Seed suppliers are being encouraged to protect their high-quality product from storage diseases at first grading following a wet harvest last year.
To prevent disease development on seed in the first place, an application of tuber fungicide treatment Gavel (imazalil) could be appropriate, says merchant Frontier.
Tuber pathogens that develop in seed from harvest to delivery include dry rot, gangrene, silver scurf and skin spot.
Once established, they can be difficult to eradicate, significantly affect seed quality and cause problems in following crops.
Darren Wonnacott, who works at Frontier, explains there are three phases where Gavel can be applied.
This includes harvest or as tubers are loaded into store; during storage, usually at first grading; and finally when the crop leaves store for delivery.
Mr Wonnacott suggests last year’s wet harvest in some seed producing areas will have increased the risk of diseases, particularly skin spot and silver scurf.
He’s also seen mummified seed tubers in some stocks, where they were infected with disease and dried out in cold storage – these are now a source of inoculum.
“There’s the potential for any inoculum to spread so my advice would be to apply Gavel where it hasn’t already been applied in that phase two window," he says.
“Seed supplies are tight this year and values are very high, so it makes any investment in a treatment relatively cheap, particularly as a small problem now can turn into a significant one before delivery. It’s a no brainer for me."
Skin spot is of particular concern this winter in high-risk susceptible varieties like King Edward and Rooster because of conditions during lifting, Mr Wonnacott explains.
In these high-risk cases, he suggests a combination of Gavel and Storite Excel (thiabendazole) to bolster protection against skin spot, a pathogen which causes poor and uneven emergence in the following crop.
To apply storage fungicides like Gavel evenly across seed tubers, Mr Wonnacott advises using a roller table applicator with a rotating hollow cone nozzle and air assisted hooded canopy.
He says: “Always make sure your equipment is set up right and has been serviced and calibrated before use, as it’ll ensure you get the most out of the treatments and keep seed in the best condition for planting.”
