Potato Review

46 POTATO REVIEW SEPTEMBER/OCTOBER 2019 SEED HEALTH Product stewardship While e cient, Nick Badger of Gavel approval holder Certis says one issue when applying tuber treatments on the harvester is that it covers all tubers, including those too large for the seed fraction. Some growers opt to sell these “tops” into ware markets and because neither imazalil or alternative thiabendazole is permitted for use in ware crops, growers can run the risk of rejection or maximum residue limit (MRL) exceedances. “With so many crop protection products already under the regulatory spotlight, it is important to ensure these products don’t inadvertently enter the food chain,” he said. “Where growers are intending to sell tops into the ware market, it is best to gear up to split grade into store and only apply product to the size fractions suitable for seed.” Whichever option is used, Mr Jessiman says regular maintenance and calibration of application equipment is important in achieving optimum product coverage. “For roller tables, you need to ensure you have a constant throughput and the right ow from the nozzles. Also make sure you ll the table and get the tubers rolling three or four times during the spraying process. You don’t want them sliding along the table,” he adds. Optimise storage Finally, once boxed and loaded into store, crops should be dried and cured with positive ventilation, ensuring there is not a signi cant gap between air and tuber temperatures. is can cause condensation and increase the risk of disease spreading, particularly silver scurf. Store temperature should then be brought down to about 4C, either with ambient air if cool enough, or using a fridge, and the crop monitored regularly during the rst 2-3 weeks of storage. Monitoring methods include washing and visually assessing seed lots, sending samples for laboratory testing or placing tubers in a hotbox to encourage expression of any disease present. Mr Jessiman adds that where possible post-storage, seed should be loaded into 1.25t bulk bags just in time for haulage to customers where possible to avoid heat and condensation developing in the centre. Where storage in bags is enforced, avoid stacking them too close together and place on pallets to encourage air ow around the bags. “Once delivered, encourage customers to empty seed straight into boxes and ventilate as soon as possible,” he said. SUMMARY MINIMISING FUNGAL DISEASES IN POTATO SEED • Good quality seed free from fungal diseases is vital for the overall health of the British potato crop. • Pathogens silver scurf, dry rot, gangrene and skin spot always a risk, with severity depending on seasonal conditions. • Good skin set, early harvest and minimal damage during harvest/ handling process key to reducing risk of tuber disease ingress. • oroughly clean and disinfect all stores with peroxyacetic acid ahead of loading new crop. • Regularly clean and disinfect grading/harvesting equipment during operation and always between di erent seed lots. • Seed treatments such as imazalil applied within 48 hours of harvest o er the best control of fungal pathogens. • Regular maintenance and calibration of seed treatment applicators is vital for optimum tuber coverage. • Do not apply seed treatments to oversize tubers destined for the ware market, as MRL exceedances can lead to rejections. • Do not store in poly bulk bags for extended periods and encourage customers to decant into boxes immediately on delivery. Move up in the world with ● Extendo 600 & 900 - Extending elevators ● Euro X - Standard elevators ● Inter-Store 600 & 900 - Single and double conveyors For further information on the Swift-Lift range contact your local Dealer, or Paul Johnson at: Terry Johnson Ltd Cranmore Lane, Holbeach, Lincs. PE12 7HT Tel: 01406 422286 Fax: 01406 426356 Elevators & Conveyors T D J High output, gentle handling and an excellent reputation for reliability and quality of manufacture make Swift-Lift elevators and conveyors your natural first choice TDJ 2/16/05 12:36 PM Page 1 STAY IN TOUCH ON THE GO! VISIT US AT: WWW.POTATOREVIEW.COM