Reglone now recommended for all soil conditions

New recommendations for split-dose Reglone application this season will enable all potato growers to desiccate their crops safely and more cost effectively - no matter what the soil conditions.

Research and field trials have shown that even in the driest conditions, an initial low dose of Reglone sets the desiccation process in progress, but poses no threat to tuber quality, reports Syngenta Technical Manager, Jon Ogborn. In fact, it could reduce the risk of damage if applied prior to flailing crops under drought stress.

In dry soil conditions, where growers may have been wary of using Reglone in the past, he advises an initial application of up to 1.0 l/ha will trigger the crop into senescence, without increasing the risk of tuber damage. "Growers can safely follow the initial application with up to 3.0 l/ha of Reglone - five to seven days later - to complete the desiccation process.

"The initial low dose is sufficient to stop tuber bulking and initiate skin set. However, the gentle shut down of the plant minimises risk of internal vascular browning and allows stolons to detach from tubers cleanly, ensuring optimum tuber quality. Growers can complete the desiccation process with an additional Reglone application."

He advises that growers should undertake the simple in-field SMART test (Soil Moisture Assessment for Reglone Treatment) prior to treatment. Whereas previously growers were advised to avoid use of Reglone if the result was a FAIL, the difference now is that where the result is FAIL or BORDERLINE (the soil around the tubers is too dry be squeezed into a ball that retains its shape), Reglone can still be used, but with the initial application limited to no more than 1.0 l/ha.

"If soils pass the SMART test we would advise that the initial dose may be up to 2 l/ha - depending on crop vigour - followed by a subsequent application up to a total of 4 l/ha Reglone per crop. In trials 1.5 l/ha followed by 2.5 l/ha has proved to be a very effective treatment."

Mr Ogborn believes the low rate Reglone application will also be of huge benefit to growers who flail potato crop haulm, particularly if their crops are under stress in dry conditions. "The shock of instant defoliation with mechanical flailing can result in the highest levels of tuber damage and vascular browning," he reports. "Using Reglone to trigger the plants into senescence five to seven days before you plan to flail can really help to minimise the risk of damage. Tank-mixing the Reglone with a Shirlan blight fungicide application saves time and costs, plus ensures very effective tuber blight protection."

He adds that the initial low dose of Reglone may also help reduce the risk of bruising in drought stressed crops, by limiting the crop's water demand and enabling tubers to re-hydrate prior to the main defoliation.

Mr Ogborn highlights a split dose Reglone programme typically costs around £45/ha - well under half that of acid application and 50% cheaper than flail and spray desiccation. "There is now the real opportunity for all potato growers to make a significant saving in desiccation costs, whilst still achieving equally good, or better, control of tuber size and tuber quality," he adds.