South Yardley Allotments Society
Allotment sites in Acocks Green and South Yardley


Controlling Common Scab in Potatoes 
 


Common scab is caused by Streptomyces scabies a pathogenic micro-organism that and cause rough, scabby patches. Scabs appear during summer and persist on harvested tubers throughout storage.
Common scab is most serious on potatoes, but also affects beetroot, radishes, swedes and turnips. Common scab is worse when soil conditions are dry when tubers form..


Non-chemical control

To control common scab, do not allow the soil to become dry during tuber development. Raise organic matter levels to improve water retention. Water the developing crop if necessary, starting two to three weeks after plants emerge and continuing for about four weeks and applying 20 litres per sq m (4 gallons per sq yd) every 4 days in dry weather.
• Unfortunately, common scab is worse on alkaline soil, so liming the soil to prevent club root of brassicas will predispose to common scab in potatoes. Apply lime after the potato course of the rotation
• Choose resistant cultivars. ‘Accent’, ‘Arran Pilot’, ‘Juliette’, ‘Golden Wonder’, ‘King Edward’, ‘Pentland Crown’ and ‘Pentland Javelin’ show some resistance to common scab

Chemical control

There are no chemical controls available to gardeners for this disease.




 

 







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