Potato crops are now safely in store in most areas of Scotland. The level of soil in some stocks is very high, although the clearer and stiller autumnal air days have been helping with the task of drying the crop and starting to pull the crop temperature down. The continual use of crop drying – in many cases by positive ventilation – is crucial in ensuring a successful out-turn.

 

Many export crops for seed and ware are now being graded out of store. In general, these crops have been well received by overseas inspectors. But the perception and interpretation of different diseases and tolerance levels is a source of discussion and bewilderment in some grading sheds.

 

The main problem being removed on the grader is potato common scab and this is understandable given the dry conditions around tuber initiation. There are few rots being reported, although the later lifted stocks may tell a different story.

 

In store, recording the temperature, noting the differentials between the areas of the store and monitoring the disease levels are key in helping to answer any unexplained problems. 

 

Meanwhile, we are now starting to plan for next year’s crop. Field selection before the potato crop is becoming increasingly important and knowledge of the crop out-turn and problem areas the previous time that the field was cropped will be key a successful outcome.

 

A tool increasingly at our disposal is the range of soil tests that are now available to establish soil nutrient status (pH,P,K,Mg) and soil-borne disease levels, including free living nematodes, tobacco rattle virus and potato mop-top virus.

 

There are also newer tests for black dot and powdery scab. The confidence level with the results obtained from these soil tests and the prediction of tuber disease levels is giving a stronger correlation every year as more data is gathered.