Blight programmes meet challenge of changing clones
The dynamic adaptation of new genotypes of potato blight continues to put pressure on management strategies, warns Syngenta Technical Manager, Michael Tait.
But he believes the work of AHDB and the James Hutton Institute in tracking genotype populations has been instrumental in telegraphing potential problem issues as early as possible.
Monitoring in 2020 confirmed the continued spread of the more aggressive EU_36 across the country, along with greater incidence of EU_37 associated with reduced sensitivity to fluazinam, he reported. It has also picked up further reductions in the proportion of the 13A2 genotype that had been seen to be less susceptible to phenylamides.
“Importantly the work at JHI, to test for any potential reduction in efficacy of the key fungicide groups, has shown continued high levels of control of mandipropamid (Revus) against all the main blight genotypes tested over the past three seasons," he reported.
“It’s confirmation that the strategy of combining and alternating fungicide actives through the programme is working effectively.”
He reported that this has been demonstrated in the Syngenta intrinsic activity trials at Eurofins in 2020. The trial has been uniquely designed as the industries’ only season-long single product programme, under high pressure field conditions, that truly tested performance.
“Results have once again shown that Revus, along with Amphore Plus and Carial Star, also containing mandipropamid, performed exceptionally well, even with inoculation of blight strains including EU_36 for the first time this season.”
Furthermore, for the second year running, the performance of Revus has been optimised with the addition of a drift retardant technology. “Using a drift retardant with Revus is now our recommendation for the 2021 season. It would appear to get more spray into the canopy and onto the leaf, and with the movement of mandipropamid across the leaf wax layer, that’s further enhancing performance.
Get up to date with this season’s agronomy issues from the topic focussed Potato Science Live webinars:
Seed and soil-borne pathogens
PCN and soil pests
Blight management & application
Biostimulants & Quantis
Sustainability & Green Headlands