Recently in Spud Special Category

Further heavy showers has hampered planting progress, particularly for those with more bodied land, the dilemma being do you move soil to dry it out and run the risk of it getting wet again, putting you back to square one.

Conversely some growers in Cheshire are just about to start harvesting Maris Bard, grown under fleece. Quality and tuber numbers look good, the problem will be that crops not grown under fleece have a lot to do to follow on.

Applying pre-emergence herbicides in some parts of the country is proving challenging with regard to actually getting on to the fields. In some cases 100% emergence has occurred before application has been made. This can be risky as you are relying on the contact action of diquat or carfentrazone to take the foliage back to ground level to avoid residual uptake. Be aware that some varieties are extremely sensitive to metribuzin post emergence, so if in doubt use alternative actives.

If you are a potato grower in Scotland then you may now start to wonder what you have done wrong in the world. The only comfort is that it's not just Scottish growers. Planting is varied with many seed growers still to start while some ware producers have over 60% in the ground.

Crops planted in March into dry warm soils appear to have gone through their lag phase prior to the cold, wet April. These crops have or are emerging under fleece and in open crops. Those crops planted just before the heavy rains have moved little and their destiny hangs in the balance with an increased risk of poor emergence, rhizoctonia and free living nematode feeding damage.

When planting does restart growers need to think about strategy. There could be a benefit in increasing spacing in ware crops by 10-15% in all but very low tuber number varieties.

Unlike last season size is likely to be at a premium and wider spacing will provide crops with more chance in getting to size without extending the harvest window and jeopardising quality. There is no advantage to reducing planned nitrogen other than in indeterminate varieties or processing crops where sugar stability is required.

Planting in Cheshire got off to a flying start at the end of February and early March. Soil conditions were exceptionally good with chitted first earlies, covered with fleece, emerging rapidly.

 

Even planting in Lancashire got off to a relatively early start. Most growers in Yorkshire and the Borders made a start during the third week of March, planting in to very good soil conditions.

 

April seems to have given us all a reality check with much-needed rain and cold weather slowing things down. Soil temperatures have plummeted with sprouts hardly moving over the past two weeks and there has only been a little root development.

If there is one way to sum up the season ahead it is one word: unpredictable. To illustrate this, the heat wave in Scotland at the end of March has vanished and April has started with >15 degree drop in temperature.

By the time you read this some of the planted ridges may well be covered by a couple of inches of snow. Good progress had been made in the later end of March by most growers subject to attitude to frost risk and whether they had finished cereal drilling.

While Scotland will never be in drought it has experienced an unusually dry winter. Growers that were patient and waited for land to dry to plough have reaped the benefit, with soils with good structure, comparatively dry and in good condition to plant with high soil temperatures .

Early plantings have gone in well. Dry soil conditions may increase the risk of soil borne Rhizoctonia particularly if soil temperature drops and delays emergence. Growers should consider use of azoxystrobin in furrow where fields have a history of Rhizoctonia problems.

Harvest for most is finally finished although a few large growers are still struggling and there a number of fields that can not be lifted. While growers are now preoccupied with preserving quality in store and grading seed for export, it is worth considering next season.

This season has shown that marginal land is marginal for a reason and this is also true for virgin land. While combinable crop growers reduce costs and increase profitability by increasing scale, most potato growers need to reduce the number of marginal fields they plant instead. 

Furthermore, it has also shown that if a field has a past history or is high risk for powdery scab then there is only so much variety, and in the case of seed growers fluazinam, can do to reduce it. These fields also run the risk of potato mop top virus that has also proved problematic.

Most, if not all crops, have now been harvested with some huge yields reported. Quality is variable with the main challenge ahead probably marketing and moving the crop.

 

I am hearing reports of some store breakdown, particularly where harvest into store continued during the very hot and dry weather in September. The first ground frost of the autumn on 20 October resulted in tuber temperatures dropping 3-4C almost overnight.

 

This resulted in a massive increase in bruising levels in a number of varieties. Therefore, if you have not already sampled your stores for quality I suggest you do so, paying particular attention to the areas of store that were loaded around that date.

 

Better harvesting weather recently (light rain rather than torrential) has enabled better progress to be made with the potato harvest north of the border.

Overall there is estimated to be about 25% of the crop still in the ground. Most growers have left heaviest land till last and 5 acres a day per harvester has been the norm. But conditions have meant bruising has not been a problem, unlike English crops. 

Slow store filling means getting the cold store doors shut and temperature pulled down are the priority for quality. Tuber temperatures going into store have not fallen below 10C, which means curing should have been completed within 7-10 days of lifting.

As always the weather provides us with some real challenges. If it's not too wet then it's too dry.

 

One good thing is that the recent dry spell has helped reduce the spread of bacterial rots, with the main problem now being bruising and how to avoid it. Carrying soil on harvesters is proving difficult at times, if not already doing so can you use a smaller web? Keep the harvester full if you can, even when turning at the row ends.

 

Despite most soils being drier than normal during tuber initiation there are now reports of black dot development on high-risk packing crops. Periods of stress may have physiologically aged the crop, possibly resulting in early senescence of the canopy.

The tail end of Hurricane Katia and heavy showers since have not helped the already slow potato harvest in the east of Scotland. Torrential rain has left all but the freest draining land at field capacity although "above average levels of sunshine for the east of Scotland" are predicted for the next month. So let's hope the forecast is right!

 

Tuber numbers are generally above average. Coupled with little sunshine in the later part of the season, this has meant late burn-off for some seed and ware crops. Desiccation has generally worked well but some indeterminate varieties are sometimes requiring a third application to prevent regrowth.   

 

Waterlogging is the major problem with most fields having some soft rot patches. Boxes from these areas and wet tramlines need to be kept separate. For seed growers, positive ventilation is going to be critical to reduce erwinia bacteria levels and sufficiently dry the crop going into store. Ware growers need to make sure fridges and fans keep air moving during store loading and the front of the fridge is kept full of boxes to prevent short circuiting of air.

 

Oh the joy of growing potatoes! There is always a challenge somewhere. Certainly in the area in which I cover across northern England and into the Scottish Borders there is a huge amount of variability in crops. Generally size is not an issue and it is mainly tuber number which is determining whether a crop is high or low yielding.

 

If anything most crops are on the bold side so making decisions on the timing of burn down will be crucial if oversize is to be prevented. Quality is also extremely variable mainly due to Blackleg, but latterly powdery scab seems to be more prevalent due to the cool and damp conditions in August.

 

Blackleg is likely to be a hot topic for the rest of this year and into next, particularly with the amounts found in ware crops due for storage and the amounts found in seed crops, particularly in parts of the UK where there has been more rainfall.