FINE TUNING blight control by using a new drift retardant can improve efficacy by up to 19%, according to the latest independent trials using Interagro’s Crusade.

Adding the low-cost drift retardant to a fungicide tank mix has also led to improved yields – by an average of 2.2t/ha – which at a price of £200 per tonne, equates to £440/ha improvement in margins.

Costing ‘just a few pounds per ha’ the specialist drift retardant, Crusade, is being launched to the market this summer. 

“The product has been rigorously tested, and its launch follows two years of independent trials conducted by SRUC’s Dr Ruairidh Bain, as well as in-field studies by Eurofins, Agrii and a range of fungicide manufacturers, including market-leader BASF,” said Emma Ralph, from Interagro.

Dr Bain described the launch as ‘exciting’ for the potato industry. That’s because products like this don’t increase the amount of fungicide being applied, rather they provide the industry with a valuable integrated crop management (ICM) option. 

The Crusade trials were conducted in 2014 and 2016 as part of Dr Bain’s potato blight research and carried out as part of SRUC’s extensive field trials at Scottish sites.

The two seasons were very different. Dr Bain said the epidemiology developed fairly gradually in 2014, whilst in 2016 potato crops were challenged early, with blight present in the crop as soon as the Crusade-including sprays were started. 

“We studied Crusade tank-mixed with six different fungicides, four SCs and two WGs. When Crusade at 0.5 l/ha was added to Percos, the results were really quite outstanding,” he explained. 

“For five out of the six fungicides, there were statistically significant improvements and the sixth showed a positive trend.

“What’s most interesting is the consistently positive responses with all fungicides we trialled. We already know that adjuvants can make a real difference to fungicide performance, but most are fungicide specific.

Crusade gives the flexibility both in terms of product compatibility and timing,” he pointed out.

Interagro’s Ms Ralph told The SF that other independent trials concurred with Dr Bain’s findings.

“Crusade has been developed to minimise drift and support full coverage and optimum dose of fungicide to all parts of the crop which we know is so vital to protect against blight,” she said.

“By reducing the number of fine droplets prone to drift and helping the fungicide to spread after application, we get better coverage to the full haulm, with improved penetration into the crop.

“Field observations and grower experience confirm that Crusade also cut drying times for partner fungicides, which brings real practical advantages, namely enabling growers to continue spraying in showery conditions,” she explained. 

“The trials and extensive use on-farm in 2016 also demonstrated impeccable crop safety, even with Shirlan, known to cause phytotoxicity when mixed with mineral oil.

“With current blight strains producing sporangia earlier and in greater numbers than older strains, maximum coverage with fungicide is crucial. 

“Where coverage is not optimal, there tends to be scattered infection across the crop, which moves the risk of tuber infection to the whole crop. 

“Growers understand the principles of effective blight control – the right fungicide choice, at sufficient dose, applied at tight intervals – but we all know that sometimes things don’t go to plan and spray programmes are compromised,” she added. 

Crusade has been proven to improve blight control with all partner fungicides it has been tested with – including Hubble, Percos, Presidium, Electis, Shinkon and Shirlan, plus a range of other partner fungicides in commercial field programmes.

It can be used on all potato crops at a dose rate of 0.25% v/v. At a water volume of 200 l/ha, this equates to 0.5 l/ha – at 300 l/ha, the application rate is 0.75 l/ha. 

Interagro advised that Crusade should added to the water in the sprayer tank before any other products. It is available to purchase now via Agrii dealers.