Warning for potato growers

Up until a few years ago, potato growers used a dilute form of sulphuric acid to kill of the haulm of their potato crops and thus help set the skins of the tubers. It was very quick and effective, but it was also very nasty, and not at all good for the flora and fauna in the same field.

Similar environmental problems also existed with diquat which replaced the use of acid until it too was banned several years ago.

Now potato growers have been warned their crops are at risk of virus and disease problems if they do not follow an integrated approach to new desiccation regimes.

Work on AHDB trial sites have shown that the slower “kill” achieved by the chemical and mechanical alternatives now used means that green stems and leaves can still be present up to three weeks after desiccation sprays.

According to Eric Anderson, senior agronomist for Scottish Agronomy, who is leading trial work on the issue at Milton of Mathers farm near Montrose: “Not all growers will be thinking about virus threat when desiccating, but you can find aphids on green regrowth up to three weeks after you spray. “Even very small amounts of ‘green material’ remain a viable target for virus-carrying aphids and diseases, such as blight and gangrene.”

The warning was not confined to seed potato growers, added Anderson: “Even for ware and processing growers, the presence of green leaves and stems means the threat of foliar and tuber blight, which needs to be managed.”