Syngenta Crop Protection UK Ltd
Act now to know soil-borne disease
09/02/2010
Potato growers should be looking at soil testing for Black Dot now on fields destined for potatoes this spring, advises John Purslow of JP Agronomy. Particularly for growers of packing varieties on rented ground where they don’t know the history, he adds.
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New Black Dot soil tests can give growers useful guidance on disease risk and treatment options.
Mr Purslow believes soil testing can give a good indication for targeting Amistar applications. “Although many growers on sandier soils tell me they’ll treat anyway. Amistar at 3 litres/ha in-furrow at planting should do the trick.” This application also offers effective control of Rhizoctonia, he notes.
“Packing growers will definitely consider Amistar, and an increasing number of processing growers too, given its beneficial effect on fry colour and yield.”
Simon Alexander of SA Consulting agrees growers should be assessing disease risk on fields destined for the crop. “Field history is a good guide. If you’re renting, ask the landlord,” he says.
“Also consider the number of volunteers, and then you can assess the need to treat for Rhizoctonia on susceptible crops,” he adds.
Assess risk now to decide on Amistar treatments for Rhizoctonia susceptible crops, advises Simon Alexander (below)
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Potato crops were suffering from a higher level of skin diseases going into store last harvest, warns Simon Bowen
Skin infection threatens store quality
After last season’s conditions any packing crops still in store should be checked very carefully for skin diseases developing, advises Simon Bowen of potato supplier Solanum. “A lot of crops went into store with more skin disease than usual, as growers delayed lifting due to dry soils, especially in eastern counties,” he notes. “That inevitably encouraged the problem.”
Growers should take washed samples to check levels, particularly of Silver Scurf and Black Dot. “Many growers tend not to look now, but we recommend it,” says Mr Bowen. Catching these diseases early can give growers time to load them out and still achieve a packing premium – and that could amount to £50-100/t, he says.
Processing crop stores should also be checked closely after the cold period to ensure temperatures have not slipped. “Some stores may not have been tested by such hard weather before,” he notes. If unsure, growers should conduct a fry test to see whether there might be a problem with fry colour in potatoes due to be sold.
Amistar seedbed treatments this spring can minimise skin diseases at harvest and improve potential for long-term storage – along with quality premiums at pack-out. Processing crop growers are also recognizing the value of Amistar for Rhizoctonia control to give higher tuber yields, with more consistent size and maturity for better fry colour; better skin finish which can also reduce processing costs and waste.
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