John Mason is an Agrii agronomist based in Inverness-shire in Scotland, and advises on about 150 acres of potatoes. As with all products he recommends, John looks for ways to maximise efficacy, and with blight control this is absolutely crucial. John has been recommending Crusade for the last three years, and with the flexibility and benefits Crusade offers, will be recommending Crusade with all fungicides throughout the blight programme this year.

“The windows for blight spraying in Inverness-shire mean spray intervals either have to tighten because rain is coming or where a seven-day interval is maintained, there’s a risk rain soon after will spoil the programme,” he explains.

John looks after potatoes being grown for the local ware market, as well as crops being grown for first-generation and pre-basic seed. As with all products he recommends, he looks for ways to maximise efficacy and with blight control this is absolutely crucial.

His blight programmes begin early doors, typically starting with Lieto (zoxamide+ cymoxanil) or Profilux (cymoxanil+ mancozeb) at the rosette stage, as soon as there’s a target big enough to hit.

“Then I’ll follow with Versilus (benthiavalicarb) plus mancozeb before bringing in products with systemic activity such as Axidor (cymoxanil+ propamocarb) and Zorvec Enicade (oxathiapiprolin), alternating modes of action through the rapid and stable canopy stages for resistance management.”

Typically John achieves this by using products from the different fungicide groups – carboxylic acid amides (CAA), which include Dimix (dimethomorph), Versilus; Lieto from the benzamide group and Percos (ametoctradin+ dimethomorph), which contains actives from the Quinone outside Inhibitor, stigmatellin binding type (QoSI) and CAA group.

He makes strategic use of the Quinone inside Inhibitors (QiI), e.g. Shinkon (amisulbrom), protecting them by mixing with appropriate partner products. The challenge is making sure the actives with activity on tuber blight are still available for use at the end of the season.

Having recommended Crusade for the past three seasons, John is going a step further and plans to apply all blight sprays with the drift retardant this year.

I had an issue where I didn’t put Crusade in the mix and now regard it as more than the drift retardant, but also as a weather safener and an aid to canopy penetration.

John Mason, Agronomist, Agrii

“Where it’s applied with a blight spray the potato leaves act like a car that’s been polished and any water that lands on them beads. That means the canopy dries really quickly and doesn’t harbour the humid conditions which blight thrives on.”

For some people there’s still a stigma surrounding the use of drift retardants but Crusade has been put through independent and Agrii trials which was how John felt confident to try the product.

There’s a real benefit from using it which growers are noticing and none more so than one of John’s client, Don Mowat, who farms on the North coast of Scotland near John o’ Groats, looking out over Orkney.

“Don is exposed to the weather from the North and East coasts, so wind is a real problem for him. He often has to spray his potatoes in less than ideal conditions which means a drift retardant is essential,” explains John.

“Previously he’d been using Headland Guard but moved to Crusade last season. The first time he used it, Don rang me to say he could hardly see the spray moving which is testament to its phenomenal drift retardant properties under really challenging conditions.”