Table grapes may account for only 15% of the US grape industry, but they generate the highest growing prices, with an average of $718 per tonne, compared with $410/t for wine grapes and $231/t for raisins.

In the UK, Californian table grapes have two windows of ­opportunity, in May and June and again in November and December, to fill the gap between the last European fruit and the start of the southern hemisphere season.

Susan Day, vice president of international marketing at the California Table Grape Commission, says the UK is the world's fourth largest consumer of table grapes, although exports have fluctuated over the past five years. A bumper crop in 2004 saw 14,408 tonnes expor­ted, but last year it dropped to fewer than 9,000 tonnes.

The UK market is a challenging one. "It is sophisticated," says Day. "It pulls from about 25 markets, so there is more competition.

"We want consumers to prefer Californian grapes, but because ­retailers buy from so many different countries consumers aren't aware of where they are from."

She adds that UK buyers look for consistency and high quality, which is something the industry is working on. However, she admits that countries such as ­Brazil, Greece and Spain, which has boosted volume of its ­Crimson Seedless variety, have become more competitive.

To fight the growing competition, the Commission has been working with the USDA on a ­patent and licensing programme for new varieties, which it believes will generate great interest among sophisticated UK buyers. New varieties include Autumn Royal, Scarlet Royal and Sweet Scarlet.

Ross Jones, vice president of ­research at the Commission, says: "We are leading the field in variety development and are keen to educate the UK consumer."

California's biggest variety in the UK is Crimson Seedless, followed by Thompson Seedless, but Jones adds that there is growing interest in black seedless grapes. "Autumn Royal [black seedless] have doubled in production every year. They are really taking off."

The raisin industry, which ­accounts for 28% of the grape indus­try, is also performing well. However, the industry is in constant conflict with wineries that are attracting growers of raisin grapes by paying higher prices. This has not stopped other players entering the category, however.

Prune supplier Sunsweet, for ­example, has launched a raisin brand that it believes can compete with leading brand Sun-Maid. n