Potato Review

30 POTATO REVIEW MARCH/APRIL 2021 POTATO SCIENCE LIVE matter from the deep rooting. e greenmaterial nutrient recycling was analysed at up to 106 kg/ha of N; 33 kg/ha of P and 172 kg/ha of K. New results on the project from the GWCT, looking at GreenHeadlandmix sown on waterlogged headlands around cereal elds left damaged and unplanted after the disastrous autumn campaign of 2019, had shown 50%of soil mineral Nhad been successfully captured in plant biomass, she reported. “ e Green Headland seed mixes available through the initiative have been selected to be easy to establish and maintain alongside the growing crop,” Belinda said. “ e mixed depth of rooting from di erent species improves rainwater penetration to avoid run-o , whilst helping with the soil structure that will return the eld margin in a better state, compared to uncropped headlands.” e standardmix contains oil radish, phacelia, common vetch, buckwheat and berseemclover. A non-brassica option replaces the oil radish with linseed and crimson clover. Bothmixes were created and supplied by Kings Crops and available to growers at a subsidised cost through the Syngenta initiative. Whilst the project, instigated in collaboration with ASDA, initially sought the sustainable protection of soils and soil health, Belinda highlighted it has also contributed to the enrichment of habitats for farmbiodiversity. Intensive monitoring of the margins has shown the Green Headlands are the preferred habitat for pollinators and many bene cial predators, such as hover ies and lacewings, compared to grass margins that are favoured by spiders and ground beetles. “Research has shown there is potential for the Green Headlands to o er a net gain in reducing pest and virus disease issues in the crop, as part of an Integrated Pest Management strategy,” she said. “Further work for the coming seasons will investigate how that could be best incorporated within the viability of crop production and the emerging details of the new Sustainable Farming Initiative.” Integrated controls for PCN management WITH just one remaining approved granular nematicide for PCN control inmaincrop potatoes, getting the best fromsoil pest IPMprogrammes aremore important than ever for long term management, Michael Tait said. at includes extending rotational breaks as far as practicable and the e ective control of volunteers and host weeds between crops, he urged. Speaking at the Potato Science Live events, he highlighted experience with G. rostochiensis has shown good results can be achievedwith growing resistant varieties, but more suitable cultivars are now required to tackle G. pallida. “Using Nemathorin in combinationwith cultural measures gives the best chance to both protect yields andminimise the impact of PCNmultiplication,” he advised. “Managing PCN populations even at low egg counts will be essential for sustainable future production. Michael reminded growers that Nemathorin has aminimal interval of at least 17 weeks from application to desiccation or harvest. “Whilst that harvest interval does preclude its use on short season crops, it is in place because of the persistence of the product that makes it so e ective for PCN control inmaincrop potatoes.” He reported a series of trials overmany seasons and soil types that has shown it is the best option to optimise yieldprotection in longer season crops. With the need for ongoing proactive nematicide product stewardship, Michael recommends growers and agronomists should positively check and record there have been no adverse e ects onwildlife following application. Whilst there have been no recorded incidences over all the years with Nemathorin use, it is important to collect and store the evidence of no e ects, should its future be challenged, he recommended. Wireworm challenge WIREWORMhas been a recurring issue for many potato growers over recent seasons, possibly as a result of changing climatic conditions for pests, along the withdrawal of Mocap (ethoprophos) and neonicotinoid seed treatments that also had an e ect through the rotation. at has seen a surge in interest inNemathorin as growers seek to reduce the e ects of wireworm damage to tubers. Furthermore, Syngenta Insecticides Technical Manager, DrMax Newbert, outlined proposals for a granular formulation of lambda-cyhalothrin that trials have shown could o er better results. e product is currently in development across a number of European countries and in submission for a UK registration. Research will also investigate optimising in-furrow application techniques to achieve an even distribution of bait points surrounding tubers. e product is speci cally targeted at wireworm in potatoes and maize. PCN cycts on potato roots Green Headland mix alongside potatoes