Applying CIPC during store loading is becoming an increasingly favoured treatment option to enhance sprout suppression in store. It also ticks a number of stewardship boxes.
Particularly attractive to growers supplying the processing industry, Gro-Stop Ready is a liquid CIPC formulation that is applied immediately after harvest as potatoes go into store, ensuring each tuber is dosed equally and at the same time.
Heralded as a precise application technique, to overcome some of the challenges with traditional fogging treatments, growers are responding to the need for far lower total doses of CIPC throughout the storage period.
Ivan Curran, a crisping producer from Co. Meath, southern Ireland, reports that using Gro-Stop Ready right after harvest to his crop of Sassy means that subsequent fogging treatments are kept to a minimum.
“I treated the crop with Gro-Stop Ready last year as the crop went into store in September, at a rate of 18g per tonne,” he says. “The results have been fantastic.
“The potatoes had three further CIPC fogging treatments, at low application rates of just 6g per tonne, which is one third of the maximum treatment rate. They came out in June this year, with no buds,” notes Ivan. The total CIPC dose received by the crop was well under the 58g per tonne permitted.
“The nature of the liquid and treatment process leads to even distribution. It permits accurate application and there’s hardly any evidence of skin burn. The crop reached the crisping factory with no problems at all,” says Ivan.
Early treatment of crops with Gro-Stop Ready at this UK approved rate of 18g per tonne is in line with new CIPC label changes, approved by CRD, as part of the ongoing CIPC stewardship initiative ‘Be CIPC Compliant’.
Alan Horgan, technical manager for Certis, who supply the Gro-Stop sprout suppressant range, explains that the first application should always be made early, to improve efficacy and help reduce the risk of residues above the Maximum Residue Level (MRL).
He points to this season as a prime example of early harvest promoting early dormancy. “The good thing with Gro-Stop Ready is that it lends itself to early dormancy break because it can be applied at store loading. This is in contrast to fogging, which requires a ‘wound healing’ period, post-harvest.
“With fogging, if good practice is not followed, in terms of both store management and application, some of the crop within a store can potentially receive high doses of CIPC. Repeat applications could then lead to the MRL being exceeded,” says Alan.
The value of early treatment was confirmed in a recent trial carried out at Sutton Bridge, conducted by Certis in partnership with McCain. It revealed that treatment within three hours of harvest with Gro-Stop Ready effectively suppressed sprouting in store for up to five months.
In the trial, Gro-Stop Ready was applied to 12 potato varieties, at store loading, on a conveyer at a rate of 150ml per tonne (18g CIPC per tonne). Storage conditions during the trial reflected a typical commercial environment.
Alan is encouraged by the trial results. “For the processing industry this is good news, because a low level of skin burn can be peeled away. UK chippers are already using it on Maris Piper; it’s also being used on newer varieties in Ireland.”
Alan notes that some growers are understandably reluctant to apply a sprout suppressant immediately after harvest, due to the fact that some varieties are more susceptible to skin burn than others. “However, the trial results showed minimal evidence of skin burn in newer varieties and a maximum level of under one millimetre in highly susceptible crops.”
Growers supplying the processing industry are confirming the trial results and the benefits of early CIPC treatment during store loading.
Alan suggests further considerations for storage success. “Growers should be diligent with varietal choice. Gro-Stop Ready treatment needs to be applied to a dry, clean crop with dirt removed, and damaged potatoes should be discarded to ensure best possible storage results.”