Potato Review

28 POTATO REVIEW MARCH/APRIL 2020 FARM TRIALS Effective flailing Flailing was also shown to be effective. The length and density of the canopy also altered the ease of cutting of the tops off the plants. Most varieties were cut vertically, but the late- maturing lodged stems were more difficult to do correctly. This is because later-maturing varieties such as Royal are more difficult to flail effectively to an even length, which should be between six and eight inches. “If the crop is leaning over, it can be really hard to cut to the right height. If you cut it too short it can cause tuber damage and there is no stem for the chemistry to hit,” said Graham, adding: “Flailing is already well established within the seed and salad sectors as it is the quickest way to stop tuber growth and desiccate crops. “For other sectors, if the autumn is wet, it can do a lot of damage to the land because of the weight of the tractor and the flail.” Will added: “We used three types, Baselier, Grimme front topper and Scotts, and they all did a good job.” An alternative way when the ground is too wet to hold the weight of the topper and the tractor, is to use a PPO first, then flail afterwards, followed by a second spray, Graham said. The late-maturing Jelly variety, grown for seed, was used for the first of the SPot FarmNorth trials, which was desiccated at full canopy. Maris Piper was given similar treatment, and three weeks later it was all dead. However at that point in August many crops were running out of steam anyway, which explains yields not being higher despite good growing conditions through the majority of the season. The trials at Elveden used the indeterminate maincrop variety Royal, where some stems were 1.80m long at desiccation, making it a difficult crop to desiccate. Other varieties used in this year’s trials include the packing variety Georgina at Dillington and the crisper Titan at Heal Farms. Further data has been collected from two experiments in Scotland by staff from the James Hutton Institute following the protocols set by NIAB CUF. While Reglone’s speed of desiccation was known as its major advantage, overall, four weeks after desiccation there was no statistical difference, but overall the canopy desiccation was slower with Spotlight/Gozai combinations than Reglone (diquat). “Saltex did a good job at 14 days, although efficacy depended on atmospheric conditions. Pelargonic acid (Finalsan) was the slowest acting of the trialled actives.” ➜ “Some non-replicated plot comparisons in October indicated applications of PPOs later in the day reduced performance.” Graham Tomalin