Potato Review

58 POTATO REVIEW NOVEMBER 2021 ROLLER TABLE TREATMENT Seed grower recommends investing Perthshire-base seed producer Alexander Bayne & Sons made a big step forward in tuber treatment application quality following investment in the latest kit, including a direct chemical injection system. The business grows about 160ha of potatoes, half of which is seed for the UK market, and includes varieties such as Maris Piper, Maris Peer, Saxon and Rooster. Partner Sandy Bayne says the farm previously used a spinning disc applicator over a roller table, but recognised it wasn’t the most accurate means of delivering seed treatment products. In addition, label guidance on increasingly popular products like Maxim also stipulated that low volume hydraulic nozzles must be used during application. After using a Frontier contractor for short time, he soon wanted flexibility to treat in-house so he invested in a new Tong roller table and Team CTC 2 air treatment canopy with rotating nozzles as a replacement, which research has shown to improve tuber coverage by 20-30%. This is serviced by a Storemaster pump and clean water hopper, with an additional four-hopper direct injection system that delivers the exact amount of desired chemical into the pressurised line. Completing the line is a Tong UniFill, which can fill both big bags and boxes with treated seed, depending on customer requirements. Sandy, who often operates the treatment line himself, says it has been “a revelation”. Bespoke system The entire application system was designed and assembled by Frontier application expert Darren Wonnacott to fit at the end of the farm’s grading line, separated from the ware line to avoid contamination. Seed grading is typically carried out from end of November onwards and orders are increasingly requested with seed treatment, or a combination of treatments, by the customer. Sandy says he hasn’t seen an increase in storage disease incidence on farm, as it has good quality cold storage at its disposal. This means seed crops are harvested into boxes and quickly dried, cured and cooled to reduce disease progression from the get-go. However, he says ware customers are becoming much more aware of potential problems and opting for more specialised seed treatments than ever before. “A lot of the basic orders will request Gavel Don’t let poor store hygiene trigger disease outbreaks Applying liquid fungicides to potato seed will help to reduce the impact of storage diseases, but results can be compromised if good store and grading line hygiene practices are not followed. Certis provides comprehensive guidance on getting the most out of seed tuber treatments on its Tubercare website, with a focus on accurate and timely application of products like Gavel and Rhino. But the firm’s technical specialist Harry Raley says that handling and storing seed in a dirty environment can undo the good work and result in infection making its way into tubers and causing losses. “It’s one thing applying the products properly, but without all the other elements of an integrated control strategy, it can quickly fall apart. The dust and spoil in and around stores and grading sheds can carry a high level of disease spores, particularly silver scurf and fusarium, which causes dry rot,” he said. While harvest and moving crops into store will be over by the time of publication, Harry reminds growers of the importance of lifting seed crops as clean as possible to minimise infected soil entering buildings. Stores, grading areas and boxes should also have been disinfected with a peracetic acid product like Jet 5, either with a pressure washer or a fog, before grading and storing. Ozone can also be used to good effect, with ozone generators left in sealed stores for two to three days is a good way of killing any potato pathogens lurking in buildings or empty boxes. Independent expert David Turner agrees that hygiene is vital and says the process doesn’t stop at infrastructure cleaning, with growers advised to keep on top of cleaning around the grading line, as seed is being processed. Ideally, all lines should be disinfected between seed lots, particularly when a problem seed lot with visible signs of disease passes down the line. “Dust should be kept to a minimum and an industrial hoover is preferable to a broom, which kicks up dust that settles on any exposed tubers,” he said. To the same end, areas where forklifts are moving should be kept as clean as possible and disinfectant mats used to clean wheels as the kit moves through entrances and exits. Harry adds that many buildings on potato farms have partition curtains, which were primarily installed for temperature control in part filled stores. “These can also be useful to reduce the movement of dust when graders and forklifts are working close to seed that could be susceptible to infection.” Next time… In the third and final article of the series in the January issue of Potato Review, we will offer advice on how best to treat seed as it comes out of store, with a focus on Rhizoctonia control to help maximise marketable yield in its progeny. as a minimum, but we also have customers that want Gavel and Storite Excel together if they are concerned about skin spot. We can now apply the two without actually mixing chemical together and couldn’t do that without the new equipment.” Alongside Gavel and Storite Excel, the other two of four chemical hoppers contain Maxim and Rhino, with these pre-planting products primarily targeting Rhizoctonia added where necessary. “The system is very low maintenance and with no mixing, we don’t have any part tanks left overnight. Simply by turning a couple of taps, we can flush the pump and nozzles through with clean water each night.” Overall, the treatment system has been well worth the circa £17,000 investment: “I would now say it’s essential to the business, as we could never have anticipated so many requests for seed treatments as we currently get,” said Sandy. This four hopper direct injection system allows grower Sandy Bayne to cleanly and easily switch between seed tuber fungicide treatments during grading.