weak points. Carrying out an assessment of how the crop will behave prior to harvest will help ease decision making, if you know the crop is likely to bruise adjustments can be made to harvester settings.

Soil temperature is still on the high side, so it will be important to take field heat out of crops as soon as they are placed in store, aim to fill stores as quickly as possible, curing and cooling them down to their target temperature at no more than 0.5C per day.

For those who use CIPC (chlorpropham) please make sure that you are fully aware of the latest stewardship guidelines regarding all aspects of application.

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