Potato Review

www.potatoreview.com POTATO REVIEW MARCH/APRIL 2023 17 NEMATICIDES “Machines should be calibrated before the start of the season to ensure that all outlets are applying evenly and that the overall rate being applied is correct,” he said. “Daily checks should also be carried out to ensure that pipework is connected, the hopper bungs are in place and the hopper lids are secure.” He reminded growers that professional calibration should be carried out by a National Sprayer Testing Scheme-quali ed engineer at least once every two years. Manage the application process e way the granular nematicide is applied should be carefully controlled to achieve accurate, even application, and thereby remove the risk of e ects to wildlife. “In order to prevent exposure of granules to wildlife it is important to apply nematicides in a single pass, and headlands should be cultivated to ensure no granules are left on the surface,” Simon said. “ e ow of granules needs to be shut o at least three metres before the end of each row end. Make sure you consider the delay between shutting o the ow and the last granules leaving the outlet, as each machine is di erent.” Small spillages should be buried immediately, while larger spillages should be gathered into the original container and the manufacturer contacted for guidance on safe disposal. Perform wildlife checks Any adverse e ects on wildlife should be monitored by carrying out eld checks between 12 and 24 hours after the application of granular nematicides. “Areas requiring the greatest attention are where machines are stopped and started, such as obstacles in the elds and false headlands,” Simon said. “So far, no impacts on wildlife have been observed, but it’s vital these checks are recorded so a paper trail can be provided for Red Tractor inspections and as part of the NSP Best Practice Protocol.” Grower case study RS BRIGHT Ltd grows 12,000 tonnes of processing potatoes in Herefordshire. Alongside its two agronomists Andrew Goodinson, from Hutchinsons and Harry James from Prochem, the grower takes a proactive approach to managing PCN to help ensure potatoes remain a viable part of the farm business. “We use a combination of long crop rotations, cover cropping, historic pest levels, good husbandry and hygiene, soil testing, and control with a granular nematicide where needed to help to reduce the risk of PCN infestations building up in soil,” explains SamBright of RS Bright Ltd. “Potatoes are normally grown one in every six years but we will skip a rotation and allow 10 years plus if required,” he adds. “ e rotation includes winter wheat, oilseed rape, a two-year grass ley, wheat and potatoes. PCN-busting cover crops, such as mustard, are used to help target the pest.” Sam explains that the business uses soil testing to understand the population level of PCN and tends to use historic pest levels to inform the testing strategy. “ is means that we generally test any elds where we know the risk has been high previously, which is most often rented land where too many potatoes have been grown historically,” he says. “If high levels of PCN are present, we manage this by applying a granular nematicide in a very targeted way. We recognise the need to maintain availability of granular nematicides to potato growers long-term, and therefore take stewardship extremely seriously.” To achieve an even application, they always apply nematicides in a single pass. “We use a rotary tiller to incorporate the product into the destoned bed ahead of the planter, mixing the granules to a depth of 15cm. e machine shuts o the owwith enough room for all granules to have passed through the system before the row end. is ensures all chemical is incorporated into the soil before reaching the headland.” “The flow of granules needs to be shut o at least three metres before the end of each row end.” Simon Alexander, NSP Simon Alexander, potato agronomist and working group member of the Nematicide Stewardship Programme (NSP), says 65% of land used for growing potatoes is infested with PCN. PCN (potato cyst nematode) patches in a crop of potatoes. Photo: Blackthorn Arable