Potato growers are being urged to prepare now for changes in the potato seed treatment line-up this spring, as product choices and application options have narrowed.
Last autumn, Bayer announced it was pulling sales of its powder treatment Monceren (pencycuron) that was widely used for Rhizoctonia control, citing “uncertainty over its regulatory future” as the key reason.
This will force a big change in application practice, as it was the only powder treatment still allowed to be hand sprinkled on seed tubers, either in the planter hopper, potato boxes or chitting trays.
About 30% of powder seed treatment was still manually applied in 2019 and these growers will have to reconsider how they treat seed, according to independent potato specialist Andy Alexander.
One alternative is to order seed for ware crops pre-treated with a liquid treatment of either RhiNo (flutolanil) or Maxim (fludioxonil) or treat the seed on arrival. Only RhiNo can be used on seed for seed crops.
“It is going to be a completely different ballgame for some growers and my preference is to switch to a liquid treatment, either applied by the seed supplier or a mobile contractor.
“It’s also possible to invest in the liquid application equipment for the grading line and do it in-house,” explains Mr Alexander, who advises potato growers across East Anglia.
Those wanting to maintain the flexibility of treating at planting will need to choose an alternative powder product – either RhiNo DS (flutolanil) or Emesto Prime DS (penflufen) – and fit an on-planter powder applicator, as they cannot be applied manually.
“Some businesses will stick with powders and having to move to an on-planter applicator is a positive step, both from an operator and environmental safety perspective,” adds Mr Alexander.
On-planter powder applicators are available from Techneat and Team Sprayers.
For Techneat’s Powder Pro system, re-calibration is required for any change in product formulation to ensure the correct rate is applied.
The Team Sprayers powder applicator with Digimon control box calibrates automatically within +/- 5% of the set output, allows output to be adjusted from 0.6kg/tonne upwards and can be fitted to all makes of cup or belt planter.
To move on to RhiNo DS, users can select the Monceren setting and just change the application rate to 2kg/tonne; the dose recommended by manufacturer Certis for controlling black scurf and stem and stolon canker caused by Rhizoctonia solani.