Potato Review

www.potatoreview.com POTATO REVIEW SEPTEMBER/OCTOBER 2021 21 SEED CARE NEXT TIME… When justified by a risk assessment, fungicide treatments will do a good job, but good application and store hygiene are vital in maximising efficacy. In the second of three articles in November’s Potato Review , we will take a look at best practice roller table use and store hygiene practices to ensure seed remains in top condition before delivery to your customer. said the restrictions on potato seed treatment labels are now having a detrimental impact on seed health. Storite Super contained both imazalil and thiabendazole and offered a one can solution that was cleared for use on ware, until it was withdrawn about five years ago. This meant that growers could treat at harvest, safe in the knowledge that any oversize tubers graded out of the seed fractions would provide a reasonable economic return. They now have the two actives in separate products, both of which can only be used on seed. Darren said this has lead to more growers using no seed treatment at all, or using one product or the other, rather than mixing the two. This is because it is more costly than Storite Super was and there are compatibility issues with mixing straight products Storite Excel and Gavel. Increased disease The survey showed 15% didn’t use a treatment at all and this is one factor leading to higher disease incidence. “We are starting to see more dry rot and gangrene and that’s resulting in losses for both the seed grower and the ware growers later on.” He believes a change in mindset and a move away from treatment at harvest are “Certain thin-skinned varieties are prone to dry rot, so can they be harvested differently to allow a treatment in store? That is a potential starting point.” needed to better control storage diseases, with the best “window of opportunity” being at the point of first grading. The ideal is split grading into store, but he acknowledges that additional handling potentially increases the risk of damage and disease ingress, putting growers off and they also have the practicalities of farm capacity and logistics to consider. “You need to be able to run a digging team to harvest into bulk trailers and a grading team at the same time, but most ware growers do it, so why can’t we with seed?” A disease risk assessment could be a way of ensuring not every seed lot has to be treated, easing the need for a wholesale change in harvest and handling systems, he adds. “Certain thin-skinned varieties are prone to dry rot, so can they be harvested differently to allow a treatment in store? “That is a potential starting point, rather than the mindset of blanket treating everything or not treating at all.” Growers should learn the strengths and weaknesses of their varieties and make seed treatment decisions based on disease risk. Photo: Blackthorn Arable There has been a rise in tuber disease levels in seed potatoes, with this suspected case of dry rot uncovered during an inspection by the ware grower. Photo: Blackthorn Arable