Warm, humid weather leads to first blight warning of the year

Potato blight outbreaks have been reported in Wexford, Waterford and Kerry as Met Éireann yesterday issued its first blight warning of the summer.

The warning means wet, warm and humid conditions are expected over the next few days.

According to meteorologist Gerry Scully, blight weather conditions occur when temperatures remain above 10 degrees with relative humidity of 90 per cent.

"It will be getting very moist and mild over the next few days with temperatures in the high teens," he said. "Any time you get a combination of moist conditions, high temperatures and rainfall you get conditions conducive to the spread of potato blight."

Met Éireann advised yesterday was suitable for spraying against blight, with slack winds and dry conditions.

Tom Maher of Teagasc said that early outbreaks of potato blight had been reported in Kerry, Wexford and Waterford.

Fungicides such as cymoxanil are sprayed as a curative for already infected crops, while systemic fungicides to prevent blight are sprayed early in the season. These are absorbed into the sap of the potato, while contact or protectant fungicide is used for the rest of the season, and is only used on the leaves. Blight warnings are sometimes issued as early as April, but usually from July to the end of August.

Mr Maher said that one-third of the Republic's estimated 650 potato growers are expected to spray the first and second early season crops and early main crops. Early season potatoes are harvested from June to August, while main season potatoes, planted in March and April, are harvested from September onwards.

Asked if there was a way to eliminate potato blight permanently, the Teagasc expert said, "We've had potato blight since it was first recorded in the Botanic Gardens on 20th August, 1845 and we still have it on 1st June 2005."

About 30,000 acres of land are used for potato cultivation and in the past five years the number of growers has decreased from 956 in 2000 to about 650 this year.

According to Kieran Leddy, the IFA's potato and horticulture secretary, between 450,000 and 500,000 tonnes of potatoes are cultivated annually, with 150 of the largest growers producing 75 per cent of the crop.

The Rooster variety accounts for 40 per cent of consumption with Kerr's Pink, British Queens, Records and Golden Wonder making up the remainder.