DO NOT miss the opportunity to control volunteer potatoes in cereals and sugar beet this spring, the British Potato Council (BPC) has warned.

Volunteer potatoes can serve as a primary source of inoculum if the tubers are infected with blight, said BPC’s Mark Prentice.

“And even if they are free from blight, they have unprotected foliage and are at risk of picking up spores and acting as a secondary host.”

That means growers should be acting now, said Reuben Morris, technical manager of Cropwise.

“The volunteers will tend to be evenly spread around the field, but will be emerging from different depths, and so coming up at different times.

“In sugar beet growers should be planning to include Shield (clopyralid) + ethofumesate + Debut (triflusulfuron-methyl) to be applied once the first flush of potato volunteers reach six inches tall.

The main treatment for cereals is fluroxypyr at 0.75litres/ha plus a sulfonylurea based on metsulfuron-methyl at full rate, said Dr Morris. “The cut off timing is GS39 for the sulfonyurea component.”

Treating in cereals at either T1 or T2 will help prevent the spread of blight, but if the timing is missed or unsuccessful then pre-harvest roundup (glyphosate) at 4.0litres/ha will give good kill of the daughter tubers.

But, growers will have missed the opportunity to prevent the spread of blight, he added.

A factsheet outlining the importance of controlling volunteer potatoes is available from the BPC at www.potato.org.co.uk.