Potato Review

www.potatoreview.com POTATO REVIEW SEPTEMBER/OCTOBER 2019 45 SEED HEALTH Harvest and grading machinery are also areas of concern for Mr Green and he advises the use of a knapsack sprayer to disinfect all components that come into contact with tubers as regularly as possible and between each eld or seed lot. “It doesn’t have to take long, as it can be done from a static position while machines are running,” he adds. Early harvest Harvest is another area where practices can have a big impact on nal tuber disease levels. Seed should be lifted at the earliest opportunity to avoid the crop sitting in the ground for extended periods or wet conditions at the back end of the season, as both exacerbate all major tuber diseases except dry rot. With damage o ering diseases such as dry rot and gangrene an easy entry into tubers, Yorkshire-based SPUD Agronomy potato specialist John Sarup says completing haulm destruction in good time is also paramount. “Preventing damage at harvest is a particular challenge on stony soils in the Yorkshire Wolds, so focussing on achieving a good skin set will help. It is the rst line of defence,” he said. Correct harvester set up also plays a key role in reducing tuber damage and Mr Jessiman says experienced operators should know how to maximise harvester e ciency while remaining sympathetic to tubers. However, where relatively inexperienced sta are used, adequate training is vital to help limit any nicks and scrapes to skins or internal bruising. Tubers should be adequately cushioned by soil as it comes up the web, any hard falls into boxes broken, aggressive separation avoided, and damage levels monitored on a regular basis to identify problems early. Adjustments can then be made to the machine. “ e crop is in the store for a long period, so if you can get it in as e ciently and as gently as possible, you save a lot of hassles with disease problems later on.” Seed treatments Further to hygiene and reducing damage, broad-spectrum seed treatments such as imazalil (Gavel) can provide a good insurance policy against infection and development of tuber diseases. Mr Jessiman says the decision to apply a seed treatment lies with the grower and whether any problems have been identi ed, but he would advocate a seed treatment in most years if the crop is clean and dry at the point of application. Work carried out by Scotland’s Rural College (SRUC) over a number of years have shown treatments are best applied within 48 hours of harvest, either on the harvester or over a roller table if split grading into store. With the vast majority of Scottish growers harvesting into boxes, most will opt to avoid tipping and handling seed a second time, so will apply using a liquid applicator situated on the harvester’s nal drop or elevator. is should be situated where spray coverage is least likely to be a ected by the wind. From left: SAC Consulting seed production expert Innes Jessiman, Chairman of the NAAC CIPC application group, Nick Green; agronomy potato specialist John Sarup and Nick Badger of Certis all spoke to Potato Review about the importance of store hygiene on seed potatoes. Dry rot on seed tubers. “The crop is in the store for a long period, so if you can get it in as e ciently and as gently as possible, you save a lot of hassles with disease.” ➜