Potato Review

www.potatoreview.com POTATO REVIEW MARCH/APRIL 2020 11 CUPGRA 2019 CONFERENCE 2019 was a di cult year for many UK growers, and the capacity to recover will be crucial, according to thought-leaders gathered at the CUPGRA 2019 conference. Alarm bells in Germany e withdrawal of CIPC is likely to produce a ‘sprouting mess’ in Germany, according to Dutch independent potato consultant Luit Scholtens of Potato Advice Holland. Working mainly in Germany with potato growers associated to the grower group EZG-Ankum, he has more than 25 years’ experience in crisping and French-fry varieties. Changes in storage temperature, variety choice and dormancy length are the rst places to explore when considering how to best store potatoes in the future, said the agronomist. inking ‘outside the box’ may also help ameliorate the extra expense growers will have to face. For example, by assessing stores for suitability for long-term storages and working as a group, growers with varieties suitable for long-term storage could share space in suitable stores, he suggested. e same could be done with stores which are more suited to medium-term stores. One of the big problems he sees for the German potato growers is that the speed of change in crop protection products is too high for conservative potato growers. Approximately 80%were using liquid CIPC in their potato stores, as it was an easy and e ective means of sprout control, with a single application being made on loading to store. In addition, the price of the new products is high so willingness to adopt and use themwill be low, he warned. “Already when we advise growers to apply CIPC because the tubers have the eyes moving, they say they applied it just a fortnight ago. ey will now try even more to delay treatment, which could lead to a catastrophe.” Mr Scholtens also highlighted the dearth of experience with the new sprout suppressants, which he has been testing for just two seasons. Because most of the growers chose to use liquid CIPC , unlike France, the Netherlands and the UK, there are few companies with expertise in gassing stores, he said. He said there is widespread concern about exceeding maximum residue limits (MRLs), as it could result in losing markets. Protocols are being developed for cleaning stores and advising people how to get the best results. In the short term, he recommended using the still-permitted sprout suppressant maleic hydrazide (MH) with refrigeration to keep tubers dormant but advised purchasing early as demand for the product may be high. Variety choice can also make a di erence as some have longer dormancy, such as Markies, making themmore suitable for long term storage while other varieties, such as Lady Clare, can cope with lower temperatures. “We have stored seed potatoes with temperatures as low as 5 °C, and, at least last season, they fried without creating higher sugar levels,” he said. “If you keep temperatures down, early in the season, it gives you time to decide in which store you want to apply one of the newer sprout suppressants later on. is time is needed in order to make the right decisions and can help you keep down the cost of using the new chemicals.” Sprout suppressant products currently approved for use in stores include 1, 4 Sight and spearmint andMr Scholtens and his team have been undertaking trials evaluating the di erent alternatives to CIPC. He believes ethylene could be a useful product, and there are a number of trials underway across Europe, particularly in the Netherlands and Belgium. In Germany it is not yet allowed. Store size is also likely to impact on sprout suppression e ciency because of di erent sprouting patterns, making di culties to decide when to apply what chemical. “If you go when the rst ones start to peep, it can work out very expensive.” One of the bene ts of spearmint (BioxM) is greater exibility on timing as it can be applied after sprouting, as high doses can burn them o and restore dormancy. Sprouting

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