Arable News

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Early action vital to beat potential blight epidemic

Potatocrops are at very high risk from a serious blight epidemic this season andgrowers will need to begin control programmes early to keep the disease at bay,leading agronomy firm Hutchinsons warns.

The mild,wet winter and spring has created ideal conditions for the development ofblight inoculum across the UK, says the firms Darryl Shailes, who says that someblight cases have already been confirmed by the Potato Councils Fight AgainstBlight monitoring service (

We haventhad a harsh winter to knock back the inoculum or reduce the number ofvolunteers and with the current mild temperatures and frequent rain we are onfor a pretty serious blight epidemic in all crops this year.

Blight hasalready been confirmed in a potato dump in East Anglia and there has beenblight recorded in glasshouse crops in Lincolnshire as early as anyone canrecall, he says.

Thesituation is equally concerning further north in Scotland where Ayrshire-basedHutchinsons agronomist Cameron Ferguson says exceptionally wet weather andtemperatures well into the high-teens recently have increased blight pressure.

There havealready been two blight warnings by the end of May and growers will have to beextremely vigilant for blight. The pressure has been eased slightly by the factthat maincrop planting was delayed due to the wet weather, but nearlyeverything is now in the ground and is getting away well in the warm, wetsoils.

Werecertainly going to be starting weekly blight control sprays from late May/early June in many cases, which will be a lot earlier than many growers areused to. Blight sprays normally start when the crops at the rosette stage.

Robust action needed

Potatocrops grown under plastic are at particular risk from early blight and may alsoact as a source of infection for neighbouring crops when the plastic is removedand blight spores are released, says Mr Shailes.

The hugenumber of potato volunteers in crops elsewhere, along with outgrade piles arealso key sources of infection that growers should remove at the earliestopportunity, he adds. Theres really no excuse for allowing blight in throughpotato dumps.

In terms ofblight fungicides, Mr Shailes advises growers to begin blight spraying as soonas crops emerge where the disease is an imminent threat.

Dontthink that just because the plants not very big then blight wont be aproblem. Blight that is allowed to infect young plants can be extremelydamaging and means that youll be left chasing it all season.

Going inwith a robust fungicide strategy from day one avoids getting into thissituation and means there may be the opportunity to cut back later in theseason if conditions arent as conducive to blight development.

He advisesgrowers to choose products that offer good contact/ residual control as well asanti-sporulant activity, such as those based on fluopicolid + propamocarb ordimethomorph. Growers using products based on mandipropamid or cyazofamid aloneshould look to include an additional active with anti-sporulant activity, hesays.

Rates forall blight fungicides should be kept at the full label recommendation, henotes. Never reduce rates of blight fungicides, especially when pressure ishigh.

Hutchinsonsarea business manager for the north east, Geoff Mason, suggests that growersmay need to consider securing fungicide supplies early, as the high diseasepressure will put significant demand on supplies of key products.

After theindustry suffering huge problems with the lack of products for use in arablecrops, it may be prudent for growers to get their choice of products orderedquickly to guarantee supply this season.

Watch slug risk too

Alongsideblight, Mr Ferguson also warns growers to be extra vigilant for slugs thisseason, as the mild, wet weather has resulted in unprecedented numbers.

Slugdamage to tubers could be a major issue later in the year unless the weatherturns exceptionally dry this summer. Slugs have continued breeding throughoutthe winter and vigilance will be paramount.

Hutchinsonsadds that it is proud to sponsor a new technical event for potato growers inScotland next month.

The East ofScotland Potato Event is a free event organised by the Potato Council that isfocussing on the challenges and control strategies for Potato Cyst Nematode(PCN).

It willhighlight how growers can work together to address PCN issues, examine the roleof testing and bio-fumigants, plus Hutchinsons potato specialist Darryl Shaileswill explain the chemical control options and how planning and implementing acontrol programme can reduce PCN levels and protect crops.

Workingwith Claire Hodge of the Potato Council, we are delighted to be sponsoring thisnew event, which we are sure growers will find to be of benefit, commentsGeoff Mason of Hutchinsons.

The eventwill be held between 14:30-19:30 hours on Tuesday 15 July 2014 at Newmill OfBalgavies Farm, Forfar, Angus, DD8 2SF.

For furtherinformation and to register, go to:


  • Written by: Farmers Guide
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