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Potato Science Live focus on blight change implications

Agronomy Issues
Blight trials at Eurofins
Blight trials at Eurofins demonstrated the dramatic effects of strains with reduced sensitivity to fluazinam - providing a clear lesson to growers

The ever moving target of blight races has seen further changes to challenges evolving for growers, according to Syngenta Technical Manager, Michael Tait. He highlighted that monitoring in 2018 involved a relatively low number of samples, from across a limited geographical spread, but still gave some clear indications.

Speaking at Syngenta Potato Science Live, he reported the genotype 36_A2 had increased as a percentage of the total population in this sample. When tested under very low doses of fungicide actives, in trials commissioned by AHDB Potatoes, 36_A2 also developed larger lesions than other genotypes.

Michael Tait

“It’s something to watch but it’s important to remember that these tests were conducted at extremely low doses and there is no evidence of resistance to 36_A2 in any of the actives which were tested,” Michael added.

“It has however reinforced the message around the need for application to get the full dose throughout the canopy, and a tight application interval to maintain an adequate dose on the leaf,” he advised growers and agronomists at Potato Science Live.

He also urged caution where blight fungicide tank mixes could see one active decline quickly on the leaf, which would leave the other potentially exposed to resistance developing.

Blight on stems

However, with the significantly reduced use of fluazinam, there could potentially be a lower incidence of 37_A2 race in the future.

“The experience with blight strain 37_A2 and its reduced sensitivity to fluazinam should be a salutary lesson for growers,” Michael warned. 

“It has absolutely proven the benefit of robust rates and tight spray intervals as well as alternating modes of action, such as Revus, through the programme, rather than blocks of the same product or active group for the 2019 season.”

Potato Science Live logo

This season’s extended series of Syngenta Potato Science Live events gave growers and agronomists an exciting insight into some of the future technologies designed to enhance the efficiency and profitability of potato crop production.

With a range of speakers and specialists from across the industry, Potato Science Live provided a first look at a range of new agronomy opportunities, along with some ideas and practical measures that could be readily implemented this season.


Read more reports from Potato Science Live. Click on the links below:

Syngenta Potato Science looks to clean soil start

Potato Science Live sees Green Headland hits to aphids

Aphid advice to stop virus spread at Potato Science Live