Growers warned over black dot

Wet soils are posing a high risk of black dot on potatoes being harvested over the coming weeks, Dr Jeff Peters of Central Science Laboratory has forecast.

Peters told growers at the East Anglian Potato Event - held near Aylsham on 5 September and organised by Greenvale AP, Frontier Agriculture and Syngenta Crop Protection UK - that the saturated soils have been highly conducive to disease development, and every week's delay in harvesting with the wet conditions increases the risk.

Growers, he said, should be deciding now when to desiccate crops to minimise the risk of the skin disease reaching levels where retailers may start to penalise the quality of pre-pack samples.

Trials, funded by the Potato Council and the Scottish Government, have shown that maincrop varieties that are in the ground for more than 130 days from 50 per cent crop emergence to harvest have a significantly higher level of disease infection.

For second earlies, the risk increases after 120 days.

"If growers can lift before this time, then skin quality can be maintained with good storage," Peters advised. "Where there is a risk of black dot, tubers should be cooled to 3.5 degsC in store as quickly as possible.

"Typically, infection may be at levels growers would not even see at harvest, but will be clearly visible as the areas of skin with microsclerotia darken up over several weeks, or when tubers are brought out of cold store for packing."

He added that, although trials have shown no advantage of ventilation for black dot control, drying tubers will be highly important to minimise other storage rots this season.

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

What does the 25-year plan mean for growers?

What does the 25-year plan mean for growers?

Published on 11 January, the Government's long-awaited 'A Green Future: Our 25 Year Plan to Improve the Environment' brings together a number of policy strands into a single framework that will impact many sectors, not least fresh produce, over the coming decades.

What will 'embracing change' mean for horticulture?

What will 'embracing change' mean for horticulture?

At the Oxford Farming Conference, whose theme was "embracing change", Defra secretary Michael Gove expanded on what a post-Brexit UK agriculture and land-use policy will look like and how it will impact farmers and growers.

Can growers see off the looming labour crisis by boosting efficiency?

Can growers see off the looming labour crisis by boosting efficiency?

Concern over the availability of seasonal labour to the fresh-produce industry has never been greater.